[SPIR-V] Crash on assertion when compiling shaders containing SubpassInputs and global struct instances with resource only members

[Dredhog]

Title

Crash on assertion when compiling shaders containing SubpassInputs and global struct instances with resource only members

Functional impact

Compiler crashes. Can't use SubpassInputs and sampler2D types emulated via custom structs and functions in the same shader.

Minimal repro steps

1. Compile the following pixel shader with dxc.exe -T ps_6_0 -E frag -spirv repro_shader.hlsl

struct sampler2D {Texture2D t; SamplerState s;};
//float4 tex2D (sampler2D x, float2 v) {return x.t.Sample(x.s, v);}

sampler2D emulatedSampler2D;

[[vk::input_attachment_index (0)]] SubpassInput<min16float4> MySubpassInput;

float4 frag () : SV_TARGET
{
	return float4(1, 1, 1, 1);
}

Expected result

Shader compiles successfully

Actual result

Compiler crashes at Tools\clang\lib\SPIRV\DeclResultIdMapper.cpp:72: assert(hlsl::IsHLSLResourceType(type) || isResourceOnlyStructure(type));
Crash stack when debugging the compilation with Visual Studio:

>	dxcompiler.dll!llvm_assert(const char * _Message, const char * _File, unsigned int _Line, const char * _Function) Line 23	C++
 	dxcompiler.dll!clang::spirv::`anonymous namespace'::getNumBindingsUsedByResourceType(clang::QualType type) Line 72	C++
 	dxcompiler.dll!clang::spirv::DeclResultIdMapper::decorateResourceBindings() Line 1824	C++
 	dxcompiler.dll!clang::spirv::SpirvEmitter::HandleTranslationUnit(clang::ASTContext & context) Line 571	C++
 	dxcompiler.dll!clang::ParseAST(clang::Sema & S, bool PrintStats, bool SkipFunctionBodies) Line 162	C++
 	dxcompiler.dll!clang::ASTFrontendAction::ExecuteAction() Line 556	C++
 	dxcompiler.dll!clang::FrontendAction::Execute() Line 468	C++
 	dxcompiler.dll!DxcCompiler::Compile(const DxcBuffer * pSource, const wchar_t * * pArguments, unsigned int argCount, IDxcIncludeHandler * pIncludeHandler, const _GUID & riid, void * * ppResult) Line 777	C++
 	dxcompiler.dll!hlsl::DxcCompilerAdapter::WrapCompile(int bPreprocess, IDxcBlob * pSource, const wchar_t * pSourceName, const wchar_t * pEntryPoint, const wchar_t * pTargetProfile, const wchar_t * * pArguments, unsigned int argCount, const DxcDefine * pDefines, unsigned int defineCount, IDxcIncludeHandler * pIncludeHandler, IDxcOperationResult * * ppResult, wchar_t * * ppDebugBlobName, IDxcBlob * * ppDebugBlob) Line 1418	C++
 	dxcompiler.dll!hlsl::DxcCompilerAdapter::CompileWithDebug(IDxcBlob * pSource, const wchar_t * pSourceName, const wchar_t * pEntryPoint, const wchar_t * pTargetProfile, const wchar_t * * pArguments, unsigned int argCount, const DxcDefine * pDefines, unsigned int defineCount, IDxcIncludeHandler * pIncludeHandler, IDxcOperationResult * * ppResult, wchar_t * * ppDebugBlobName, IDxcBlob * * ppDebugBlob) Line 1332	C++
 	dxcompiler.dll!hlsl::DxcCompilerAdapter::Compile(IDxcBlob * pSource, const wchar_t * pSourceName, const wchar_t * pEntryPoint, const wchar_t * pTargetProfile, const wchar_t * * pArguments, unsigned int argCount, const DxcDefine * pDefines, unsigned int defineCount, IDxcIncludeHandler * pIncludeHandler, IDxcOperationResult * * ppResult) Line 72	C++
 	dxc.exe!DxcContext::Compile() Line 868	C++
 	dxc.exe!dxc::main(int argc, const wchar_t * * argv_) Line 1323	C++
 	dxc.exe!wmain(int argc, const wchar_t * * argv_) Line 22	C++
 	dxc.exe!invoke_main() Line 91	C++
 	dxc.exe!__scrt_common_main_seh() Line 288	C++
 	dxc.exe!__scrt_common_main() Line 331	C++
 	dxc.exe!wmainCRTStartup() Line 17	C++
 	kernel32.dll!00007fffca727974()	Unknown

Further technical details

The issue will not reproduce if either the SubpassInput or the sampler2D declaration line is removed. Most likely related to #2695. DXC built from 530958e

[ehsannas]

Thanks for reporting @Dredhog.

[ehsannas]

Sorry for the delay. I'll look into this soon.