commit ffba524ff800628fb550ba555157f3b2cde1d37e
author John Stiles <johnstiles@google.com> Fri May 07 10:50:22 2021 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Fri May 07 17:03:38 2021 +0000
tree 2a3422e1c80e542b8ddaa357c749772a91fff66c
parent 062793401d1f0f3b0254288c79aa6769c710b6cc

Add variation of GetConstantValueForVariable which handles ownership.

The new function `MakeConstantValueForVariable` behaves the same, except
it takes unique_ptrs as inputs and returns a unique_ptr as output.
We already had this behavior coded up in two places and I realized I
could use this functionality in other spots as well.

Change-Id: I2f0c43e8555a3c89bf9a1eef7030b422355ec2a3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/405680
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

src/sksl/SkSLConstantFolder.cpp

diff --git a/src/sksl/SkSLConstantFolder.cpp b/src/sksl/SkSLConstantFolder.cpp
index 6573d3f..83d4ebb 100644
--- a/src/sksl/SkSLConstantFolder.cpp
+++ b/src/sksl/SkSLConstantFolder.cpp
@@ -233,6 +233,15 @@
     return &inExpr;
 }
 
+std::unique_ptr<Expression> ConstantFolder::MakeConstantValueForVariable(
+        std::unique_ptr<Expression> expr) {
+    const Expression* constantExpr = GetConstantValueForVariable(*expr);
+    if (constantExpr != expr.get()) {
+        expr = constantExpr->clone();
+    }
+    return expr;
+}
+
 static std::unique_ptr<Expression> simplify_no_op_arithmetic(const Context& context,
                                                              const Expression& left,
                                                              Operator op,

src/sksl/SkSLConstantFolder.h

diff --git a/src/sksl/SkSLConstantFolder.h b/src/sksl/SkSLConstantFolder.h
index d82f3a3..992030a 100644
--- a/src/sksl/SkSLConstantFolder.h
+++ b/src/sksl/SkSLConstantFolder.h
@@ -44,6 +44,13 @@
     static const Expression* GetConstantValueForVariable(const Expression& value);
 
     /**
+     * If the expression is a const variable with a known compile-time-constant value, returns a
+     * clone of that value. If not, returns the original expression as-is.
+     */
+    static std::unique_ptr<Expression> MakeConstantValueForVariable(
+            std::unique_ptr<Expression> expr);
+
+    /**
      * Reports an error and returns true if op is a division / mod operator and right is zero or
      * contains a zero element.
      */

src/sksl/ir/SkSLConstructorCompound.cpp

diff --git a/src/sksl/ir/SkSLConstructorCompound.cpp b/src/sksl/ir/SkSLConstructorCompound.cpp
index 834c9d3..0560044 100644
--- a/src/sksl/ir/SkSLConstructorCompound.cpp
+++ b/src/sksl/ir/SkSLConstructorCompound.cpp
@@ -76,10 +76,7 @@
         // Replace constant variables with their corresponding values, so `float2(one, two)` can
         // compile down to `float2(1.0, 2.0)` (the latter is a compile-time constant).
         for (std::unique_ptr<Expression>& arg : args) {
-            const Expression* value = ConstantFolder::GetConstantValueForVariable(*arg);
-            if (value != arg.get()) {
-                arg = value->clone();
-            }
+            arg = ConstantFolder::MakeConstantValueForVariable(std::move(arg));
         }
     }
 

src/sksl/ir/SkSLConstructorSplat.cpp

diff --git a/src/sksl/ir/SkSLConstructorSplat.cpp b/src/sksl/ir/SkSLConstructorSplat.cpp
index 669dcd1..41451c1 100644
--- a/src/sksl/ir/SkSLConstructorSplat.cpp
+++ b/src/sksl/ir/SkSLConstructorSplat.cpp
@@ -25,10 +25,7 @@
     if (context.fConfig->fSettings.fOptimize) {
         // Replace constant variables with their corresponding values, so `float3(five)` can
         // compile down to `float3(5.0)` (the latter is a compile-time constant).
-        const Expression* value = ConstantFolder::GetConstantValueForVariable(*arg);
-        if (value != arg.get()) {
-            arg = value->clone();
-        }
+        arg = ConstantFolder::MakeConstantValueForVariable(std::move(arg));
     }
 
     SkASSERT(type.isVector());