0008-Add-GLSL-variable-byte-size-limits-to-ShBuiltInResou.patch

From a5f0aab16397f6e46f4b5c50e35347ce678cfbb0 Mon Sep 17 00:00:00 2001

From: Kelsey Gilbert <kelsey.gilbert@mozilla.com>

Date: Tue, 4 Jun 2024 15:37:29 -0700

Subject: [PATCH] Add GLSL variable byte size limits to ShBuiltInResources.

---

 include/GLSLANG/ShaderLang.h             |  5 +++++

 src/compiler/translator/Compiler.cpp     |  3 +++

 src/compiler/translator/ParseContext.cpp | 20 +++++++-------------

 src/compiler/translator/ShaderLang.cpp   |  6 ++++++

 4 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/include/GLSLANG/ShaderLang.h b/include/GLSLANG/ShaderLang.h

index 200eaac2c5..135daac147 100644

--- a/include/GLSLANG/ShaderLang.h

+++ b/include/GLSLANG/ShaderLang.h

@@ -764,6 +764,11 @@ struct ShBuiltInResources

     // ANGLE_shader_pixel_local_storage.

     int MaxPixelLocalStoragePlanes;

     int MaxCombinedDrawBuffersAndPixelLocalStoragePlanes;

+    // Variable size limits for webgl-mode validation.

+    size_t MaxVariableSizeInBytes;

+    size_t MaxPrivateVariableSizeInBytes;

+    size_t MaxTotalPrivateVariableSizeInBytes;

};

//

diff --git a/src/compiler/translator/Compiler.cpp b/src/compiler/translator/Compiler.cpp

index 9ba125a178..ebf0bd49c6 100644

--- a/src/compiler/translator/Compiler.cpp

+++ b/src/compiler/translator/Compiler.cpp

@@ -1511,6 +1511,9 @@ void TCompiler::setResourceString()

         << ":MaxFragmentImageUniforms:" << mResources.MaxFragmentImageUniforms

         << ":MaxComputeImageUniforms:" << mResources.MaxComputeImageUniforms

         << ":MaxCombinedImageUniforms:" << mResources.MaxCombinedImageUniforms

+        << ":MaxVariableSizeInBytes:" << mResources.MaxVariableSizeInBytes

+        << ":MaxPrivateVariableSizeInBytes:" << mResources.MaxPrivateVariableSizeInBytes

+        << ":MaxTotalPrivateVariableSizeInBytes:" << mResources.MaxTotalPrivateVariableSizeInBytes

         << ":MaxCombinedShaderOutputResources:" << mResources.MaxCombinedShaderOutputResources

         << ":MaxComputeWorkGroupCountX:" << mResources.MaxComputeWorkGroupCount[0]

         << ":MaxComputeWorkGroupCountY:" << mResources.MaxComputeWorkGroupCount[1]

diff --git a/src/compiler/translator/ParseContext.cpp b/src/compiler/translator/ParseContext.cpp

index 9852c0c9cd..efd6e436ac 100644

--- a/src/compiler/translator/ParseContext.cpp

+++ b/src/compiler/translator/ParseContext.cpp

@@ -45,15 +45,6 @@ namespace

 const int kWebGLMaxStructNesting = 4;

-// Arbitrarily enforce that all types declared with a size in bytes of over 2 GB will cause

-// compilation failure.

-//

-// For local and global variables, the limit is much lower (64KB) as that much memory won't fit in

-// the GPU registers anyway.

-constexpr size_t kWebGLMaxVariableSizeInBytes        = static_cast<size_t>(2) * 1024 * 1024 * 1024;

-constexpr size_t kWebGLMaxPrivateVariableSizeInBytes = static_cast<size_t>(64) * 1024;

-constexpr size_t kWebGLMaxTotalPrivateVariableSizeInBytes = static_cast<size_t>(16) * 1024 * 1024;

 // The 1024 character identifier limit, `-2` for the `_u`

 constexpr size_t kMaxAvailableIdentifierLength = 1022;

@@ -1755,7 +1746,8 @@ bool TParseContext::checkVariableSize(const TSourceLoc &line,

     const size_t variableSize =

         CalculateVariableSize(type, type->isInterfaceBlock() || type->getQualifier() == EvqUniform)

             .ValueOrDefault(std::numeric_limits<size_t>::max());

-    if (variableSize > kWebGLMaxVariableSizeInBytes)

+    if (mResources.MaxVariableSizeInBytes &&

+        variableSize > mResources.MaxVariableSizeInBytes)

         error(line, "Size of declared variable exceeds implementation-defined limit", identifier);

         return false;

@@ -1799,7 +1791,8 @@ bool TParseContext::checkVariableSize(const TSourceLoc &line,

         case EvqPerVertexIn:

         case EvqPerVertexOut:

-            if (variableSize > kWebGLMaxPrivateVariableSizeInBytes)

+            if (mResources.MaxPrivateVariableSizeInBytes &&

+                variableSize > mResources.MaxPrivateVariableSizeInBytes)

                 error(line,

                       "Size of declared private variable exceeds implementation-defined limit",

@@ -10401,8 +10394,9 @@ bool TParseContext::postParseChecks()

     if (mCompileOptions.rejectWebglShadersWithLargeVariables)

-        if (mTotalPrivateVariablesSize.ValueOrDefault(std::numeric_limits<size_t>::max()) >

-            kWebGLMaxTotalPrivateVariableSizeInBytes)

+        if (mResources.MaxTotalPrivateVariableSizeInBytes &&

+            mTotalPrivateVariablesSize.ValueOrDefault(std::numeric_limits<size_t>::max()) >

+                mResources.MaxTotalPrivateVariableSizeInBytes)

             error(TSourceLoc{},

                   "Total size of declared private variables exceeds implementation-defined limit",

diff --git a/src/compiler/translator/ShaderLang.cpp b/src/compiler/translator/ShaderLang.cpp

index 6477eef68e..ebcb1c050e 100644

--- a/src/compiler/translator/ShaderLang.cpp

+++ b/src/compiler/translator/ShaderLang.cpp

@@ -363,6 +363,12 @@ void InitBuiltInResources(ShBuiltInResources *resources)

     resources->MaxTessEvaluationUniformBlocks        = 12;

     resources->MaxSamples = 4;

+    // Prevent unrealistically large WebGL variable sizes. These defaults match the current parser

+    // limits while allowing embedders to override them.

+    resources->MaxVariableSizeInBytes             = static_cast<size_t>(2) * 1024 * 1024 * 1024;

+    resources->MaxPrivateVariableSizeInBytes      = static_cast<size_t>(64) * 1024;

+    resources->MaxTotalPrivateVariableSizeInBytes = static_cast<size_t>(16) * 1024 * 1024;

//

--

2.54.0