blob: 46aee1b957de12ac6cb546d95b1ba74c6a5cf2dd [file] [log] [blame]
/*
* Copyright 2020 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/private/SkSLProgramElement.h"
#include "include/private/SkSLStatement.h"
#include "include/private/SkTArray.h"
#include "include/private/SkTPin.h"
#include "src/sksl/SkSLCompiler.h"
#include "src/sksl/SkSLOperators.h"
#include "src/sksl/codegen/SkSLCodeGenerator.h"
#include "src/sksl/codegen/SkSLVMCodeGenerator.h"
#include "src/sksl/ir/SkSLBinaryExpression.h"
#include "src/sksl/ir/SkSLBlock.h"
#include "src/sksl/ir/SkSLBreakStatement.h"
#include "src/sksl/ir/SkSLChildCall.h"
#include "src/sksl/ir/SkSLConstructor.h"
#include "src/sksl/ir/SkSLConstructorArray.h"
#include "src/sksl/ir/SkSLConstructorArrayCast.h"
#include "src/sksl/ir/SkSLConstructorDiagonalMatrix.h"
#include "src/sksl/ir/SkSLConstructorMatrixResize.h"
#include "src/sksl/ir/SkSLConstructorSplat.h"
#include "src/sksl/ir/SkSLConstructorStruct.h"
#include "src/sksl/ir/SkSLContinueStatement.h"
#include "src/sksl/ir/SkSLDoStatement.h"
#include "src/sksl/ir/SkSLExpressionStatement.h"
#include "src/sksl/ir/SkSLExternalFunctionCall.h"
#include "src/sksl/ir/SkSLExternalFunctionReference.h"
#include "src/sksl/ir/SkSLFieldAccess.h"
#include "src/sksl/ir/SkSLForStatement.h"
#include "src/sksl/ir/SkSLFunctionCall.h"
#include "src/sksl/ir/SkSLFunctionDeclaration.h"
#include "src/sksl/ir/SkSLFunctionDefinition.h"
#include "src/sksl/ir/SkSLIfStatement.h"
#include "src/sksl/ir/SkSLIndexExpression.h"
#include "src/sksl/ir/SkSLLiteral.h"
#include "src/sksl/ir/SkSLPostfixExpression.h"
#include "src/sksl/ir/SkSLPrefixExpression.h"
#include "src/sksl/ir/SkSLReturnStatement.h"
#include "src/sksl/ir/SkSLSwitchStatement.h"
#include "src/sksl/ir/SkSLSwizzle.h"
#include "src/sksl/ir/SkSLTernaryExpression.h"
#include "src/sksl/ir/SkSLVarDeclarations.h"
#include "src/sksl/ir/SkSLVariableReference.h"
#include "src/sksl/tracing/SkVMDebugTrace.h"
#include <algorithm>
#include <unordered_map>
namespace {
// sksl allows the optimizations of fast_mul(), so we want to use that most of the time.
// This little sneaky snippet of code lets us use ** as a fast multiply infix operator.
struct FastF32 { skvm::F32 val; };
static FastF32 operator*(skvm::F32 y) { return {y}; }
static skvm::F32 operator*(skvm::F32 x, FastF32 y) { return fast_mul(x, y.val); }
static skvm::F32 operator*(float x, FastF32 y) { return fast_mul(x, y.val); }
class SkSLTracer : public skvm::TraceHook {
public:
static std::unique_ptr<SkSLTracer> Make(SkSL::SkVMDebugTrace* trace) {
auto hook = std::make_unique<SkSLTracer>();
hook->fTrace = trace;
return hook;
}
void line(int lineNum) override {
fTrace->fTraceInfo.push_back({SkSL::SkVMTraceInfo::Op::kLine,
/*data=*/{lineNum, 0}});
}
void var(int slot, int32_t val) override {
fTrace->fTraceInfo.push_back({SkSL::SkVMTraceInfo::Op::kVar,
/*data=*/{slot, val}});
}
void enter(int fnIdx) override {
fTrace->fTraceInfo.push_back({SkSL::SkVMTraceInfo::Op::kEnter,
/*data=*/{fnIdx, 0}});
}
void exit(int fnIdx) override {
fTrace->fTraceInfo.push_back({SkSL::SkVMTraceInfo::Op::kExit,
/*data=*/{fnIdx, 0}});
}
void scope(int delta) override {
fTrace->fTraceInfo.push_back({SkSL::SkVMTraceInfo::Op::kScope,
/*data=*/{delta, 0}});
}
private:
SkSL::SkVMDebugTrace* fTrace;
};
} // namespace
namespace SkSL {
namespace {
// Holds scalars, vectors, or matrices
struct Value {
Value() = default;
explicit Value(size_t slots) {
fVals.resize(slots);
}
Value(skvm::F32 x) : fVals({ x.id }) {}
Value(skvm::I32 x) : fVals({ x.id }) {}
explicit operator bool() const { return !fVals.empty(); }
size_t slots() const { return fVals.size(); }
struct ValRef {
ValRef(skvm::Val& val) : fVal(val) {}
// Required until C++17 copy elision
ValRef(const ValRef&) = default;
ValRef& operator=(ValRef v) { fVal = v.fVal; return *this; }
ValRef& operator=(skvm::Val v) { fVal = v; return *this; }
ValRef& operator=(skvm::F32 v) { fVal = v.id; return *this; }
ValRef& operator=(skvm::I32 v) { fVal = v.id; return *this; }
operator skvm::Val() { return fVal; }
skvm::Val& fVal;
};
ValRef operator[](size_t i) {
// These redundant asserts work around what we think is a codegen bug in GCC 8.x for
// 32-bit x86 Debug builds.
SkASSERT(i < fVals.size());
return fVals[i];
}
skvm::Val operator[](size_t i) const {
// These redundant asserts work around what we think is a codegen bug in GCC 8.x for
// 32-bit x86 Debug builds.
SkASSERT(i < fVals.size());
return fVals[i];
}
SkSpan<skvm::Val> asSpan() { return SkMakeSpan(fVals); }
private:
SkSTArray<4, skvm::Val, true> fVals;
};
} // namespace
class SkVMGenerator {
public:
SkVMGenerator(const Program& program,
skvm::Builder* builder,
SkVMDebugTrace* debugTrace,
SkVMCallbacks* callbacks);
void writeProgram(SkSpan<skvm::Val> uniforms,
skvm::Coord device,
const FunctionDefinition& function,
SkSpan<skvm::Val> arguments,
SkSpan<skvm::Val> outReturn);
private:
/**
* In SkSL, a Variable represents a named, typed value (along with qualifiers, etc).
* Every Variable is mapped to one (or several, contiguous) indices into our vector of
* skvm::Val. Those skvm::Val entries hold the current actual value of that variable.
*
* NOTE: Conceptually, each Variable is just mapped to a Value. We could implement it that way,
* (and eliminate the indirection), but it would add overhead for each Variable,
* and add additional (different) bookkeeping for things like lvalue-swizzles.
*
* Any time a variable appears in an expression, that's a VariableReference, which is a kind of
* Expression. Evaluating that VariableReference (or any other Expression) produces a Value,
* which is a set of skvm::Val. (This allows an Expression to produce a vector or matrix, in
* addition to a scalar).
*
* For a VariableReference, producing a Value is straightforward - we get the slot of the
* Variable (from fVariableMap), use that to look up the current skvm::Vals holding the
* variable's contents, and construct a Value with those ids.
*/
/** Creates a Value from a collection of adjacent slots. */
Value getSlotValue(size_t slot, size_t nslots);
/**
* Returns the slot index of this function inside the SkVMFunctionInfo array in SkVMDebugTrace.
* The SkVMFunctionInfo slot will be created if it doesn't already exist.
*/
int getDebugFunctionInfo(const FunctionDeclaration& decl);
/** Used by `createSlot` to add this variable to the SkVMSlotInfo array inside SkVMDebugTrace.*/
void addDebugSlotInfo(String varName, const Type& type, int line, int fnReturnValue);
/** Used by `getSlot` to create a new slot on its first access. */
size_t createSlot(const String& name, const Type& type, int line, int fnReturnValue);
/**
* Returns the slot holding v's Val(s). Allocates storage if this is first time 'v' is
* referenced. Compound variables (e.g. vectors) will consume more than one slot, with
* getSlot returning the start of the contiguous chunk of slots.
*/
size_t getSlot(const Variable& v);
/**
* Returns the slot holding fn's return value. Allocates storage if this is first time accessing
* the slot.
*/
size_t getSlot(const FunctionDefinition& fn);
/**
* Writes a value to a slot previously created by getSlot.
*/
void writeToSlot(int slot, skvm::Val value);
/**
* Emits an trace_line opcode. writeStatement does this, and statements that alter control flow
* may need to explicitly add additional traces.
*/
void emitTraceLine(int line);
/** Emits an trace_scope opcode, which alters the SkSL variable-scope depth. */
void emitTraceScope(skvm::I32 executionMask, int delta);
/** Initializes uniforms and global variables at the start of main(). */
void setupGlobals(SkSpan<skvm::Val> uniforms, skvm::Coord device);
/** Emits an SkSL function. Returns the slot index of the SkSL function's return value. */
size_t writeFunction(const FunctionDefinition& function, SkSpan<skvm::Val> arguments);
skvm::F32 f32(skvm::Val id) { SkASSERT(id != skvm::NA); return {fBuilder, id}; }
skvm::I32 i32(skvm::Val id) { SkASSERT(id != skvm::NA); return {fBuilder, id}; }
// Shorthand for scalars
skvm::F32 f32(const Value& v) { SkASSERT(v.slots() == 1); return f32(v[0]); }
skvm::I32 i32(const Value& v) { SkASSERT(v.slots() == 1); return i32(v[0]); }
template <typename Fn>
Value unary(const Value& v, Fn&& fn) {
Value result(v.slots());
for (size_t i = 0; i < v.slots(); ++i) {
result[i] = fn({fBuilder, v[i]});
}
return result;
}
skvm::I32 mask() {
// Mask off execution if we have encountered `break` or `continue` on this path.
skvm::I32 result = fConditionMask & fLoopMask;
if (!fFunctionStack.empty()) {
// As we encounter (possibly conditional) return statements, fReturned is updated to
// store the lanes that have already returned. For the remainder of the current
// function, those lanes should be disabled.
result = result & ~currentFunction().fReturned;
}
return result;
}
size_t fieldSlotOffset(const FieldAccess& expr);
size_t indexSlotOffset(const IndexExpression& expr);
Value writeExpression(const Expression& expr);
Value writeBinaryExpression(const BinaryExpression& b);
Value writeAggregationConstructor(const AnyConstructor& c);
Value writeChildCall(const ChildCall& c);
Value writeConstructorDiagonalMatrix(const ConstructorDiagonalMatrix& c);
Value writeConstructorMatrixResize(const ConstructorMatrixResize& c);
Value writeConstructorCast(const AnyConstructor& c);
Value writeConstructorSplat(const ConstructorSplat& c);
Value writeFunctionCall(const FunctionCall& c);
Value writeExternalFunctionCall(const ExternalFunctionCall& c);
Value writeFieldAccess(const FieldAccess& expr);
Value writeLiteral(const Literal& l);
Value writeIndexExpression(const IndexExpression& expr);
Value writeIntrinsicCall(const FunctionCall& c);
Value writePostfixExpression(const PostfixExpression& p);
Value writePrefixExpression(const PrefixExpression& p);
Value writeSwizzle(const Swizzle& swizzle);
Value writeTernaryExpression(const TernaryExpression& t);
Value writeVariableExpression(const VariableReference& expr);
Value writeTypeConversion(const Value& src, Type::NumberKind srcKind, Type::NumberKind dstKind);
void writeStatement(const Statement& s);
void writeBlock(const Block& b);
void writeBreakStatement();
void writeContinueStatement();
void writeForStatement(const ForStatement& f);
void writeIfStatement(const IfStatement& stmt);
void writeReturnStatement(const ReturnStatement& r);
void writeSwitchStatement(const SwitchStatement& s);
void writeVarDeclaration(const VarDeclaration& decl);
Value writeStore(const Expression& lhs, const Value& rhs);
skvm::Val writeConditionalStore(skvm::Val lhs, skvm::Val rhs, skvm::I32 mask);
Value writeMatrixInverse2x2(const Value& m);
Value writeMatrixInverse3x3(const Value& m);
Value writeMatrixInverse4x4(const Value& m);
void recursiveBinaryCompare(const Value& lVal, const Type& lType,
const Value& rVal, const Type& rType,
size_t* slotOffset, Value* result,
const std::function <Value(skvm::F32 x, skvm::F32 y)>& float_comp,
const std::function <Value(skvm::I32 x, skvm::I32 y)>& int_comp);
//
// Global state for the lifetime of the generator:
//
const Program& fProgram;
skvm::Builder* fBuilder;
SkVMDebugTrace* fDebugTrace;
int fTraceHookID = -1;
SkVMCallbacks* fCallbacks;
struct Slot {
skvm::Val val;
bool writtenTo = false;
};
std::vector<Slot> fSlots;
// [Variable, first slot in fSlots]
std::unordered_map<const Variable*, size_t> fVariableMap;
// [Function, first slot in fSlots]
std::unordered_map<const FunctionDefinition*, size_t> fReturnValueMap;
// Debug trace mask (set to true when fTraceCoord matches device coordinates)
skvm::I32 fTraceMask;
// Conditional execution mask (managed by ScopedCondition, and tied to control-flow scopes)
skvm::I32 fConditionMask;
// Similar: loop execution masks. Each loop starts with all lanes active (fLoopMask).
// 'break' disables a lane in fLoopMask until the loop finishes
// 'continue' disables a lane in fLoopMask, and sets fContinueMask to be re-enabled on the next
// iteration
skvm::I32 fLoopMask;
skvm::I32 fContinueMask;
//
// State that's local to the generation of a single function:
//
struct Function {
size_t fReturnSlot;
skvm::I32 fReturned;
};
std::vector<Function> fFunctionStack;
Function& currentFunction() { return fFunctionStack.back(); }
class ScopedCondition {
public:
ScopedCondition(SkVMGenerator* generator, skvm::I32 mask)
: fGenerator(generator), fOldConditionMask(fGenerator->fConditionMask) {
fGenerator->fConditionMask &= mask;
}
~ScopedCondition() { fGenerator->fConditionMask = fOldConditionMask; }
private:
SkVMGenerator* fGenerator;
skvm::I32 fOldConditionMask;
};
};
static Type::NumberKind base_number_kind(const Type& type) {
if (type.typeKind() == Type::TypeKind::kMatrix || type.typeKind() == Type::TypeKind::kVector) {
return base_number_kind(type.componentType());
}
return type.numberKind();
}
static inline bool is_uniform(const SkSL::Variable& var) {
return var.modifiers().fFlags & Modifiers::kUniform_Flag;
}
SkVMGenerator::SkVMGenerator(const Program& program,
skvm::Builder* builder,
SkVMDebugTrace* debugTrace,
SkVMCallbacks* callbacks)
: fProgram(program)
, fBuilder(builder)
, fDebugTrace(debugTrace)
, fCallbacks(callbacks) {}
void SkVMGenerator::writeProgram(SkSpan<skvm::Val> uniforms,
skvm::Coord device,
const FunctionDefinition& function,
SkSpan<skvm::Val> arguments,
SkSpan<skvm::Val> outReturn) {
fConditionMask = fLoopMask = fBuilder->splat(0xffff'ffff);
this->setupGlobals(uniforms, device);
size_t returnSlot = this->writeFunction(function, arguments);
// Copy the value from the return slot into outReturn.
SkASSERT(function.declaration().returnType().slotCount() == outReturn.size());
for (size_t i = 0; i < outReturn.size(); ++i) {
outReturn[i] = fSlots[returnSlot + i].val;
}
}
void SkVMGenerator::setupGlobals(SkSpan<skvm::Val> uniforms, skvm::Coord device) {
if (fDebugTrace) {
// Copy the program source into the debug info so that it will be written in the trace file.
fDebugTrace->setSource(*fProgram.fSource);
// Create a trace hook and attach it to the builder.
fDebugTrace->fTraceHook = SkSLTracer::Make(fDebugTrace);
fTraceHookID = fBuilder->attachTraceHook(fDebugTrace->fTraceHook.get());
// The SkVM blitter generates centered pixel coordinates. (0.5, 1.5, 2.5, 3.5, etc.)
// Add 0.5 to the requested trace coordinate to match this.
skvm::Coord traceCoord = {to_F32(fBuilder->splat(fDebugTrace->fTraceCoord.fX)) + 0.5f,
to_F32(fBuilder->splat(fDebugTrace->fTraceCoord.fY)) + 0.5f};
// If we are debugging, we need to create a trace mask. This will be true when the current
// device coordinates match the requested trace coordinates. We calculate each mask
// individually to guarantee consistent order-of-evaluation.
skvm::I32 xMask = (device.x == traceCoord.x),
yMask = (device.y == traceCoord.y);
fTraceMask = xMask & yMask;
}
// Add storage for each global variable (including uniforms) to fSlots, and entries in
// fVariableMap to remember where every variable is stored.
const skvm::Val* uniformIter = uniforms.begin();
size_t fpCount = 0;
for (const ProgramElement* e : fProgram.elements()) {
if (e->is<GlobalVarDeclaration>()) {
const GlobalVarDeclaration& gvd = e->as<GlobalVarDeclaration>();
const VarDeclaration& decl = gvd.declaration()->as<VarDeclaration>();
const Variable& var = decl.var();
SkASSERT(fVariableMap.find(&var) == fVariableMap.end());
// For most variables, fVariableMap stores an index into fSlots, but for children,
// fVariableMap stores the index to pass to fSample(Shader|ColorFilter|Blender)
if (var.type().isEffectChild()) {
fVariableMap[&var] = fpCount++;
continue;
}
// Opaque types include child processors and GL objects (samplers, textures, etc).
// Of those, only child processors are legal variables.
SkASSERT(!var.type().isVoid());
SkASSERT(!var.type().isOpaque());
// getSlot() allocates space for the variable's value in fSlots, initializes it to zero,
// and populates fVariableMap.
size_t slot = this->getSlot(var),
nslots = var.type().slotCount();
// builtin variables are system-defined, with special semantics. The only builtin
// variable exposed to runtime effects is sk_FragCoord.
if (int builtin = var.modifiers().fLayout.fBuiltin; builtin >= 0) {
switch (builtin) {
case SK_FRAGCOORD_BUILTIN:
SkASSERT(nslots == 4);
this->writeToSlot(slot + 0, device.x.id);
this->writeToSlot(slot + 1, device.y.id);
this->writeToSlot(slot + 2, fBuilder->splat(0.0f).id);
this->writeToSlot(slot + 3, fBuilder->splat(1.0f).id);
break;
default:
SkDEBUGFAILF("Unsupported builtin %d", builtin);
}
continue;
}
// For uniforms, copy the supplied IDs over
if (is_uniform(var)) {
SkASSERT(uniformIter + nslots <= uniforms.end());
for (size_t i = 0; i < nslots; ++i) {
this->writeToSlot(slot + i, uniformIter[i]);
}
uniformIter += nslots;
continue;
}
// For other globals, populate with the initializer expression (if there is one)
if (decl.value()) {
Value val = this->writeExpression(*decl.value());
for (size_t i = 0; i < nslots; ++i) {
this->writeToSlot(slot + i, val[i]);
}
}
}
}
SkASSERT(uniformIter == uniforms.end());
}
Value SkVMGenerator::getSlotValue(size_t slot, size_t nslots) {
Value val(nslots);
for (size_t i = 0; i < nslots; ++i) {
val[i] = fSlots[slot + i].val;
}
return val;
}
int SkVMGenerator::getDebugFunctionInfo(const FunctionDeclaration& decl) {
SkASSERT(fDebugTrace);
std::string name = decl.description();
// Look for a matching SkVMFunctionInfo slot.
for (size_t index = 0; index < fDebugTrace->fFuncInfo.size(); ++index) {
if (fDebugTrace->fFuncInfo[index].name == name) {
return index;
}
}
// We've never called this function before; create a new slot to hold its information.
int slot = (int)fDebugTrace->fFuncInfo.size();
fDebugTrace->fFuncInfo.push_back(SkVMFunctionInfo{std::move(name)});
return slot;
}
size_t SkVMGenerator::writeFunction(const FunctionDefinition& function,
SkSpan<skvm::Val> arguments) {
const FunctionDeclaration& decl = function.declaration();
int funcIndex = -1;
if (fDebugTrace) {
funcIndex = this->getDebugFunctionInfo(decl);
fBuilder->trace_enter(fTraceHookID, this->mask(), fTraceMask, funcIndex);
}
size_t returnSlot = this->getSlot(function);
fFunctionStack.push_back({/*fReturnSlot=*/returnSlot, /*fReturned=*/fBuilder->splat(0)});
// For all parameters, copy incoming argument IDs to our vector of (all) variable IDs
size_t argIdx = 0;
for (const Variable* p : decl.parameters()) {
size_t paramSlot = this->getSlot(*p),
nslots = p->type().slotCount();
for (size_t i = 0; i < nslots; ++i) {
fSlots[paramSlot + i].writtenTo = false;
this->writeToSlot(paramSlot + i, arguments[argIdx + i]);
}
argIdx += nslots;
}
SkASSERT(argIdx == arguments.size());
this->writeStatement(*function.body());
// Copy 'out' and 'inout' parameters back to their caller-supplied argument storage
argIdx = 0;
for (const Variable* p : decl.parameters()) {
size_t nslots = p->type().slotCount();
if (p->modifiers().fFlags & Modifiers::kOut_Flag) {
size_t paramSlot = this->getSlot(*p);
for (size_t i = 0; i < nslots; ++i) {
arguments[argIdx + i] = fSlots[paramSlot + i].val;
}
}
argIdx += nslots;
}
SkASSERT(argIdx == arguments.size());
fFunctionStack.pop_back();
if (fDebugTrace) {
fBuilder->trace_exit(fTraceHookID, this->mask(), fTraceMask, funcIndex);
}
return returnSlot;
}
void SkVMGenerator::writeToSlot(int slot, skvm::Val value) {
if (fDebugTrace && (!fSlots[slot].writtenTo || fSlots[slot].val != value)) {
if (fProgram.fConfig->fSettings.fAllowTraceVarInSkVMDebugTrace) {
fBuilder->trace_var(fTraceHookID, this->mask(), fTraceMask, slot, i32(value));
}
fSlots[slot].writtenTo = true;
}
fSlots[slot].val = value;
}
void SkVMGenerator::addDebugSlotInfo(String varName,
const Type& type,
int line,
int fnReturnValue) {
SkASSERT(fDebugTrace);
switch (type.typeKind()) {
case Type::TypeKind::kArray: {
int nslots = type.columns();
const Type& elemType = type.componentType();
for (int slot = 0; slot < nslots; ++slot) {
this->addDebugSlotInfo(varName + "[" + to_string(slot) + "]",
elemType, line, fnReturnValue);
}
break;
}
case Type::TypeKind::kStruct: {
for (const Type::Field& field : type.fields()) {
this->addDebugSlotInfo(varName + "." + field.fName,
*field.fType, line, fnReturnValue);
}
break;
}
default:
SkASSERTF(0, "unsupported slot type %d", (int)type.typeKind());
[[fallthrough]];
case Type::TypeKind::kScalar:
case Type::TypeKind::kVector:
case Type::TypeKind::kMatrix: {
Type::NumberKind numberKind = type.componentType().numberKind();
int nslots = type.slotCount();
for (int slot = 0; slot < nslots; ++slot) {
SkVMSlotInfo slotInfo;
slotInfo.name = varName;
slotInfo.columns = type.columns();
slotInfo.rows = type.rows();
slotInfo.componentIndex = slot;
slotInfo.numberKind = numberKind;
slotInfo.line = line;
slotInfo.fnReturnValue = fnReturnValue;
fDebugTrace->fSlotInfo.push_back(std::move(slotInfo));
}
break;
}
}
}
size_t SkVMGenerator::createSlot(const String& name,
const Type& type,
int line,
int fnReturnValue) {
size_t slot = fSlots.size(),
nslots = type.slotCount();
if (nslots > 0) {
if (fDebugTrace) {
// Our debug slot-info table should have the same length as the actual slot table.
SkASSERT(fDebugTrace->fSlotInfo.size() == slot);
// Append slot names and types to our debug slot-info table.
fDebugTrace->fSlotInfo.reserve(slot + nslots);
this->addDebugSlotInfo(name, type, line, fnReturnValue);
// Confirm that we added the expected number of slots.
SkASSERT(fDebugTrace->fSlotInfo.size() == (slot + nslots));
}
// Create brand new slots initialized to zero.
skvm::Val initialValue = fBuilder->splat(0.0f).id;
fSlots.insert(fSlots.end(), nslots, Slot{initialValue});
}
return slot;
}
size_t SkVMGenerator::getSlot(const Variable& v) {
auto entry = fVariableMap.find(&v);
if (entry != fVariableMap.end()) {
return entry->second;
}
size_t slot = this->createSlot(String(v.name()), v.type(), v.fLine, /*fnReturnValue=*/-1);
fVariableMap[&v] = slot;
return slot;
}
size_t SkVMGenerator::getSlot(const FunctionDefinition& fn) {
auto entry = fReturnValueMap.find(&fn);
if (entry != fReturnValueMap.end()) {
return entry->second;
}
const FunctionDeclaration& decl = fn.declaration();
int fnReturnValue = fDebugTrace ? this->getDebugFunctionInfo(decl) : -1;
size_t slot = this->createSlot("[" + decl.name() + "].result",
decl.returnType(),
fn.fLine,
fnReturnValue);
fReturnValueMap[&fn] = slot;
return slot;
}
void SkVMGenerator::recursiveBinaryCompare(
const Value& lVal,
const Type& lType,
const Value& rVal,
const Type& rType,
size_t* slotOffset,
Value* result,
const std::function<Value(skvm::F32 x, skvm::F32 y)>& float_comp,
const std::function<Value(skvm::I32 x, skvm::I32 y)>& int_comp) {
switch (lType.typeKind()) {
case Type::TypeKind::kStruct:
SkASSERT(rType.typeKind() == Type::TypeKind::kStruct);
// Go through all the fields
for (size_t f = 0; f < lType.fields().size(); ++f) {
const Type::Field& lField = lType.fields()[f];
const Type::Field& rField = rType.fields()[f];
this->recursiveBinaryCompare(lVal,
*lField.fType,
rVal,
*rField.fType,
slotOffset,
result,
float_comp,
int_comp);
}
break;
case Type::TypeKind::kArray:
case Type::TypeKind::kVector:
case Type::TypeKind::kMatrix:
SkASSERT(lType.typeKind() == rType.typeKind());
// Go through all the elements
for (int c = 0; c < lType.columns(); ++c) {
this->recursiveBinaryCompare(lVal,
lType.componentType(),
rVal,
rType.componentType(),
slotOffset,
result,
float_comp,
int_comp);
}
break;
default:
SkASSERT(lType.typeKind() == rType.typeKind() &&
lType.slotCount() == rType.slotCount());
Type::NumberKind nk = base_number_kind(lType);
auto L = lVal[*slotOffset];
auto R = rVal[*slotOffset];
(*result)[*slotOffset] =
i32(nk == Type::NumberKind::kFloat
? float_comp(f32(L), f32(R))
: int_comp(i32(L), i32(R))).id;
*slotOffset += lType.slotCount();
break;
}
}
Value SkVMGenerator::writeBinaryExpression(const BinaryExpression& b) {
const Expression& left = *b.left();
const Expression& right = *b.right();
Operator op = b.getOperator();
if (op.kind() == Token::Kind::TK_EQ) {
return this->writeStore(left, this->writeExpression(right));
}
const Type& lType = left.type();
const Type& rType = right.type();
bool lVecOrMtx = (lType.isVector() || lType.isMatrix());
bool rVecOrMtx = (rType.isVector() || rType.isMatrix());
bool isAssignment = op.isAssignment();
if (isAssignment) {
op = op.removeAssignment();
}
Type::NumberKind nk = base_number_kind(lType);
// A few ops require special treatment:
switch (op.kind()) {
case Token::Kind::TK_LOGICALAND: {
SkASSERT(!isAssignment);
SkASSERT(nk == Type::NumberKind::kBoolean);
skvm::I32 lVal = i32(this->writeExpression(left));
ScopedCondition shortCircuit(this, lVal);
skvm::I32 rVal = i32(this->writeExpression(right));
return lVal & rVal;
}
case Token::Kind::TK_LOGICALOR: {
SkASSERT(!isAssignment);
SkASSERT(nk == Type::NumberKind::kBoolean);
skvm::I32 lVal = i32(this->writeExpression(left));
ScopedCondition shortCircuit(this, ~lVal);
skvm::I32 rVal = i32(this->writeExpression(right));
return lVal | rVal;
}
case Token::Kind::TK_COMMA:
// We write the left side of the expression to preserve its side effects, even though we
// immediately discard the result.
this->writeExpression(left);
return this->writeExpression(right);
default:
break;
}
// All of the other ops always evaluate both sides of the expression
Value lVal = this->writeExpression(left),
rVal = this->writeExpression(right);
// Special case for M*V, V*M, M*M (but not V*V!)
if (op.kind() == Token::Kind::TK_STAR
&& lVecOrMtx && rVecOrMtx && !(lType.isVector() && rType.isVector())) {
int rCols = rType.columns(),
rRows = rType.rows(),
lCols = lType.columns(),
lRows = lType.rows();
// M*V treats the vector as a column
if (rType.isVector()) {
std::swap(rCols, rRows);
}
SkASSERT(lCols == rRows);
SkASSERT(b.type().slotCount() == static_cast<size_t>(lRows * rCols));
Value result(lRows * rCols);
size_t resultIdx = 0;
const skvm::F32 zero = fBuilder->splat(0.0f);
for (int c = 0; c < rCols; ++c)
for (int r = 0; r < lRows; ++r) {
skvm::F32 sum = zero;
for (int j = 0; j < lCols; ++j) {
sum += f32(lVal[j*lRows + r]) * f32(rVal[c*rRows + j]);
}
result[resultIdx++] = sum;
}
SkASSERT(resultIdx == result.slots());
return isAssignment ? this->writeStore(left, result) : result;
}
size_t nslots = std::max(lVal.slots(), rVal.slots());
auto binary = [&](const std::function <Value(skvm::F32 x, skvm::F32 y)>& f_fn,
const std::function <Value(skvm::I32 x, skvm::I32 y)>& i_fn,
bool foldResults = false) -> Value {
Value result(nslots);
if (op.isEquality() && (lType.typeKind() == Type::TypeKind::kStruct ||
lType.typeKind() == Type::TypeKind::kArray)) {
// Shifting over lVal and rVal
size_t slotOffset = 0;
this->recursiveBinaryCompare(
lVal, lType, rVal, rType, &slotOffset, &result, f_fn, i_fn);
SkASSERT(slotOffset == nslots);
} else {
for (size_t slot = 0; slot < nslots; ++slot) {
// If one side is scalar, replicate it to all channels
skvm::Val L = lVal.slots() == 1 ? lVal[0] : lVal[slot],
R = rVal.slots() == 1 ? rVal[0] : rVal[slot];
if (nk == Type::NumberKind::kFloat) {
result[slot] = i32(f_fn(f32(L), f32(R)));
} else {
result[slot] = i32(i_fn(i32(L), i32(R)));
}
}
}
if (foldResults) {
// Just to be more explicit here we ask for a parameter and not detect it ourselves
SkASSERT(op.isEquality());
skvm::I32 folded = i32(result[0]);
for (size_t i = 1; i < nslots; ++i) {
if (op.kind() == Token::Kind::TK_NEQ) {
folded |= i32(result[i]);
} else {
folded &= i32(result[i]);
}
}
return folded;
}
return isAssignment ? this->writeStore(left, result) : result;
};
auto unsupported_f = [&](skvm::F32, skvm::F32) {
SkDEBUGFAIL("Unsupported operator");
return skvm::F32{};
};
switch (op.kind()) {
case Token::Kind::TK_EQEQ:
SkASSERT(!isAssignment);
return binary([](skvm::F32 x, skvm::F32 y) { return x == y; },
[](skvm::I32 x, skvm::I32 y) { return x == y; }, /*foldResults=*/ true);
case Token::Kind::TK_NEQ:
SkASSERT(!isAssignment);
return binary([](skvm::F32 x, skvm::F32 y) { return x != y; },
[](skvm::I32 x, skvm::I32 y) { return x != y; }, /*foldResults=*/ true);
case Token::Kind::TK_GT:
return binary([](skvm::F32 x, skvm::F32 y) { return x > y; },
[](skvm::I32 x, skvm::I32 y) { return x > y; });
case Token::Kind::TK_GTEQ:
return binary([](skvm::F32 x, skvm::F32 y) { return x >= y; },
[](skvm::I32 x, skvm::I32 y) { return x >= y; });
case Token::Kind::TK_LT:
return binary([](skvm::F32 x, skvm::F32 y) { return x < y; },
[](skvm::I32 x, skvm::I32 y) { return x < y; });
case Token::Kind::TK_LTEQ:
return binary([](skvm::F32 x, skvm::F32 y) { return x <= y; },
[](skvm::I32 x, skvm::I32 y) { return x <= y; });
case Token::Kind::TK_PLUS:
return binary([](skvm::F32 x, skvm::F32 y) { return x + y; },
[](skvm::I32 x, skvm::I32 y) { return x + y; });
case Token::Kind::TK_MINUS:
return binary([](skvm::F32 x, skvm::F32 y) { return x - y; },
[](skvm::I32 x, skvm::I32 y) { return x - y; });
case Token::Kind::TK_STAR:
return binary([](skvm::F32 x, skvm::F32 y) { return x ** y; },
[](skvm::I32 x, skvm::I32 y) { return x * y; });
case Token::Kind::TK_SLASH:
// Minimum spec (GLSL ES 1.0) has very loose requirements for integer operations.
// (Low-end GPUs may not have integer ALUs). Given that, we are allowed to do floating
// point division plus rounding. Section 10.28 of the spec even clarifies that the
// rounding mode is undefined (but round-towards-zero is the obvious/common choice).
return binary([](skvm::F32 x, skvm::F32 y) { return x / y; },
[](skvm::I32 x, skvm::I32 y) {
return skvm::trunc(skvm::to_F32(x) / skvm::to_F32(y));
});
case Token::Kind::TK_BITWISEXOR:
case Token::Kind::TK_LOGICALXOR:
return binary(unsupported_f, [](skvm::I32 x, skvm::I32 y) { return x ^ y; });
case Token::Kind::TK_BITWISEAND:
return binary(unsupported_f, [](skvm::I32 x, skvm::I32 y) { return x & y; });
case Token::Kind::TK_BITWISEOR:
return binary(unsupported_f, [](skvm::I32 x, skvm::I32 y) { return x | y; });
// These three operators are all 'reserved' (illegal) in our minimum spec, but will require
// implementation in the future.
case Token::Kind::TK_PERCENT:
case Token::Kind::TK_SHL:
case Token::Kind::TK_SHR:
default:
SkDEBUGFAIL("Unsupported operator");
return {};
}
}
Value SkVMGenerator::writeAggregationConstructor(const AnyConstructor& c) {
Value result(c.type().slotCount());
size_t resultIdx = 0;
for (const auto &arg : c.argumentSpan()) {
Value tmp = this->writeExpression(*arg);
for (size_t tmpSlot = 0; tmpSlot < tmp.slots(); ++tmpSlot) {
result[resultIdx++] = tmp[tmpSlot];
}
}
return result;
}
Value SkVMGenerator::writeTypeConversion(const Value& src,
Type::NumberKind srcKind,
Type::NumberKind dstKind) {
// Conversion among "similar" types (floatN <-> halfN), (shortN <-> intN), etc. is a no-op.
if (srcKind == dstKind) {
return src;
}
// TODO: Handle signed vs. unsigned. GLSL ES 1.0 only has 'int', so no problem yet.
Value dst(src.slots());
switch (dstKind) {
case Type::NumberKind::kFloat:
if (srcKind == Type::NumberKind::kSigned) {
// int -> float
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = skvm::to_F32(i32(src[i]));
}
return dst;
}
if (srcKind == Type::NumberKind::kBoolean) {
// bool -> float
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = skvm::select(i32(src[i]), 1.0f, 0.0f);
}
return dst;
}
break;
case Type::NumberKind::kSigned:
if (srcKind == Type::NumberKind::kFloat) {
// float -> int
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = skvm::trunc(f32(src[i]));
}
return dst;
}
if (srcKind == Type::NumberKind::kBoolean) {
// bool -> int
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = skvm::select(i32(src[i]), 1, 0);
}
return dst;
}
break;
case Type::NumberKind::kBoolean:
if (srcKind == Type::NumberKind::kSigned) {
// int -> bool
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = i32(src[i]) != 0;
}
return dst;
}
if (srcKind == Type::NumberKind::kFloat) {
// float -> bool
for (size_t i = 0; i < src.slots(); ++i) {
dst[i] = f32(src[i]) != 0.0;
}
return dst;
}
break;
default:
break;
}
SkDEBUGFAILF("Unsupported type conversion: %d -> %d", (int)srcKind, (int)dstKind);
return {};
}
Value SkVMGenerator::writeConstructorCast(const AnyConstructor& c) {
auto arguments = c.argumentSpan();
SkASSERT(arguments.size() == 1);
const Expression& argument = *arguments.front();
const Type& srcType = argument.type();
const Type& dstType = c.type();
Type::NumberKind srcKind = base_number_kind(srcType);
Type::NumberKind dstKind = base_number_kind(dstType);
Value src = this->writeExpression(argument);
return this->writeTypeConversion(src, srcKind, dstKind);
}
Value SkVMGenerator::writeConstructorSplat(const ConstructorSplat& c) {
SkASSERT(c.type().isVector());
SkASSERT(c.argument()->type().isScalar());
int columns = c.type().columns();
// Splat the argument across all components of a vector.
Value src = this->writeExpression(*c.argument());
Value dst(columns);
for (int i = 0; i < columns; ++i) {
dst[i] = src[0];
}
return dst;
}
Value SkVMGenerator::writeConstructorDiagonalMatrix(const ConstructorDiagonalMatrix& ctor) {
const Type& dstType = ctor.type();
SkASSERT(dstType.isMatrix());
SkASSERT(ctor.argument()->type().matches(dstType.componentType()));
Value src = this->writeExpression(*ctor.argument());
Value dst(dstType.rows() * dstType.columns());
size_t dstIndex = 0;
// Matrix-from-scalar builds a diagonal scale matrix
const skvm::F32 zero = fBuilder->splat(0.0f);
for (int c = 0; c < dstType.columns(); ++c) {
for (int r = 0; r < dstType.rows(); ++r) {
dst[dstIndex++] = (c == r ? f32(src) : zero);
}
}
SkASSERT(dstIndex == dst.slots());
return dst;
}
Value SkVMGenerator::writeConstructorMatrixResize(const ConstructorMatrixResize& ctor) {
const Type& srcType = ctor.argument()->type();
const Type& dstType = ctor.type();
Value src = this->writeExpression(*ctor.argument());
Value dst(dstType.rows() * dstType.columns());
// Matrix-from-matrix uses src where it overlaps, and fills in missing fields with identity.
size_t dstIndex = 0;
for (int c = 0; c < dstType.columns(); ++c) {
for (int r = 0; r < dstType.rows(); ++r) {
if (c < srcType.columns() && r < srcType.rows()) {
dst[dstIndex++] = src[c * srcType.rows() + r];
} else {
dst[dstIndex++] = fBuilder->splat(c == r ? 1.0f : 0.0f);
}
}
}
SkASSERT(dstIndex == dst.slots());
return dst;
}
size_t SkVMGenerator::fieldSlotOffset(const FieldAccess& expr) {
size_t offset = 0;
for (int i = 0; i < expr.fieldIndex(); ++i) {
offset += (*expr.base()->type().fields()[i].fType).slotCount();
}
return offset;
}
Value SkVMGenerator::writeFieldAccess(const FieldAccess& expr) {
Value base = this->writeExpression(*expr.base());
Value field(expr.type().slotCount());
size_t offset = this->fieldSlotOffset(expr);
for (size_t i = 0; i < field.slots(); ++i) {
field[i] = base[offset + i];
}
return field;
}
size_t SkVMGenerator::indexSlotOffset(const IndexExpression& expr) {
Value index = this->writeExpression(*expr.index());
int indexValue = -1;
SkAssertResult(fBuilder->allImm(index[0], &indexValue));
// When indexing by a literal, the front-end guarantees that we don't go out of bounds.
// But when indexing by a loop variable, it's possible to generate out-of-bounds access.
// The GLSL spec leaves that behavior undefined - we'll just clamp everything here.
indexValue = SkTPin(indexValue, 0, expr.base()->type().columns() - 1);
size_t stride = expr.type().slotCount();
return indexValue * stride;
}
Value SkVMGenerator::writeIndexExpression(const IndexExpression& expr) {
Value base = this->writeExpression(*expr.base());
Value element(expr.type().slotCount());
size_t offset = this->indexSlotOffset(expr);
for (size_t i = 0; i < element.slots(); ++i) {
element[i] = base[offset + i];
}
return element;
}
Value SkVMGenerator::writeVariableExpression(const VariableReference& expr) {
size_t slot = this->getSlot(*expr.variable());
return this->getSlotValue(slot, expr.type().slotCount());
}
Value SkVMGenerator::writeMatrixInverse2x2(const Value& m) {
SkASSERT(m.slots() == 4);
skvm::F32 a = f32(m[0]),
b = f32(m[1]),
c = f32(m[2]),
d = f32(m[3]);
skvm::F32 idet = 1.0f / (a*d - b*c);
Value result(m.slots());
result[0] = ( d ** idet);
result[1] = (-b ** idet);
result[2] = (-c ** idet);
result[3] = ( a ** idet);
return result;
}
Value SkVMGenerator::writeMatrixInverse3x3(const Value& m) {
SkASSERT(m.slots() == 9);
skvm::F32 a11 = f32(m[0]), a12 = f32(m[3]), a13 = f32(m[6]),
a21 = f32(m[1]), a22 = f32(m[4]), a23 = f32(m[7]),
a31 = f32(m[2]), a32 = f32(m[5]), a33 = f32(m[8]);
skvm::F32 idet = 1.0f / (a11*a22*a33 + a12*a23*a31 + a13*a21*a32 -
a11*a23*a32 - a12*a21*a33 - a13*a22*a31);
Value result(m.slots());
result[0] = ((a22**a33 - a23**a32) ** idet);
result[1] = ((a23**a31 - a21**a33) ** idet);
result[2] = ((a21**a32 - a22**a31) ** idet);
result[3] = ((a13**a32 - a12**a33) ** idet);
result[4] = ((a11**a33 - a13**a31) ** idet);
result[5] = ((a12**a31 - a11**a32) ** idet);
result[6] = ((a12**a23 - a13**a22) ** idet);
result[7] = ((a13**a21 - a11**a23) ** idet);
result[8] = ((a11**a22 - a12**a21) ** idet);
return result;
}
Value SkVMGenerator::writeMatrixInverse4x4(const Value& m) {
SkASSERT(m.slots() == 16);
skvm::F32 a00 = f32(m[0]), a10 = f32(m[4]), a20 = f32(m[ 8]), a30 = f32(m[12]),
a01 = f32(m[1]), a11 = f32(m[5]), a21 = f32(m[ 9]), a31 = f32(m[13]),
a02 = f32(m[2]), a12 = f32(m[6]), a22 = f32(m[10]), a32 = f32(m[14]),
a03 = f32(m[3]), a13 = f32(m[7]), a23 = f32(m[11]), a33 = f32(m[15]);
skvm::F32 b00 = a00**a11 - a01**a10,
b01 = a00**a12 - a02**a10,
b02 = a00**a13 - a03**a10,
b03 = a01**a12 - a02**a11,
b04 = a01**a13 - a03**a11,
b05 = a02**a13 - a03**a12,
b06 = a20**a31 - a21**a30,
b07 = a20**a32 - a22**a30,
b08 = a20**a33 - a23**a30,
b09 = a21**a32 - a22**a31,
b10 = a21**a33 - a23**a31,
b11 = a22**a33 - a23**a32;
skvm::F32 idet = 1.0f / (b00**b11 - b01**b10 + b02**b09 + b03**b08 - b04**b07 + b05**b06);
b00 *= idet;
b01 *= idet;
b02 *= idet;
b03 *= idet;
b04 *= idet;
b05 *= idet;
b06 *= idet;
b07 *= idet;
b08 *= idet;
b09 *= idet;
b10 *= idet;
b11 *= idet;
Value result(m.slots());
result[ 0] = (a11*b11 - a12*b10 + a13*b09);
result[ 1] = (a02*b10 - a01*b11 - a03*b09);
result[ 2] = (a31*b05 - a32*b04 + a33*b03);
result[ 3] = (a22*b04 - a21*b05 - a23*b03);
result[ 4] = (a12*b08 - a10*b11 - a13*b07);
result[ 5] = (a00*b11 - a02*b08 + a03*b07);
result[ 6] = (a32*b02 - a30*b05 - a33*b01);
result[ 7] = (a20*b05 - a22*b02 + a23*b01);
result[ 8] = (a10*b10 - a11*b08 + a13*b06);
result[ 9] = (a01*b08 - a00*b10 - a03*b06);
result[10] = (a30*b04 - a31*b02 + a33*b00);
result[11] = (a21*b02 - a20*b04 - a23*b00);
result[12] = (a11*b07 - a10*b09 - a12*b06);
result[13] = (a00*b09 - a01*b07 + a02*b06);
result[14] = (a31*b01 - a30*b03 - a32*b00);
result[15] = (a20*b03 - a21*b01 + a22*b00);
return result;
}
Value SkVMGenerator::writeChildCall(const ChildCall& c) {
auto child_it = fVariableMap.find(&c.child());
SkASSERT(child_it != fVariableMap.end());
const Expression* arg = c.arguments()[0].get();
Value argVal = this->writeExpression(*arg);
skvm::Color color;
switch (c.child().type().typeKind()) {
case Type::TypeKind::kShader: {
SkASSERT(c.arguments().size() == 1);
SkASSERT(arg->type().matches(*fProgram.fContext->fTypes.fFloat2));
skvm::Coord coord = {f32(argVal[0]), f32(argVal[1])};
color = fCallbacks->sampleShader(child_it->second, coord);
break;
}
case Type::TypeKind::kColorFilter: {
SkASSERT(c.arguments().size() == 1);
SkASSERT(arg->type().matches(*fProgram.fContext->fTypes.fHalf4) ||
arg->type().matches(*fProgram.fContext->fTypes.fFloat4));
skvm::Color inColor = {f32(argVal[0]), f32(argVal[1]), f32(argVal[2]), f32(argVal[3])};
color = fCallbacks->sampleColorFilter(child_it->second, inColor);
break;
}
case Type::TypeKind::kBlender: {
SkASSERT(c.arguments().size() == 2);
SkASSERT(arg->type().matches(*fProgram.fContext->fTypes.fHalf4) ||
arg->type().matches(*fProgram.fContext->fTypes.fFloat4));
skvm::Color srcColor = {f32(argVal[0]), f32(argVal[1]), f32(argVal[2]), f32(argVal[3])};
arg = c.arguments()[1].get();
argVal = this->writeExpression(*arg);
SkASSERT(arg->type().matches(*fProgram.fContext->fTypes.fHalf4) ||
arg->type().matches(*fProgram.fContext->fTypes.fFloat4));
skvm::Color dstColor = {f32(argVal[0]), f32(argVal[1]), f32(argVal[2]), f32(argVal[3])};
color = fCallbacks->sampleBlender(child_it->second, srcColor, dstColor);
break;
}
default: {
SkDEBUGFAILF("cannot sample from type '%s'", c.child().type().description().c_str());
}
}
Value result(4);
result[0] = color.r;
result[1] = color.g;
result[2] = color.b;
result[3] = color.a;
return result;
}
Value SkVMGenerator::writeIntrinsicCall(const FunctionCall& c) {
IntrinsicKind intrinsicKind = c.function().intrinsicKind();
SkASSERT(intrinsicKind != kNotIntrinsic);
const size_t nargs = c.arguments().size();
const size_t kMaxArgs = 3; // eg: clamp, mix, smoothstep
Value args[kMaxArgs];
SkASSERT(nargs >= 1 && nargs <= SK_ARRAY_COUNT(args));
// All other intrinsics have at most three args, and those can all be evaluated up front:
for (size_t i = 0; i < nargs; ++i) {
args[i] = this->writeExpression(*c.arguments()[i]);
}
Type::NumberKind nk = base_number_kind(c.arguments()[0]->type());
auto binary = [&](auto&& fn) {
// Binary intrinsics are (vecN, vecN), (vecN, float), or (float, vecN)
size_t nslots = std::max(args[0].slots(), args[1].slots());
Value result(nslots);
SkASSERT(args[0].slots() == nslots || args[0].slots() == 1);
SkASSERT(args[1].slots() == nslots || args[1].slots() == 1);
for (size_t i = 0; i < nslots; ++i) {
result[i] = fn({fBuilder, args[0][args[0].slots() == 1 ? 0 : i]},
{fBuilder, args[1][args[1].slots() == 1 ? 0 : i]});
}
return result;
};
auto ternary = [&](auto&& fn) {
// Ternary intrinsics are some combination of vecN and float
size_t nslots = std::max({args[0].slots(), args[1].slots(), args[2].slots()});
Value result(nslots);
SkASSERT(args[0].slots() == nslots || args[0].slots() == 1);
SkASSERT(args[1].slots() == nslots || args[1].slots() == 1);
SkASSERT(args[2].slots() == nslots || args[2].slots() == 1);
for (size_t i = 0; i < nslots; ++i) {
result[i] = fn({fBuilder, args[0][args[0].slots() == 1 ? 0 : i]},
{fBuilder, args[1][args[1].slots() == 1 ? 0 : i]},
{fBuilder, args[2][args[2].slots() == 1 ? 0 : i]});
}
return result;
};
auto dot = [&](const Value& x, const Value& y) {
SkASSERT(x.slots() == y.slots());
skvm::F32 result = f32(x[0]) * f32(y[0]);
for (size_t i = 1; i < x.slots(); ++i) {
result += f32(x[i]) * f32(y[i]);
}
return result;
};
switch (intrinsicKind) {
case k_radians_IntrinsicKind:
return unary(args[0], [](skvm::F32 deg) { return deg * (SK_FloatPI / 180); });
case k_degrees_IntrinsicKind:
return unary(args[0], [](skvm::F32 rad) { return rad * (180 / SK_FloatPI); });
case k_sin_IntrinsicKind: return unary(args[0], skvm::approx_sin);
case k_cos_IntrinsicKind: return unary(args[0], skvm::approx_cos);
case k_tan_IntrinsicKind: return unary(args[0], skvm::approx_tan);
case k_asin_IntrinsicKind: return unary(args[0], skvm::approx_asin);
case k_acos_IntrinsicKind: return unary(args[0], skvm::approx_acos);
case k_atan_IntrinsicKind: return nargs == 1 ? unary(args[0], skvm::approx_atan)
: binary(skvm::approx_atan2);
case k_pow_IntrinsicKind:
return binary([](skvm::F32 x, skvm::F32 y) { return skvm::approx_powf(x, y); });
case k_exp_IntrinsicKind: return unary(args[0], skvm::approx_exp);
case k_log_IntrinsicKind: return unary(args[0], skvm::approx_log);
case k_exp2_IntrinsicKind: return unary(args[0], skvm::approx_pow2);
case k_log2_IntrinsicKind: return unary(args[0], skvm::approx_log2);
case k_sqrt_IntrinsicKind: return unary(args[0], skvm::sqrt);
case k_inversesqrt_IntrinsicKind:
return unary(args[0], [](skvm::F32 x) { return 1.0f / skvm::sqrt(x); });
case k_abs_IntrinsicKind: return unary(args[0], skvm::abs);
case k_sign_IntrinsicKind:
return unary(args[0], [](skvm::F32 x) { return select(x < 0, -1.0f,
select(x > 0, +1.0f, 0.0f)); });
case k_floor_IntrinsicKind: return unary(args[0], skvm::floor);
case k_ceil_IntrinsicKind: return unary(args[0], skvm::ceil);
case k_fract_IntrinsicKind: return unary(args[0], skvm::fract);
case k_mod_IntrinsicKind:
return binary([](skvm::F32 x, skvm::F32 y) { return x - y*skvm::floor(x / y); });
case k_min_IntrinsicKind:
return binary([](skvm::F32 x, skvm::F32 y) { return skvm::min(x, y); });
case k_max_IntrinsicKind:
return binary([](skvm::F32 x, skvm::F32 y) { return skvm::max(x, y); });
case k_clamp_IntrinsicKind:
return ternary(
[](skvm::F32 x, skvm::F32 lo, skvm::F32 hi) { return skvm::clamp(x, lo, hi); });
case k_saturate_IntrinsicKind:
return unary(args[0], [](skvm::F32 x) { return skvm::clamp01(x); });
case k_mix_IntrinsicKind:
return ternary(
[](skvm::F32 x, skvm::F32 y, skvm::F32 t) { return skvm::lerp(x, y, t); });
case k_step_IntrinsicKind:
return binary([](skvm::F32 edge, skvm::F32 x) { return select(x < edge, 0.0f, 1.0f); });
case k_smoothstep_IntrinsicKind:
return ternary([](skvm::F32 edge0, skvm::F32 edge1, skvm::F32 x) {
skvm::F32 t = skvm::clamp01((x - edge0) / (edge1 - edge0));
return t ** t ** (3 - 2 ** t);
});
case k_length_IntrinsicKind: return skvm::sqrt(dot(args[0], args[0]));
case k_distance_IntrinsicKind: {
Value vec = binary([](skvm::F32 x, skvm::F32 y) { return x - y; });
return skvm::sqrt(dot(vec, vec));
}
case k_dot_IntrinsicKind: return dot(args[0], args[1]);
case k_cross_IntrinsicKind: {
skvm::F32 ax = f32(args[0][0]), ay = f32(args[0][1]), az = f32(args[0][2]),
bx = f32(args[1][0]), by = f32(args[1][1]), bz = f32(args[1][2]);
Value result(3);
result[0] = ay**bz - az**by;
result[1] = az**bx - ax**bz;
result[2] = ax**by - ay**bx;
return result;
}
case k_normalize_IntrinsicKind: {
skvm::F32 invLen = 1.0f / skvm::sqrt(dot(args[0], args[0]));
return unary(args[0], [&](skvm::F32 x) { return x ** invLen; });
}
case k_faceforward_IntrinsicKind: {
const Value &N = args[0],
&I = args[1],
&Nref = args[2];
skvm::F32 dotNrefI = dot(Nref, I);
return unary(N, [&](skvm::F32 n) { return select(dotNrefI<0, n, -n); });
}
case k_reflect_IntrinsicKind: {
const Value &I = args[0],
&N = args[1];
skvm::F32 dotNI = dot(N, I);
return binary([&](skvm::F32 i, skvm::F32 n) {
return i - 2**dotNI**n;
});
}
case k_refract_IntrinsicKind: {
const Value &I = args[0],
&N = args[1];
skvm::F32 eta = f32(args[2]);
skvm::F32 dotNI = dot(N, I),
k = 1 - eta**eta**(1 - dotNI**dotNI);
return binary([&](skvm::F32 i, skvm::F32 n) {
return select(k<0, 0.0f, eta**i - (eta**dotNI + sqrt(k))**n);
});
}
case k_matrixCompMult_IntrinsicKind:
return binary([](skvm::F32 x, skvm::F32 y) { return x ** y; });
case k_inverse_IntrinsicKind: {
switch (args[0].slots()) {
case 4: return this->writeMatrixInverse2x2(args[0]);
case 9: return this->writeMatrixInverse3x3(args[0]);
case 16: return this->writeMatrixInverse4x4(args[0]);
default:
SkDEBUGFAIL("Invalid call to inverse");
return {};
}
}
case k_lessThan_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x < y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x < y; });
case k_lessThanEqual_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x <= y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x <= y; });
case k_greaterThan_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x > y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x > y; });
case k_greaterThanEqual_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x >= y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x >= y; });
case k_equal_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x == y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x == y; });
case k_notEqual_IntrinsicKind:
return nk == Type::NumberKind::kFloat
? binary([](skvm::F32 x, skvm::F32 y) { return x != y; })
: binary([](skvm::I32 x, skvm::I32 y) { return x != y; });
case k_any_IntrinsicKind: {
skvm::I32 result = i32(args[0][0]);
for (size_t i = 1; i < args[0].slots(); ++i) {
result |= i32(args[0][i]);
}
return result;
}
case k_all_IntrinsicKind: {
skvm::I32 result = i32(args[0][0]);
for (size_t i = 1; i < args[0].slots(); ++i) {
result &= i32(args[0][i]);
}
return result;
}
case k_not_IntrinsicKind: return unary(args[0], [](skvm::I32 x) { return ~x; });
case k_toLinearSrgb_IntrinsicKind: {
skvm::Color color = {
f32(args[0][0]), f32(args[0][1]), f32(args[0][2]), fBuilder->splat(1.0f)};
color = fCallbacks->toLinearSrgb(color);
Value result(3);
result[0] = color.r;
result[1] = color.g;
result[2] = color.b;
return result;
}
case k_fromLinearSrgb_IntrinsicKind: {
skvm::Color color = {
f32(args[0][0]), f32(args[0][1]), f32(args[0][2]), fBuilder->splat(1.0f)};
color = fCallbacks->fromLinearSrgb(color);
Value result(3);
result[0] = color.r;
result[1] = color.g;
result[2] = color.b;
return result;
}
default:
SkDEBUGFAILF("unsupported intrinsic %s", c.function().description().c_str());
return {};
}
SkUNREACHABLE;
}
Value SkVMGenerator::writeFunctionCall(const FunctionCall& f) {
if (f.function().isIntrinsic() && !f.function().definition()) {
return this->writeIntrinsicCall(f);
}
const FunctionDeclaration& decl = f.function();
SkASSERTF(decl.definition(), "no definition for function '%s'", decl.description().c_str());
const FunctionDefinition& funcDef = *decl.definition();
// Evaluate all arguments, gather the results into a contiguous list of IDs
std::vector<skvm::Val> argVals;
for (const auto& arg : f.arguments()) {
Value v = this->writeExpression(*arg);
for (size_t i = 0; i < v.slots(); ++i) {
argVals.push_back(v[i]);
}
}
size_t returnSlot;
{
// This merges currentFunction().fReturned into fConditionMask. Lanes that conditionally
// returned in the current function would otherwise resume execution within the child.
ScopedCondition m(this, ~currentFunction().fReturned);
returnSlot = this->writeFunction(funcDef, SkMakeSpan(argVals));
}
// Propagate new values of any 'out' params back to the original arguments
const std::unique_ptr<Expression>* argIter = f.arguments().begin();
size_t valIdx = 0;
for (const Variable* p : decl.parameters()) {
size_t nslots = p->type().slotCount();
if (p->modifiers().fFlags & Modifiers::kOut_Flag) {
Value v(nslots);
for (size_t i = 0; i < nslots; ++i) {
v[i] = argVals[valIdx + i];
}
const std::unique_ptr<Expression>& arg = *argIter;
this->writeStore(*arg, v);
}
valIdx += nslots;
argIter++;
}
// Create a result Value from the return slot
return this->getSlotValue(returnSlot, f.type().slotCount());
}
Value SkVMGenerator::writeExternalFunctionCall(const ExternalFunctionCall& c) {
// Evaluate all arguments, gather the results into a contiguous list of F32
std::vector<skvm::F32> args;
for (const auto& arg : c.arguments()) {
Value v = this->writeExpression(*arg);
for (size_t i = 0; i < v.slots(); ++i) {
args.push_back(f32(v[i]));
}
}
// Create storage for the return value
size_t nslots = c.type().slotCount();
std::vector<skvm::F32> result(nslots, fBuilder->splat(0.0f));
c.function().call(fBuilder, args.data(), result.data(), this->mask());
// Convert from 'vector of F32' to Value
Value resultVal(nslots);
for (size_t i = 0; i < nslots; ++i) {
resultVal[i] = result[i];
}
return resultVal;
}
Value SkVMGenerator::writeLiteral(const Literal& l) {
if (l.type().isFloat()) {
return fBuilder->splat(l.as<Literal>().floatValue());
}
if (l.type().isInteger()) {
return fBuilder->splat(static_cast<int>(l.as<Literal>().intValue()));
}
SkASSERT(l.type().isBoolean());
return fBuilder->splat(l.as<Literal>().boolValue() ? ~0 : 0);
}
Value SkVMGenerator::writePrefixExpression(const PrefixExpression& p) {
Value val = this->writeExpression(*p.operand());
switch (p.getOperator().kind()) {
case Token::Kind::TK_PLUSPLUS:
case Token::Kind::TK_MINUSMINUS: {
bool incr = p.getOperator().kind() == Token::Kind::TK_PLUSPLUS;
switch (base_number_kind(p.type())) {
case Type::NumberKind::kFloat:
val = f32(val) + fBuilder->splat(incr ? 1.0f : -1.0f);
break;
case Type::NumberKind::kSigned:
val = i32(val) + fBuilder->splat(incr ? 1 : -1);
break;
default:
SkASSERT(false);
return {};
}
return this->writeStore(*p.operand(), val);
}
case Token::Kind::TK_MINUS: {
switch (base_number_kind(p.type())) {
case Type::NumberKind::kFloat:
return this->unary(val, [](skvm::F32 x) { return -x; });
case Type::NumberKind::kSigned:
return this->unary(val, [](skvm::I32 x) { return -x; });
default:
SkASSERT(false);
return {};
}
}
case Token::Kind::TK_LOGICALNOT:
case Token::Kind::TK_BITWISENOT:
return this->unary(val, [](skvm::I32 x) { return ~x; });
default:
SkASSERT(false);
return {};
}
}
Value SkVMGenerator::writePostfixExpression(const PostfixExpression& p) {
switch (p.getOperator().kind()) {
case Token::Kind::TK_PLUSPLUS:
case Token::Kind::TK_MINUSMINUS: {
Value old = this->writeExpression(*p.operand()),
val = old;
SkASSERT(val.slots() == 1);
bool incr = p.getOperator().kind() == Token::Kind::TK_PLUSPLUS;
switch (base_number_kind(p.type())) {
case Type::NumberKind::kFloat:
val = f32(val) + fBuilder->splat(incr ? 1.0f : -1.0f);
break;
case Type::NumberKind::kSigned:
val = i32(val) + fBuilder->splat(incr ? 1 : -1);
break;
default:
SkASSERT(false);
return {};
}
this->writeStore(*p.operand(), val);
return old;
}
default:
SkASSERT(false);
return {};
}
}
Value SkVMGenerator::writeSwizzle(const Swizzle& s) {
Value base = this->writeExpression(*s.base());
Value swizzled(s.components().size());
for (size_t i = 0; i < s.components().size(); ++i) {
swizzled[i] = base[s.components()[i]];
}
return swizzled;
}
Value SkVMGenerator::writeTernaryExpression(const TernaryExpression& t) {
skvm::I32 test = i32(this->writeExpression(*t.test()));
Value ifTrue, ifFalse;
{
ScopedCondition m(this, test);
ifTrue = this->writeExpression(*t.ifTrue());
}
{
ScopedCondition m(this, ~test);
ifFalse = this->writeExpression(*t.ifFalse());
}
size_t nslots = ifTrue.slots();
SkASSERT(nslots == ifFalse.slots());
Value result(nslots);
for (size_t i = 0; i < nslots; ++i) {
result[i] = skvm::select(test, i32(ifTrue[i]), i32(ifFalse[i]));
}
return result;
}
Value SkVMGenerator::writeExpression(const Expression& e) {
switch (e.kind()) {
case Expression::Kind::kBinary:
return this->writeBinaryExpression(e.as<BinaryExpression>());
case Expression::Kind::kChildCall:
return this->writeChildCall(e.as<ChildCall>());
case Expression::Kind::kConstructorArray:
case Expression::Kind::kConstructorCompound:
case Expression::Kind::kConstructorStruct:
return this->writeAggregationConstructor(e.asAnyConstructor());
case Expression::Kind::kConstructorArrayCast:
return this->writeExpression(*e.as<ConstructorArrayCast>().argument());
case Expression::Kind::kConstructorDiagonalMatrix:
return this->writeConstructorDiagonalMatrix(e.as<ConstructorDiagonalMatrix>());
case Expression::Kind::kConstructorMatrixResize:
return this->writeConstructorMatrixResize(e.as<ConstructorMatrixResize>());
case Expression::Kind::kConstructorScalarCast:
case Expression::Kind::kConstructorCompoundCast:
return this->writeConstructorCast(e.asAnyConstructor());
case Expression::Kind::kConstructorSplat:
return this->writeConstructorSplat(e.as<ConstructorSplat>());
case Expression::Kind::kFieldAccess:
return this->writeFieldAccess(e.as<FieldAccess>());
case Expression::Kind::kIndex:
return this->writeIndexExpression(e.as<IndexExpression>());
case Expression::Kind::kVariableReference:
return this->writeVariableExpression(e.as<VariableReference>());
case Expression::Kind::kLiteral:
return this->writeLiteral(e.as<Literal>());
case Expression::Kind::kFunctionCall:
return this->writeFunctionCall(e.as<FunctionCall>());
case Expression::Kind::kExternalFunctionCall:
return this->writeExternalFunctionCall(e.as<ExternalFunctionCall>());
case Expression::Kind::kPrefix:
return this->writePrefixExpression(e.as<PrefixExpression>());
case Expression::Kind::kPostfix:
return this->writePostfixExpression(e.as<PostfixExpression>());
case Expression::Kind::kSwizzle:
return this->writeSwizzle(e.as<Swizzle>());
case Expression::Kind::kTernary:
return this->writeTernaryExpression(e.as<TernaryExpression>());
case Expression::Kind::kExternalFunctionReference:
default:
SkDEBUGFAIL("Unsupported expression");
return {};
}
}
Value SkVMGenerator::writeStore(const Expression& lhs, const Value& rhs) {
SkASSERTF(rhs.slots() == lhs.type().slotCount(),
"lhs=%s (%s)\nrhs=%zu slot",
lhs.type().description().c_str(), lhs.description().c_str(), rhs.slots());
// We need to figure out the collection of slots that we're storing into. The l-value (lhs)
// is always a VariableReference, possibly wrapped by one or more Swizzle, FieldAccess, or
// IndexExpressions. The underlying VariableReference has a range of slots for its storage,
// and each expression wrapped around that selects a sub-set of those slots (Field/Index),
// or rearranges them (Swizzle).
SkSTArray<4, size_t, true> slots;
slots.resize(rhs.slots());
// Start with the identity slot map - this basically says that the values from rhs belong in
// slots [0, 1, 2 ... N] of the lhs.
for (size_t i = 0; i < slots.size(); ++i) {
slots[i] = i;
}
// Now, as we peel off each outer expression, adjust 'slots' to be the locations relative to
// the next (inner) expression:
const Expression* expr = &lhs;
while (!expr->is<VariableReference>()) {
switch (expr->kind()) {
case Expression::Kind::kFieldAccess: {
const FieldAccess& fld = expr->as<FieldAccess>();
size_t offset = this->fieldSlotOffset(fld);
for (size_t& s : slots) {
s += offset;
}
expr = fld.base().get();
} break;
case Expression::Kind::kIndex: {
const IndexExpression& idx = expr->as<IndexExpression>();
size_t offset = this->indexSlotOffset(idx);
for (size_t& s : slots) {
s += offset;
}
expr = idx.base().get();
} break;
case Expression::Kind::kSwizzle: {
const Swizzle& swz = expr->as<Swizzle>();
for (size_t& s : slots) {
s = swz.components()[s];
}
expr = swz.base().get();
} break;
default:
// No other kinds of expressions are valid in lvalues. (see Analysis::IsAssignable)
SkDEBUGFAIL("Invalid expression type");
return {};
}
}
// When we get here, 'slots' are all relative to the first slot holding 'var's storage
const Variable& var = *expr->as<VariableReference>().variable();
size_t varSlot = this->getSlot(var);
for (size_t& slot : slots) {
SkASSERT(slot < var.type().slotCount());
slot += varSlot;
}
// `slots` are now absolute indices into `fSlots`.
skvm::I32 mask = this->mask();
for (size_t i = 0; i < rhs.slots(); ++i) {
int slotNum = slots[i];
skvm::Val conditionalStore = this->writeConditionalStore(fSlots[slotNum].val, rhs[i], mask);
this->writeToSlot(slotNum, conditionalStore);
}
return rhs;
}
skvm::Val SkVMGenerator::writeConditionalStore(skvm::Val lhs, skvm::Val rhs, skvm::I32 mask) {
return select(mask, f32(rhs), f32(lhs)).id;
}
void SkVMGenerator::writeBlock(const Block& b) {
skvm::I32 mask = this->mask();
this->emitTraceScope(mask, +1);
for (const std::unique_ptr<Statement>& stmt : b.children()) {
this->writeStatement(*stmt);
}
this->emitTraceScope(mask, -1);
}
void SkVMGenerator::writeBreakStatement() {
// Any active lanes stop executing for the duration of the current loop
fLoopMask &= ~this->mask();
}
void SkVMGenerator::writeContinueStatement() {
// Any active lanes stop executing for the current iteration.
// Remember them in fContinueMask, to be re-enabled later.
skvm::I32 mask = this->mask();
fLoopMask &= ~mask;
fContinueMask |= mask;
}
void SkVMGenerator::writeForStatement(const ForStatement& f) {
// We require that all loops be ES2-compliant (unrollable), and actually unroll them here
SkASSERT(f.unrollInfo());
const LoopUnrollInfo& loop = *f.unrollInfo();
SkASSERT(loop.fIndex->type().slotCount() == 1);
size_t indexSlot = this->getSlot(*loop.fIndex);
double val = loop.fStart;
const skvm::I32 zero = fBuilder->splat(0);
skvm::I32 oldLoopMask = fLoopMask,
oldContinueMask = fContinueMask;
const Type::NumberKind indexKind = base_number_kind(loop.fIndex->type());
// We want the loop index to disappear at the end of the loop, so wrap the for statement in a
// trace scope.
if (loop.fCount > 0) {
skvm::I32 mask = this->mask();
this->emitTraceScope(mask, +1);
for (int i = 0; i < loop.fCount; ++i) {
this->writeToSlot(indexSlot, (indexKind == Type::NumberKind::kFloat)
? fBuilder->splat(static_cast<float>(val)).id
: fBuilder->splat(static_cast<int>(val)).id);
fContinueMask = zero;
this->writeStatement(*f.statement());
fLoopMask |= fContinueMask;
this->emitTraceLine(f.test() ? f.test()->fLine : f.fLine);
val += loop.fDelta;
}
this->emitTraceScope(mask, -1);
}
fLoopMask = oldLoopMask;
fContinueMask = oldContinueMask;
}
void SkVMGenerator::writeIfStatement(const IfStatement& i) {
Value test = this->writeExpression(*i.test());
{
ScopedCondition ifTrue(this, i32(test));
this->writeStatement(*i.ifTrue());
}
if (i.ifFalse()) {
ScopedCondition ifFalse(this, ~i32(test));
this->writeStatement(*i.ifFalse());
}
}
void SkVMGenerator::writeReturnStatement(const ReturnStatement& r) {
skvm::I32 returnsHere = this->mask();
if (r.expression()) {
Value val = this->writeExpression(*r.expression());
size_t slot = currentFunction().fReturnSlot;
size_t nslots = r.expression()->type().slotCount();
for (size_t i = 0; i < nslots; ++i) {
fSlots[slot + i].writtenTo = false;
skvm::Val conditionalStore = this->writeConditionalStore(fSlots[slot + i].val, val[i],
returnsHere);
this->writeToSlot(slot + i, conditionalStore);
}
}
currentFunction().fReturned |= returnsHere;
}
void SkVMGenerator::writeSwitchStatement(const SwitchStatement& s) {
skvm::I32 falseValue = fBuilder->splat( 0);
skvm::I32 trueValue = fBuilder->splat(~0);
// Create a "switchFallthough" scratch variable, initialized to false.
skvm::I32 switchFallthrough = falseValue;
// Loop masks behave just like for statements. When a break is encountered, it masks off all
// lanes for the rest of the body of the switch.
skvm::I32 oldLoopMask = fLoopMask;
Value switchValue = this->writeExpression(*s.value());
for (const std::unique_ptr<Statement>& stmt : s.cases()) {
const SwitchCase& c = stmt->as<SwitchCase>();
if (!c.isDefault()) {
Value caseValue = fBuilder->splat((int) c.value());
// We want to execute this switch case if we're falling through from a previous case, or
// if the case value matches.
ScopedCondition conditionalCaseBlock(
this,
switchFallthrough | (i32(caseValue) == i32(switchValue)));
this->writeStatement(*c.statement());
// If we are inside the case block, we set the fallthrough flag to true (`break` still
// works to stop the flow of execution regardless, since it zeroes out the loop-mask).
switchFallthrough.id = this->writeConditionalStore(switchFallthrough.id, trueValue.id,
this->mask());
} else {
// This is the default case. Since it's always last, we can just dump in the code.
this->writeStatement(*c.statement());
}
}
// Restore state.
fLoopMask = oldLoopMask;
}
void SkVMGenerator::writeVarDeclaration(const VarDeclaration& decl) {
size_t slot = this->getSlot(decl.var()),
nslots = decl.var().type().slotCount();
Value val = decl.value() ? this->writeExpression(*decl.value()) : Value{};
for (size_t i = 0; i < nslots; ++i) {
fSlots[slot + i].writtenTo = false;
this->writeToSlot(slot + i, val ? val[i] : fBuilder->splat(0.0f).id);
}
}
void SkVMGenerator::emitTraceLine(int line) {
if (fDebugTrace && line > 0) {
fBuilder->trace_line(fTraceHookID, this->mask(), fTraceMask, line);
}
}
void SkVMGenerator::emitTraceScope(skvm::I32 executionMask, int delta) {
if (fDebugTrace) {
fBuilder->trace_scope(fTraceHookID, executionMask, fTraceMask, delta);
}
}
void SkVMGenerator::writeStatement(const Statement& s) {
this->emitTraceLine(s.fLine);
switch (s.kind()) {
case Statement::Kind::kBlock:
this->writeBlock(s.as<Block>());
break;
case Statement::Kind::kBreak:
this->writeBreakStatement();
break;
case Statement::Kind::kContinue:
this->writeContinueStatement();
break;
case Statement::Kind::kExpression:
this->writeExpression(*s.as<ExpressionStatement>().expression());
break;
case Statement::Kind::kFor:
this->writeForStatement(s.as<ForStatement>());
break;
case Statement::Kind::kIf:
this->writeIfStatement(s.as<IfStatement>());
break;
case Statement::Kind::kReturn:
this->writeReturnStatement(s.as<ReturnStatement>());
break;
case Statement::Kind::kSwitch:
this->writeSwitchStatement(s.as<SwitchStatement>());
break;
case Statement::Kind::kVarDeclaration:
this->writeVarDeclaration(s.as<VarDeclaration>());
break;
case Statement::Kind::kDiscard:
case Statement::Kind::kDo:
SkDEBUGFAIL("Unsupported control flow");
break;
case Statement::Kind::kInlineMarker:
case Statement::Kind::kNop:
break;
default:
SkDEBUGFAIL("Unrecognized statement");
break;
}
}
skvm::Color ProgramToSkVM(const Program& program,
const FunctionDefinition& function,
skvm::Builder* builder,
SkVMDebugTrace* debugTrace,
SkSpan<skvm::Val> uniforms,
skvm::Coord device,
skvm::Coord local,
skvm::Color inputColor,
skvm::Color destColor,
SkVMCallbacks* callbacks) {
skvm::Val zero = builder->splat(0.0f).id;
skvm::Val result[4] = {zero,zero,zero,zero};
skvm::Val args[8]; // At most 8 arguments (half4 srcColor, half4 dstColor)
size_t argSlots = 0;
for (const SkSL::Variable* param : function.declaration().parameters()) {
switch (param->modifiers().fLayout.fBuiltin) {
case SK_MAIN_COORDS_BUILTIN:
SkASSERT(param->type().slotCount() == 2);
SkASSERT((argSlots + 2) <= SK_ARRAY_COUNT(args));
args[argSlots++] = local.x.id;
args[argSlots++] = local.y.id;
break;
case SK_INPUT_COLOR_BUILTIN:
SkASSERT(param->type().slotCount() == 4);
SkASSERT((argSlots + 4) <= SK_ARRAY_COUNT(args));
args[argSlots++] = inputColor.r.id;
args[argSlots++] = inputColor.g.id;
args[argSlots++] = inputColor.b.id;
args[argSlots++] = inputColor.a.id;
break;
case SK_DEST_COLOR_BUILTIN:
SkASSERT(param->type().slotCount() == 4);
SkASSERT((argSlots + 4) <= SK_ARRAY_COUNT(args));
args[argSlots++] = destColor.r.id;
args[argSlots++] = destColor.g.id;
args[argSlots++] = destColor.b.id;
args[argSlots++] = destColor.a.id;
break;
default:
SkDEBUGFAIL("Invalid parameter to main()");
return {};
}
}
SkASSERT(argSlots <= SK_ARRAY_COUNT(args));
// Make sure that the SkVMDebugTrace starts from a clean slate.
if (debugTrace) {
debugTrace->fSlotInfo.clear();
debugTrace->fFuncInfo.clear();
debugTrace->fTraceInfo.clear();
}
SkVMGenerator generator(program, builder, debugTrace, callbacks);
generator.writeProgram(uniforms, device, function, {args, argSlots}, SkMakeSpan(result));
return skvm::Color{{builder, result[0]},
{builder, result[1]},
{builder, result[2]},
{builder, result[3]}};
}
bool ProgramToSkVM(const Program& program,
const FunctionDefinition& function,
skvm::Builder* b,
SkVMDebugTrace* debugTrace,
SkSpan<skvm::Val> uniforms,
SkVMSignature* outSignature) {
SkVMSignature ignored,
*signature = outSignature ? outSignature : &ignored;
std::vector<skvm::Ptr> argPtrs;
std::vector<skvm::Val> argVals;
for (const Variable* p : function.declaration().parameters()) {
size_t slots = p->type().slotCount();
signature->fParameterSlots += slots;
for (size_t i = 0; i < slots; ++i) {
argPtrs.push_back(b->varying<float>());
argVals.push_back(b->loadF(argPtrs.back()).id);
}
}
std::vector<skvm::Ptr> returnPtrs;
std::vector<skvm::Val> returnVals;
signature->fReturnSlots = function.declaration().returnType().slotCount();
for (size_t i = 0; i < signature->fReturnSlots; ++i) {
returnPtrs.push_back(b->varying<float>());
returnVals.push_back(b->splat(0.0f).id);
}
class Callbacks : public SkVMCallbacks {
public:
Callbacks(skvm::Color color) : fColor(color) {}
skvm::Color sampleShader(int, skvm::Coord) override {
fUsedUnsupportedFeatures = true;
return fColor;
}
skvm::Color sampleColorFilter(int, skvm::Color) override {
fUsedUnsupportedFeatures = true;
return fColor;
}
skvm::Color sampleBlender(int, skvm::Color, skvm::Color) override {
fUsedUnsupportedFeatures = true;
return fColor;
}
skvm::Color toLinearSrgb(skvm::Color) override {
fUsedUnsupportedFeatures = true;
return fColor;
}
skvm::Color fromLinearSrgb(skvm::Color) override {
fUsedUnsupportedFeatures = true;
return fColor;
}
bool fUsedUnsupportedFeatures = false;
const skvm::Color fColor;
};
// Set up device coordinates so that the rightmost evaluated pixel will be centered on (0, 0).
// (If the coordinates aren't used, dead-code elimination will optimize this away.)
skvm::F32 pixelCenter = b->splat(0.5f);
skvm::Coord device = {pixelCenter, pixelCenter};
device.x += to_F32(b->splat(1) - b->index());
skvm::F32 zero = b->splat(0.0f);
skvm::Color sampledColor{zero, zero, zero, zero};
Callbacks callbacks(sampledColor);
SkVMGenerator generator(program, b, debugTrace, &callbacks);
generator.writeProgram(uniforms, device, function, SkMakeSpan(argVals), SkMakeSpan(returnVals));
// If the SkSL tried to use any shader, colorFilter, or blender objects - we don't have a
// mechanism (yet) for binding to those.
if (callbacks.fUsedUnsupportedFeatures) {
return false;
}
// generateCode has updated the contents of 'argVals' for any 'out' or 'inout' parameters.
// Propagate those changes back to our varying buffers:
size_t argIdx = 0;
for (const Variable* p : function.declaration().parameters()) {
size_t nslots = p->type().slotCount();
if (p->modifiers().fFlags & Modifiers::kOut_Flag) {
for (size_t i = 0; i < nslots; ++i) {
b->storeF(argPtrs[argIdx + i], skvm::F32{b, argVals[argIdx + i]});
}
}
argIdx += nslots;
}
// It's also updated the contents of 'returnVals' with the return value of the entry point.
// Store that as well:
for (size_t i = 0; i < signature->fReturnSlots; ++i) {
b->storeF(returnPtrs[i], skvm::F32{b, returnVals[i]});
}
return true;
}
const FunctionDefinition* Program_GetFunction(const Program& program, const char* function) {
for (const ProgramElement* e : program.elements()) {
if (e->is<FunctionDefinition>() &&
e->as<FunctionDefinition>().declaration().name() == function) {
return &e->as<FunctionDefinition>();
}
}
return nullptr;
}
static void gather_uniforms(UniformInfo* info, const Type& type, const String& name) {
switch (type.typeKind()) {
case Type::TypeKind::kStruct:
for (const auto& f : type.fields()) {
gather_uniforms(info, *f.fType, name + "." + f.fName);
}
break;
case Type::TypeKind::kArray:
for (int i = 0; i < type.columns(); ++i) {
gather_uniforms(info, type.componentType(),
String::printf("%s[%d]", name.c_str(), i));
}
break;
case Type::TypeKind::kScalar:
case Type::TypeKind::kVector:
case Type::TypeKind::kMatrix:
info->fUniforms.push_back({name, base_number_kind(type), type.rows(), type.columns(),
info->fUniformSlotCount});
info->fUniformSlotCount += type.columns() * type.rows();
break;
default:
break;
}
}
std::unique_ptr<UniformInfo> Program_GetUniformInfo(const Program& program) {
auto info = std::make_unique<UniformInfo>();
for (const ProgramElement* e : program.elements()) {
if (!e->is<GlobalVarDeclaration>()) {
continue;
}
const GlobalVarDeclaration& decl = e->as<GlobalVarDeclaration>();
const Variable& var = decl.declaration()->as<VarDeclaration>().var();
if (var.modifiers().fFlags & Modifiers::kUniform_Flag) {
gather_uniforms(info.get(), var.type(), String(var.name()));
}
}
return info;
}