[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.

Author: Keenuts

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);
 

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;

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 %}
+
+@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}