From c6a19f1d044e4e23d3f0a608aa91da55376512bf Mon Sep 17 00:00:00 2001
From: Ethan Nicholas <ethannicholas@google.com>
Date: Thu, 29 Mar 2018 16:46:56 -0400
Subject: [PATCH] fix for frexp dataflow analysis

Bug: skia:
Change-Id: Ic20bedadfbf37fd78ce03872ece2d9552307cfcd
Reviewed-on: https://skia-review.googlesource.com/117243
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
---
 src/sksl/SkSLCompiler.cpp | 13 +++++++++++++
 src/sksl/sksl.inc         |  2 +-
 tests/SkSLGLSLTest.cpp    | 17 +++++++++++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/sksl/SkSLCompiler.cpp b/src/sksl/SkSLCompiler.cpp
index 4650e5c643..7db9440e7f 100644
--- a/src/sksl/SkSLCompiler.cpp
+++ b/src/sksl/SkSLCompiler.cpp
@@ -17,6 +17,7 @@
 #include "ir/SkSLEnum.h"
 #include "ir/SkSLExpression.h"
 #include "ir/SkSLExpressionStatement.h"
+#include "ir/SkSLFunctionCall.h"
 #include "ir/SkSLIntLiteral.h"
 #include "ir/SkSLModifiersDeclaration.h"
 #include "ir/SkSLNop.h"
@@ -291,6 +292,18 @@ void Compiler::addDefinitions(const BasicBlock::Node& node,
                     }
                     break;
                 }
+                case Expression::kFunctionCall_Kind: {
+                    const FunctionCall& c = (const FunctionCall&) *expr;
+                    for (size_t i = 0; i < c.fFunction.fParameters.size(); ++i) {
+                        if (c.fFunction.fParameters[i]->fModifiers.fFlags & Modifiers::kOut_Flag) {
+                            this->addDefinition(
+                                      c.fArguments[i].get(),
+                                      (std::unique_ptr<Expression>*) &fContext->fDefined_Expression,
+                                      definitions);
+                        }
+                    }
+                    break;
+                }
                 case Expression::kPrefix_Kind: {
                     const PrefixExpression* p = (PrefixExpression*) expr;
                     if (p->fOperator == Token::MINUSMINUS || p->fOperator == Token::PLUSPLUS) {
diff --git a/src/sksl/sksl.inc b/src/sksl/sksl.inc
index 2b433ebd0f..0d38e73af6 100644
--- a/src/sksl/sksl.inc
+++ b/src/sksl/sksl.inc
@@ -102,7 +102,7 @@ $genType fma($genType a, $genType b, $genType c);
 $genHType fma($genHType a, $genHType b, $genHType c);
 $genDType fma($genDType a, $genDType b, $genDType c);
 //$genDType fma($genDType a, $genDType b, $genDType c);
-$genType frexp($genType x, out $genIType exp);
+sk_has_side_effects $genType frexp($genType x, out $genIType exp);
 //$genDType frexp($genDType x, out $genIType exp);
 $genType ldexp($genType x, in $genIType exp);
 //$genDType ldexp($genDType x, in $genIType exp);
diff --git a/tests/SkSLGLSLTest.cpp b/tests/SkSLGLSLTest.cpp
index 27797b6189..0b9ed35006 100644
--- a/tests/SkSLGLSLTest.cpp
+++ b/tests/SkSLGLSLTest.cpp
@@ -1945,4 +1945,21 @@ DEF_TEST(SkSLIncompleteShortIntPrecision, r) {
          SkSL::Program::kFragment_Kind);
 }
 
+DEF_TEST(SkSLFrExp, r) {
+    test(r,
+         "void main() {"
+         "    int exp;"
+         "    float foo = frexp(0.5, exp);"
+         "    sk_FragColor = float4(exp);"
+         "}",
+         *SkSL::ShaderCapsFactory::Default(),
+         "#version 400\n"
+         "out vec4 sk_FragColor;\n"
+         "void main() {\n"
+         "    int exp;\n"
+         "    float foo = frexp(0.5, exp);\n"
+         "    sk_FragColor = vec4(float(exp));\n"
+         "}\n");
+}
+
 #endif