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Added compilation failure if a max ubo size is exceeded #164038

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Merged
merged 4 commits into from
Feb 26, 2025
Merged

Added compilation failure if a max ubo size is exceeded #164038

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80e298f
Added compilation failure if a max ubo size is exceeded
gaaclarke Feb 24, 2025
2444654
removed print
gaaclarke Feb 24, 2025
6d4706d
removed unused arg
gaaclarke Feb 24, 2025
6a01241
added comment
gaaclarke Feb 24, 2025
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27 changes: 27 additions & 0 deletions engine/src/flutter/impeller/compiler/compiler.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,11 @@ constexpr const char* kEGLImageExternalExtension300 =
"GL_OES_EGL_image_external_essl3";
} // namespace

// This value should be <= 7372. UBOs can be larger on some devices but a
// performance cost will be paid.
// https://docs.qualcomm.com/bundle/publicresource/topics/80-78185-2/best_practices.html?product=1601111740035277#buffer-best-practices
static const uint32_t kMaxUniformBufferSize = 6208;
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The theory is that this isn't sufficient, but this is the max size right now and it's used by conical_gradient_uniform_fill.frag


static uint32_t ParseMSLVersion(const std::string& msl_version) {
std::stringstream sstream(msl_version);
std::string version_part;
Expand Down Expand Up @@ -257,6 +262,21 @@ static CompilerBackend CreateCompiler(const spirv_cross::ParsedIR& ir,
return compiler;
}

namespace {
uint32_t CalculateUBOSize(const spirv_cross::Compiler* compiler) {
spirv_cross::ShaderResources resources = compiler->get_shader_resources();
uint32_t result = 0;
for (const spirv_cross::Resource& ubo : resources.uniform_buffers) {
const spirv_cross::SPIRType& ubo_type =
compiler->get_type(ubo.base_type_id);
uint32_t size = compiler->get_declared_struct_size(ubo_type);
result += size;
}
return result;
}

} // namespace

Compiler::Compiler(const std::shared_ptr<const fml::Mapping>& source_mapping,
const SourceOptions& source_options,
Reflector::Options reflector_options)
Expand Down Expand Up @@ -410,6 +430,13 @@ Compiler::Compiler(const std::shared_ptr<const fml::Mapping>& source_mapping,
return;
}

uint32_t ubo_size = CalculateUBOSize(sl_compiler.GetCompiler());
if (ubo_size > kMaxUniformBufferSize) {
COMPILER_ERROR(error_stream_) << "Uniform buffer size exceeds max ("
<< kMaxUniformBufferSize << "): " << ubo_size;
return;
}

// We need to invoke the compiler even if we don't use the SL mapping later
// for Vulkan. The reflector needs information that is only valid after a
// successful compilation call.
Expand Down