[llvm] [SPIR-V] Fix LinkageAttribute emission for Vulkan (PR #143902)

[Nathan Gauër via llvm-commits]

https://github.com/Keenuts created https://github.com/llvm/llvm-project/pull/143902

Linkage capability is required for LinkageAttribute. This capability could be allowed in Shaders, but the Vulkan environment do not support it so we should not emit this decoration under Vulkan.

This requires #143888 to work.

>From e3429c5133290e45221e76efe76e7293cb73d118 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nathan=20Gau=C3=ABr?= <brioche at google.com>
Date: Thu, 12 Jun 2025 15:40:25 +0200
Subject: [PATCH] [SPIR-V] Fix LinkageAttribute emission for Vulkan

Linkage capability is required for LinkageAttribute. This capability
could be allowed in Shaders, but the Vulkan environment do not support
it so we should not emit this decoration under Vulkan.
---
 llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp |  4 +++-
 llvm/lib/Target/SPIRV/SPIRVSubtarget.h        |  1 +
 .../SPIRV/linkage/link-attribute-vk.ll        | 23 +++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/SPIRV/linkage/link-attribute-vk.ll

diff --git a/llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp b/llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp
index c5e8269efd25a..25b4ce9658049 100644
--- a/llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVGlobalRegistry.cpp
@@ -780,7 +780,9 @@ Register SPIRVGlobalRegistry::buildGlobalVariable(
     buildOpDecorate(Reg, MIRBuilder, SPIRV::Decoration::Alignment, {Alignment});
   }
 
-  if (HasLinkageTy)
+  // LinkageAttributes required Linkage capability. This capability is not
+  // supported by Vulkan.
+  if (HasLinkageTy && !ST.isVulkan())
     buildOpDecorate(Reg, MIRBuilder, SPIRV::Decoration::LinkageAttributes,
                     {static_cast<uint32_t>(LinkageType)}, Name);
 
diff --git a/llvm/lib/Target/SPIRV/SPIRVSubtarget.h b/llvm/lib/Target/SPIRV/SPIRVSubtarget.h
index ad3e38d296ed7..008a66cb356bf 100644
--- a/llvm/lib/Target/SPIRV/SPIRVSubtarget.h
+++ b/llvm/lib/Target/SPIRV/SPIRVSubtarget.h
@@ -101,6 +101,7 @@ class SPIRVSubtarget : public SPIRVGenSubtargetInfo {
     return TargetTriple.getArch() == Triple::spirv32 ||
            TargetTriple.getArch() == Triple::spirv64;
   }
+  bool isVulkan() const { return TargetTriple.getOS() == Triple::Vulkan; }
   const std::string &getTargetTripleAsStr() const { return TargetTriple.str(); }
   VersionTuple getSPIRVVersion() const { return SPIRVVersion; };
   bool isAtLeastSPIRVVer(VersionTuple VerToCompareTo) const;
diff --git a/llvm/test/CodeGen/SPIRV/linkage/link-attribute-vk.ll b/llvm/test/CodeGen/SPIRV/linkage/link-attribute-vk.ll
new file mode 100644
index 0000000000000..95a636e16611c
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/linkage/link-attribute-vk.ll
@@ -0,0 +1,23 @@
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan1.3-pixel %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan1.3-pixel %s -o - -filetype=obj | spirv-val --target-env vulkan1.3 %}
+
+ at sv_position = external thread_local local_unnamed_addr addrspace(7) externally_initialized constant <4 x float>, !spirv.Decorations !0
+
+; CHECK-NOT: OpDecorate %[[#var]] LinkageAttributes "sv_position" Import
+
+; CHECK-DAG: %[[#float:]] = OpTypeFloat 32
+; CHECK-DAG: %[[#float4:]] = OpTypeVector %[[#float]]
+; CHECK-DAG: %[[#type:]] = OpTypePointer Input %[[#float4]]
+; CHECK-DAG: %[[#var:]] = OpVariable %[[#type]] Input
+
+; CHECK-NOT: OpDecorate %[[#var]] LinkageAttributes "sv_position" Import
+
+define void @main() #1 {
+entry:
+  ret void
+}
+
+attributes #1 = { "hlsl.shader"="pixel" }
+
+!0 = !{!1}
+!1 = !{i32 11, i32 0}