Use ImmutableString for HLSL texture references

src/compiler.gypi

@@ -71,7 +71,10 @@
             'compiler/translator/FoldExpressions.h',
             'compiler/translator/HashNames.cpp',
             'compiler/translator/HashNames.h',
+            'compiler/translator/ImmutableString.cpp',
             'compiler/translator/ImmutableString.h',
+            'compiler/translator/ImmutableStringBuilder.cpp',
+            'compiler/translator/ImmutableStringBuilder.h',
             'compiler/translator/InfoSink.cpp',
             'compiler/translator/InfoSink.h',
             'compiler/translator/Initialize.cpp',

src/compiler/translator/ImmutableString.cpp

+//
+// Copyright (c) 2018 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// ImmutableString.cpp: Wrapper for static or pool allocated char arrays, that are guaranteed to be
+// valid and unchanged for the duration of the compilation.
+//
+
+#include "compiler/translator/ImmutableString.h"
+
+std::ostream &operator<<(std::ostream &os, const sh::ImmutableString &str)
+{
+    return os.write(str.data(), str.length());
+}

src/compiler/translator/ImmutableString.h

@@ -45,10 +45,13 @@ class ImmutableString
     {
     }
 
+    constexpr ImmutableString(const char *data, size_t length) : mData(data), mLength(length) {}
+
     ImmutableString(const ImmutableString &) = default;
     ImmutableString &operator=(const ImmutableString &) = default;
 
     const char *data() const { return mData ? mData : ""; }
+    size_t length() const { return mLength; }
 
     bool operator<(const ImmutableString &b) const
     {
@@ -64,10 +67,12 @@ class ImmutableString
     }
 
   private:
-    const char *const mData;
-    const size_t mLength;
+    const char *mData;
+    size_t mLength;
 };
 
 }  // namespace sh
 
+std::ostream &operator<<(std::ostream &os, const sh::ImmutableString &str);
+
 #endif  // COMPILER_TRANSLATOR_IMMUTABLESTRING_H_

src/compiler/translator/ImmutableStringBuilder.cpp

+//
+// Copyright (c) 2018 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// ImmutableStringBuilder.cpp: Stringstream-like utility for building pool allocated strings where
+// the maximum length is known in advance.
+//
+
+#include "compiler/translator/ImmutableStringBuilder.h"
+
+namespace sh
+{
+
+ImmutableStringBuilder &ImmutableStringBuilder::operator<<(const ImmutableString &str)
+{
+    ASSERT(mData != nullptr);
+    ASSERT(mPos + str.length() <= mMaxLength);
+    memcpy(mData + mPos, str.data(), str.length());
+    mPos += str.length();
+    return *this;
+}
+
+ImmutableStringBuilder &ImmutableStringBuilder::operator<<(const char *str)
+{
+    ASSERT(mData != nullptr);
+    size_t len = strlen(str);
+    ASSERT(mPos + len <= mMaxLength);
+    memcpy(mData + mPos, str, len);
+    mPos += len;
+    return *this;
+}
+
+ImmutableStringBuilder &ImmutableStringBuilder::operator<<(const char &c)
+{
+    ASSERT(mData != nullptr);
+    ASSERT(mPos + 1 <= mMaxLength);
+    mData[mPos++] = c;
+    return *this;
+}
+
+ImmutableStringBuilder::operator ImmutableString()
+{
+    mData[mPos] = '\0';
+    ImmutableString str(static_cast<const char *>(mData), mPos);
+#if defined(ANGLE_ENABLE_ASSERTS)
+    // Make sure that nothing is added to the string after it is finalized.
+    mData = nullptr;
+#endif
+    return str;
+}
+
+}  // namespace sh

src/compiler/translator/ImmutableStringBuilder.h

+//
+// Copyright (c) 2018 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// ImmutableStringBuilder.h: Stringstream-like utility for building pool allocated strings where the
+// maximum length is known in advance.
+//
+
+#ifndef COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_
+#define COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_
+
+#include "compiler/translator/ImmutableString.h"
+
+namespace sh
+{
+
+class ImmutableStringBuilder
+{
+  public:
+    ImmutableStringBuilder(size_t maxLength)
+        : mPos(0u), mMaxLength(maxLength), mData(AllocateEmptyPoolCharArray(maxLength))
+    {
+    }
+
+    ImmutableStringBuilder &operator<<(const ImmutableString &str);
+
+    ImmutableStringBuilder &operator<<(const char *str);
+
+    ImmutableStringBuilder &operator<<(const char &c);
+
+    // This invalidates the ImmutableStringBuilder, so it should only be called once.
+    operator ImmutableString();
+
+  private:
+    inline static char *AllocateEmptyPoolCharArray(size_t strLength)
+    {
+        size_t requiredSize = strLength + 1u;
+        return reinterpret_cast<char *>(GetGlobalPoolAllocator()->allocate(requiredSize));
+    }
+
+    size_t mPos;
+    size_t mMaxLength;
+    char *mData;
+};
+
+}  // namespace sh
+
+#endif  // COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_

src/compiler/translator/TextureFunctionHLSL.cpp

@@ -11,6 +11,7 @@
 
 #include "compiler/translator/TextureFunctionHLSL.h"
 
+#include "compiler/translator/ImmutableStringBuilder.h"
 #include "compiler/translator/UtilsHLSL.h"
 
 namespace sh
@@ -104,8 +105,8 @@ void OutputIntTexCoordWraps(TInfoSinkBase &out,
 
 void OutputHLSL4SampleFunctionPrefix(TInfoSinkBase &out,
                                      const TextureFunctionHLSL::TextureFunction &textureFunction,
-                                     const TString &textureReference,
-                                     const TString &samplerReference)
+                                     const ImmutableString &textureReference,
+                                     const ImmutableString &samplerReference)
 {
     out << textureReference;
     if (IsIntegerSampler(textureFunction.sampler) ||
@@ -450,37 +451,56 @@ void OutputTextureFunctionArgumentList(TInfoSinkBase &out,
 void GetTextureReference(TInfoSinkBase &out,
                          const TextureFunctionHLSL::TextureFunction &textureFunction,
                          const ShShaderOutput outputType,
-                         TString *textureReference,
-                         TString *samplerReference)
+                         ImmutableString *textureReference,
+                         ImmutableString *samplerReference)
 {
     if (outputType == SH_HLSL_4_1_OUTPUT)
     {
-        TString suffix = TextureGroupSuffix(textureFunction.sampler);
+        static const ImmutableString kTexturesStr("textures");
+        static const ImmutableString kSamplersStr("samplers");
+        static const ImmutableString kSamplerIndexStr("[samplerIndex]");
+        static const ImmutableString kTextureIndexStr("[textureIndex]");
+        static const ImmutableString kSamplerArrayIndexStr("[samplerArrayIndex]");
+        ImmutableString suffix(TextureGroupSuffix(textureFunction.sampler));
+
         if (TextureGroup(textureFunction.sampler) == HLSL_TEXTURE_2D)
         {
-            *textureReference = TString("textures") + suffix + "[samplerIndex]";
-            *samplerReference = TString("samplers") + suffix + "[samplerIndex]";
+            ImmutableStringBuilder textureRefBuilder(kTexturesStr.length() + suffix.length() +
+                                                     kSamplerIndexStr.length());
+            textureRefBuilder << kTexturesStr << suffix << kSamplerIndexStr;
+            *textureReference = textureRefBuilder;
+            ImmutableStringBuilder samplerRefBuilder(kSamplersStr.length() + suffix.length() +
+                                                     kSamplerIndexStr.length());
+            samplerRefBuilder << kSamplersStr << suffix << kSamplerIndexStr;
+            *samplerReference = samplerRefBuilder;
         }
         else
         {
-            out << "    const uint textureIndex = samplerIndex - textureIndexOffset" << suffix
-                << ";\n";
-            *textureReference = TString("textures") + suffix + "[textureIndex]";
-            out << "    const uint samplerArrayIndex = samplerIndex - samplerIndexOffset" << suffix
-                << ";\n";
-            *samplerReference = TString("samplers") + suffix + "[samplerArrayIndex]";
+            out << "    const uint textureIndex = samplerIndex - textureIndexOffset"
+                << suffix.data() << ";\n";
+            ImmutableStringBuilder textureRefBuilder(kTexturesStr.length() + suffix.length() +
+                                                     kTextureIndexStr.length());
+            textureRefBuilder << kTexturesStr << suffix << kTextureIndexStr;
+            *textureReference = textureRefBuilder;
+
+            out << "    const uint samplerArrayIndex = samplerIndex - samplerIndexOffset"
+                << suffix.data() << ";\n";
+            ImmutableStringBuilder samplerRefBuilder(kSamplersStr.length() + suffix.length() +
+                                                     kSamplerArrayIndexStr.length());
+            samplerRefBuilder << kSamplersStr << suffix << kSamplerArrayIndexStr;
+            *samplerReference = samplerRefBuilder;
         }
     }
     else
     {
-        *textureReference = "x";
-        *samplerReference = "s";
+        *textureReference = ImmutableString("x");
+        *samplerReference = ImmutableString("s");
     }
 }
 
 void OutputTextureSizeFunctionBody(TInfoSinkBase &out,
                                    const TextureFunctionHLSL::TextureFunction &textureFunction,
-                                   const TString &textureReference,
+                                   const ImmutableString &textureReference,
                                    bool getDimensionsIgnoresBaseLevel)
 {
     if (IsSampler2DMS(textureFunction.sampler))
@@ -565,7 +585,7 @@ void OutputIntegerTextureSampleFunctionComputations(
     TInfoSinkBase &out,
     const TextureFunctionHLSL::TextureFunction &textureFunction,
     const ShShaderOutput outputType,
-    const TString &textureReference,
+    const ImmutableString &textureReference,
     TString *texCoordX,
     TString *texCoordY,
     TString *texCoordZ)
@@ -811,8 +831,8 @@ void OutputTextureSampleFunctionReturnStatement(
     TInfoSinkBase &out,
     const TextureFunctionHLSL::TextureFunction &textureFunction,
     const ShShaderOutput outputType,
-    const TString &textureReference,
-    const TString &samplerReference,
+    const ImmutableString &textureReference,
+    const ImmutableString &samplerReference,
     const TString &texCoordX,
     const TString &texCoordY,
     const TString &texCoordZ)
@@ -1291,8 +1311,8 @@ void TextureFunctionHLSL::textureFunctionHeader(TInfoSinkBase &out,
         // sampling we need to call the function directly on references to the texture and sampler
         // arrays. The bug was found using dEQP-GLES3.functional.shaders.discard*loop_texture*
         // tests.
-        TString textureReference;
-        TString samplerReference;
+        ImmutableString textureReference("");
+        ImmutableString samplerReference("");
         GetTextureReference(out, textureFunction, outputType, &textureReference, &samplerReference);
 
         if (textureFunction.method == TextureFunction::SIZE)

src/compiler/translator/UtilsHLSL.cpp

@@ -218,7 +218,7 @@ HLSLTextureGroup TextureGroup(const TBasicType type, TLayoutImageInternalFormat
     return HLSL_TEXTURE_UNKNOWN;
 }
 
-TString TextureString(const HLSLTextureGroup textureGroup)
+const char *TextureString(const HLSLTextureGroup textureGroup)
 {
     switch (textureGroup)
     {
@@ -277,12 +277,12 @@ TString TextureString(const HLSLTextureGroup textureGroup)
     return "<unknown read texture type>";
 }
 
-TString TextureString(const TBasicType type, TLayoutImageInternalFormat imageInternalFormat)
+const char *TextureString(const TBasicType type, TLayoutImageInternalFormat imageInternalFormat)
 {
     return TextureString(TextureGroup(type, imageInternalFormat));
 }
 
-TString TextureGroupSuffix(const HLSLTextureGroup type)
+const char *TextureGroupSuffix(const HLSLTextureGroup type)
 {
     switch (type)
     {
@@ -341,7 +341,8 @@ TString TextureGroupSuffix(const HLSLTextureGroup type)
     return "<unknown texture type>";
 }
 
-TString TextureGroupSuffix(const TBasicType type, TLayoutImageInternalFormat imageInternalFormat)
+const char *TextureGroupSuffix(const TBasicType type,
+                               TLayoutImageInternalFormat imageInternalFormat)
 {
     return TextureGroupSuffix(TextureGroup(type, imageInternalFormat));
 }

src/compiler/translator/UtilsHLSL.h

@@ -87,12 +87,12 @@ enum HLSLRWTextureGroup
 
 HLSLTextureGroup TextureGroup(const TBasicType type,
                               TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
-TString TextureString(const HLSLTextureGroup textureGroup);
-TString TextureString(const TBasicType type,
-                      TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
-TString TextureGroupSuffix(const HLSLTextureGroup type);
-TString TextureGroupSuffix(const TBasicType type,
-                           TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
+const char *TextureString(const HLSLTextureGroup textureGroup);
+const char *TextureString(const TBasicType type,
+                          TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
+const char *TextureGroupSuffix(const HLSLTextureGroup type);
+const char *TextureGroupSuffix(const TBasicType type,
+                               TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
 TString TextureTypeSuffix(const TBasicType type,
                           TLayoutImageInternalFormat imageInternalFormat = EiifUnspecified);
 HLSLRWTextureGroup RWTextureGroup(const TBasicType type,