Work around abs() issue in Intel Mac drivers

include/GLSLANG/ShaderLang.h

@@ -49,7 +49,7 @@ typedef unsigned int GLenum;
 
 // Version number for shader translation API.
 // It is incremented every time the API changes.
-#define ANGLE_SH_VERSION 156
+#define ANGLE_SH_VERSION 157
 
 typedef enum {
     SH_GLES2_SPEC,
@@ -210,6 +210,10 @@ typedef enum {
     // This flag works around an issue in translating GLSL function texelFetchOffset on
     // INTEL drivers. It works by translating texelFetchOffset into texelFetch.
     SH_REWRITE_TEXELFETCHOFFSET_TO_TEXELFETCH = 0x4000000,
+
+    // This flag works around bug in Intel Mac drivers related to abs(i) where
+    // i is an integer.
+    SH_EMULATE_ABS_INT_FUNCTION = 0x8000000,
 } ShCompileOptions;
 
 // Defines alternate strategies for implementing array index clamping.

src/compiler/translator/BuiltInFunctionEmulatorGLSL.cpp

@@ -11,6 +11,16 @@
 #include "compiler/translator/SymbolTable.h"
 #include "compiler/translator/VersionGLSL.h"
 
+void InitBuiltInAbsFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu,
+                                                      sh::GLenum shaderType)
+{
+    if (shaderType == GL_VERTEX_SHADER)
+    {
+        const TType *int1 = TCache::getType(EbtInt);
+        emu->addEmulatedFunction(EOpAbs, int1, "int webgl_abs_emu(int x) { return x * sign(x); }");
+    }
+}
+
 void InitBuiltInFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu, sh::GLenum shaderType)
 {
     // we use macros here instead of function definitions to work around more GLSL

src/compiler/translator/BuiltInFunctionEmulatorGLSL.h

@@ -12,6 +12,12 @@
 class BuiltInFunctionEmulator;
 
 //
+// This works around bug in Intel Mac drivers.
+//
+void InitBuiltInAbsFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu,
+                                                      sh::GLenum shaderType);
+
+//
 // This is only a workaround for OpenGL driver bugs, and isn't needed in general.
 //
 void InitBuiltInFunctionEmulatorForGLSLWorkarounds(BuiltInFunctionEmulator *emu, sh::GLenum shaderType);

src/compiler/translator/TranslatorGLSL.cpp

@@ -22,6 +22,10 @@ TranslatorGLSL::TranslatorGLSL(sh::GLenum type,
 
 void TranslatorGLSL::initBuiltInFunctionEmulator(BuiltInFunctionEmulator *emu, int compileOptions)
 {
+    if (compileOptions & SH_EMULATE_ABS_INT_FUNCTION)
+    {
+        InitBuiltInAbsFunctionEmulatorForGLSLWorkarounds(emu, getShaderType());
+    }
     if (compileOptions & SH_EMULATE_BUILT_IN_FUNCTIONS)
     {
         InitBuiltInFunctionEmulatorForGLSLWorkarounds(emu, getShaderType());