[HLSL][SPIR-V] Implement vk::ext_builtin_input attribute (#138530)

This variable attribute is used in HLSL to add Vulkan specific builtins
in a shader.
The attribute is documented here:

https://github.com/microsoft/hlsl-specs/blob/17727e88fd1cb09013cb3a144110826af05f4dd5/proposals/0011-inline-spirv.md

Those variable, even if marked as `static` are externally initialized by
the pipeline/driver/GPU. This is handled by moving them to a specific
address space `hlsl_input`, also added by this commit.

The design for input variables in Clang can be found here:
https://github.com/llvm/wg-hlsl/blob/355771361ef69259fef39a65caef8bff9cb4046d/proposals/0019-spirv-input-builtin.md


Co-authored-by: Justin Bogner <mail@justinbogner.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets/AMDGPU.cpp b/clang/lib/Basic/Targets/AMDGPU.cpp
index 9a595c5..8d5489b 100644
--- a/clang/lib/Basic/Targets/AMDGPU.cpp
+++ b/clang/lib/Basic/Targets/AMDGPU.cpp
@@ -62,6 +62,7 @@ const LangASMap AMDGPUTargetInfo::AMDGPUDefIsGenMap = {
     // will break loudly.
     llvm::AMDGPUAS::PRIVATE_ADDRESS, // hlsl_private
     llvm::AMDGPUAS::GLOBAL_ADDRESS,  // hlsl_device
+    llvm::AMDGPUAS::PRIVATE_ADDRESS, // hlsl_input
 };
 
 const LangASMap AMDGPUTargetInfo::AMDGPUDefIsPrivMap = {
@@ -89,6 +90,7 @@ const LangASMap AMDGPUTargetInfo::AMDGPUDefIsPrivMap = {
     llvm::AMDGPUAS::CONSTANT_ADDRESS, // hlsl_constant
     llvm::AMDGPUAS::PRIVATE_ADDRESS,  // hlsl_private
     llvm::AMDGPUAS::GLOBAL_ADDRESS,   // hlsl_device
+    llvm::AMDGPUAS::PRIVATE_ADDRESS,  // hlsl_input
 };
 } // namespace targets
 } // namespace clang