[Refactor] (ShaderTranspiler, DirectVulkan): replace the hand-rolled SPIR-V word walkers with a DecoratePositionInvariantPass and SPIRV-Reflect-based InstanceIndex detection

This commit is contained in:
2026-07-20 08:35:00 -04:00
parent c81dd04f08
commit 65ea54da9e
10 changed files with 543 additions and 111 deletions
@@ -0,0 +1,25 @@
cmake_minimum_required(VERSION 3.14)
add_executable(
SpirvPassTest
SpirvPassTest.cpp
)
target_include_directories(SpirvPassTest PRIVATE
${MGL_ROOT}/include
${MGL_ROOT}/MobileGL
${MGL_ROOT}/3rdparty/SPIRV-Reflect
)
target_link_libraries(
SpirvPassTest PRIVATE
GTest::gtest_main
${LINK_LIBRARIES}
)
if (MSVC)
target_compile_options(SpirvPassTest PRIVATE /Zc:preprocessor)
endif()
include(GoogleTest)
gtest_discover_tests(SpirvPassTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)
@@ -0,0 +1,170 @@
// MobileGL - MobileGL/MG_Test/ShaderTranspiler/SpirvPassTest.cpp
// Copyright (c) 2025-2026 MobileGL-Dev
// Licensed under the GNU Lesser General Public License v3.0:
// https://www.gnu.org/licenses/gpl-3.0.txt
// https://www.gnu.org/licenses/lgpl-3.0.txt
// SPDX-License-Identifier: LGPL-3.0-only
// End of Source File Header
#include <gtest/gtest.h>
#include <MG_Util/ShaderTranspiler/ShaderCompiler.h>
#include <spirv_reflect.h>
using namespace MobileGL;
using MobileGL::MG_Util::ShaderTranspiler::ShaderCompiler;
namespace {
// glslangValidator -V output. Both are vertex shaders writing gl_Position through
// the gl_PerVertex block, i.e. the Position builtin arrives as OpMemberDecorate rather
// than a plain OpDecorate - the shape real glslang output actually takes.
// #version 450
// layout(location = 0) in vec4 inPos;
// void main() { gl_Position = inPos; }
constexpr Uint32 kPlainVertexSpirv[] = {
0x07230203u, 0x00010000u, 0x0008000bu, 0x00000015u, 0x00000000u, 0x00020011u,
0x00000001u, 0x0006000bu, 0x00000001u, 0x4c534c47u, 0x6474732eu, 0x3035342eu,
0x00000000u, 0x0003000eu, 0x00000000u, 0x00000001u, 0x0007000fu, 0x00000000u,
0x00000004u, 0x6e69616du, 0x00000000u, 0x0000000du, 0x00000011u, 0x00030003u,
0x00000002u, 0x000001c2u, 0x00040005u, 0x00000004u, 0x6e69616du, 0x00000000u,
0x00060005u, 0x0000000bu, 0x505f6c67u, 0x65567265u, 0x78657472u, 0x00000000u,
0x00060006u, 0x0000000bu, 0x00000000u, 0x505f6c67u, 0x7469736fu, 0x006e6f69u,
0x00070006u, 0x0000000bu, 0x00000001u, 0x505f6c67u, 0x746e696fu, 0x657a6953u,
0x00000000u, 0x00070006u, 0x0000000bu, 0x00000002u, 0x435f6c67u, 0x4470696cu,
0x61747369u, 0x0065636eu, 0x00070006u, 0x0000000bu, 0x00000003u, 0x435f6c67u,
0x446c6c75u, 0x61747369u, 0x0065636eu, 0x00030005u, 0x0000000du, 0x00000000u,
0x00040005u, 0x00000011u, 0x6f506e69u, 0x00000073u, 0x00030047u, 0x0000000bu,
0x00000002u, 0x00050048u, 0x0000000bu, 0x00000000u, 0x0000000bu, 0x00000000u,
0x00050048u, 0x0000000bu, 0x00000001u, 0x0000000bu, 0x00000001u, 0x00050048u,
0x0000000bu, 0x00000002u, 0x0000000bu, 0x00000003u, 0x00050048u, 0x0000000bu,
0x00000003u, 0x0000000bu, 0x00000004u, 0x00040047u, 0x00000011u, 0x0000001eu,
0x00000000u, 0x00020013u, 0x00000002u, 0x00030021u, 0x00000003u, 0x00000002u,
0x00030016u, 0x00000006u, 0x00000020u, 0x00040017u, 0x00000007u, 0x00000006u,
0x00000004u, 0x00040015u, 0x00000008u, 0x00000020u, 0x00000000u, 0x0004002bu,
0x00000008u, 0x00000009u, 0x00000001u, 0x0004001cu, 0x0000000au, 0x00000006u,
0x00000009u, 0x0006001eu, 0x0000000bu, 0x00000007u, 0x00000006u, 0x0000000au,
0x0000000au, 0x00040020u, 0x0000000cu, 0x00000003u, 0x0000000bu, 0x0004003bu,
0x0000000cu, 0x0000000du, 0x00000003u, 0x00040015u, 0x0000000eu, 0x00000020u,
0x00000001u, 0x0004002bu, 0x0000000eu, 0x0000000fu, 0x00000000u, 0x00040020u,
0x00000010u, 0x00000001u, 0x00000007u, 0x0004003bu, 0x00000010u, 0x00000011u,
0x00000001u, 0x00040020u, 0x00000013u, 0x00000003u, 0x00000007u, 0x00050036u,
0x00000002u, 0x00000004u, 0x00000000u, 0x00000003u, 0x000200f8u, 0x00000005u,
0x0004003du, 0x00000007u, 0x00000012u, 0x00000011u, 0x00050041u, 0x00000013u,
0x00000014u, 0x0000000du, 0x0000000fu, 0x0003003eu, 0x00000014u, 0x00000012u,
0x000100fdu, 0x00010038u,
};
// ... plus `invariant gl_Position;` - already carries OpMemberDecorate %gl_PerVertex 0
// Invariant, so the pass must not add a duplicate.
constexpr Uint32 kAlreadyInvariantVertexSpirv[] = {
0x07230203u, 0x00010000u, 0x0008000bu, 0x00000015u, 0x00000000u, 0x00020011u,
0x00000001u, 0x0006000bu, 0x00000001u, 0x4c534c47u, 0x6474732eu, 0x3035342eu,
0x00000000u, 0x0003000eu, 0x00000000u, 0x00000001u, 0x0007000fu, 0x00000000u,
0x00000004u, 0x6e69616du, 0x00000000u, 0x0000000du, 0x00000011u, 0x00030003u,
0x00000002u, 0x000001c2u, 0x00040005u, 0x00000004u, 0x6e69616du, 0x00000000u,
0x00060005u, 0x0000000bu, 0x505f6c67u, 0x65567265u, 0x78657472u, 0x00000000u,
0x00060006u, 0x0000000bu, 0x00000000u, 0x505f6c67u, 0x7469736fu, 0x006e6f69u,
0x00070006u, 0x0000000bu, 0x00000001u, 0x505f6c67u, 0x746e696fu, 0x657a6953u,
0x00000000u, 0x00070006u, 0x0000000bu, 0x00000002u, 0x435f6c67u, 0x4470696cu,
0x61747369u, 0x0065636eu, 0x00070006u, 0x0000000bu, 0x00000003u, 0x435f6c67u,
0x446c6c75u, 0x61747369u, 0x0065636eu, 0x00030005u, 0x0000000du, 0x00000000u,
0x00040005u, 0x00000011u, 0x6f506e69u, 0x00000073u, 0x00030047u, 0x0000000bu,
0x00000002u, 0x00050048u, 0x0000000bu, 0x00000000u, 0x0000000bu, 0x00000000u,
0x00040048u, 0x0000000bu, 0x00000000u, 0x00000012u, 0x00050048u, 0x0000000bu,
0x00000001u, 0x0000000bu, 0x00000001u, 0x00050048u, 0x0000000bu, 0x00000002u,
0x0000000bu, 0x00000003u, 0x00050048u, 0x0000000bu, 0x00000003u, 0x0000000bu,
0x00000004u, 0x00040047u, 0x00000011u, 0x0000001eu, 0x00000000u, 0x00020013u,
0x00000002u, 0x00030021u, 0x00000003u, 0x00000002u, 0x00030016u, 0x00000006u,
0x00000020u, 0x00040017u, 0x00000007u, 0x00000006u, 0x00000004u, 0x00040015u,
0x00000008u, 0x00000020u, 0x00000000u, 0x0004002bu, 0x00000008u, 0x00000009u,
0x00000001u, 0x0004001cu, 0x0000000au, 0x00000006u, 0x00000009u, 0x0006001eu,
0x0000000bu, 0x00000007u, 0x00000006u, 0x0000000au, 0x0000000au, 0x00040020u,
0x0000000cu, 0x00000003u, 0x0000000bu, 0x0004003bu, 0x0000000cu, 0x0000000du,
0x00000003u, 0x00040015u, 0x0000000eu, 0x00000020u, 0x00000001u, 0x0004002bu,
0x0000000eu, 0x0000000fu, 0x00000000u, 0x00040020u, 0x00000010u, 0x00000001u,
0x00000007u, 0x0004003bu, 0x00000010u, 0x00000011u, 0x00000001u, 0x00040020u,
0x00000013u, 0x00000003u, 0x00000007u, 0x00050036u, 0x00000002u, 0x00000004u,
0x00000000u, 0x00000003u, 0x000200f8u, 0x00000005u, 0x0004003du, 0x00000007u,
0x00000012u, 0x00000011u, 0x00050041u, 0x00000013u, 0x00000014u, 0x0000000du,
0x0000000fu, 0x0003003eu, 0x00000014u, 0x00000012u, 0x000100fdu, 0x00010038u,
};
// OpMemberDecorate <struct-id> <member> <decoration>
constexpr Uint32 kOpMemberDecorate = 72;
constexpr Uint32 kDecorationInvariant = 18;
constexpr Uint32 kSpirvHeaderWordCount = 5;
// Test-side reference walker. Deliberately independent of the production code so a bug in
// the pass cannot hide behind the same helper; only used to count what the pass emitted.
Uint32 CountInvariantMemberDecorations(const Vector<Uint32>& spirv) {
Uint32 count = 0;
for (SizeT i = kSpirvHeaderWordCount; i < spirv.size();) {
const Uint32 wordCount = spirv[i] >> 16;
const Uint32 opcode = spirv[i] & 0xFFFFu;
if (wordCount == 0 || i + wordCount > spirv.size()) {
break;
}
if (opcode == kOpMemberDecorate && wordCount >= 4 && spirv[i + 3] == kDecorationInvariant) {
++count;
}
i += wordCount;
}
return count;
}
template <SizeT WordCount>
Vector<Uint32> ToVector(const Uint32 (&words)[WordCount]) {
return Vector<Uint32>(words, words + WordCount);
}
} // namespace
// --- DecoratePositionInvariantPass ---
TEST(DecoratePositionInvariant, AddsInvariantToThePositionMember) {
const Vector<Uint32> input = ToVector(kPlainVertexSpirv);
ASSERT_EQ(CountInvariantMemberDecorations(input), 0u);
Vector<Uint32> output;
ASSERT_TRUE(ShaderCompiler::DecoratePositionInvariantForVulkan(input, output));
EXPECT_EQ(CountInvariantMemberDecorations(output), 1u);
}
TEST(DecoratePositionInvariant, DoesNotDuplicateAnExistingInvariant) {
const Vector<Uint32> input = ToVector(kAlreadyInvariantVertexSpirv);
ASSERT_EQ(CountInvariantMemberDecorations(input), 1u);
Vector<Uint32> output;
ASSERT_TRUE(ShaderCompiler::DecoratePositionInvariantForVulkan(input, output));
EXPECT_EQ(CountInvariantMemberDecorations(output), 1u);
// The pass reports SuccessWithoutChange here, and SPIRV-Tools asserts (in assert-enabled
// builds) that such a run round-trips byte-identically. Pin that from the outside so an
// assert-enabled CI build cannot be the first thing to discover a violation.
EXPECT_EQ(output, input);
}
TEST(DecoratePositionInvariant, IsIdempotent) {
Vector<Uint32> once;
ASSERT_TRUE(ShaderCompiler::DecoratePositionInvariantForVulkan(ToVector(kPlainVertexSpirv), once));
Vector<Uint32> twice;
ASSERT_TRUE(ShaderCompiler::DecoratePositionInvariantForVulkan(once, twice));
EXPECT_EQ(CountInvariantMemberDecorations(twice), 1u);
}
TEST(DecoratePositionInvariant, OutputStaysAReflectableModule) {
Vector<Uint32> output;
ASSERT_TRUE(ShaderCompiler::DecoratePositionInvariantForVulkan(ToVector(kPlainVertexSpirv), output));
SpvReflectShaderModule module{};
ASSERT_EQ(spvReflectCreateShaderModule(output.size() * sizeof(Uint32), output.data(), &module),
SPV_REFLECT_RESULT_SUCCESS);
EXPECT_EQ(module.entry_point_count, 1u);
spvReflectDestroyShaderModule(&module);
}
TEST(DecoratePositionInvariant, RejectsGarbageInput) {
const Vector<Uint32> notSpirv{0xdeadbeefu, 0u, 0u, 0u, 0u};
Vector<Uint32> output;
EXPECT_FALSE(ShaderCompiler::DecoratePositionInvariantForVulkan(notSpirv, output));
}