[SPIR-V] Fix OpName and LinkageAttributes decoration of global variables (llvm#120492)

This PR changes `getGlobalIdentifier()` into `getName()` value when
creating a name of a global variable, and fixes generation of
LinkageAttributes decoration of global variables by taking into account
Private Linkage in addition to Internal.

Previous implementation led to an issue with back translation of SPIR-V
to LLVM IR, e.g.:

```
@__const.G1 = private unnamed_addr addrspace(1) constant %my_type undef
...
Fails to verify module: 'common' global may not be marked constant!
ptr addrspace(1) @"llvm-link;__const.G1"
```

A reproducer is included as a new test case.

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVEmitIntrinsics.cpp

@@ -1841,20 +1841,20 @@ void SPIRVEmitIntrinsics::processGlobalValue(GlobalVariable &GV,
   // Skip special artifical variable llvm.global.annotations.
   if (GV.getName() == "llvm.global.annotations")
     return;
-  if (GV.hasInitializer() && !isa<UndefValue>(GV.getInitializer())) {
+  Constant *Init = nullptr;
+  if (hasInitializer(&GV)) {
     // Deduce element type and store results in Global Registry.
     // Result is ignored, because TypedPointerType is not supported
     // by llvm IR general logic.
     deduceElementTypeHelper(&GV, false);
-    Constant *Init = GV.getInitializer();
+    Init = GV.getInitializer();
     Type *Ty = isAggrConstForceInt32(Init) ? B.getInt32Ty() : Init->getType();
     Constant *Const = isAggrConstForceInt32(Init) ? B.getInt32(1) : Init;
     auto *InitInst = B.CreateIntrinsic(Intrinsic::spv_init_global,
                                        {GV.getType(), Ty}, {&GV, Const});
     InitInst->setArgOperand(1, Init);
   }
-  if ((!GV.hasInitializer() || isa<UndefValue>(GV.getInitializer())) &&
-      GV.getNumUses() == 0)
+  if (!Init && GV.getNumUses() == 0)
     B.CreateIntrinsic(Intrinsic::spv_unref_global, GV.getType(), &GV);
 }
 

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -3478,7 +3478,7 @@ bool SPIRVInstructionSelector::selectGlobalValue(
       ID = UnnamedGlobalIDs.size();
     GlobalIdent = "__unnamed_" + Twine(ID).str();
   } else {
-    GlobalIdent = GV->getGlobalIdentifier();
+    GlobalIdent = GV->getName();
   }
 
   // Behaviour of functions as operands depends on availability of the
@@ -3541,18 +3541,16 @@ bool SPIRVInstructionSelector::selectGlobalValue(
   auto GlobalVar = cast<GlobalVariable>(GV);
   assert(GlobalVar->getName() != "llvm.global.annotations");
 
-  bool HasInit = GlobalVar->hasInitializer() &&
-                 !isa<UndefValue>(GlobalVar->getInitializer());
-  // Skip empty declaration for GVs with initilaizers till we get the decl with
+  // Skip empty declaration for GVs with initializers till we get the decl with
   // passed initializer.
-  if (HasInit && !Init)
+  if (hasInitializer(GlobalVar) && !Init)
     return true;
 
-  bool HasLnkTy = GV->getLinkage() != GlobalValue::InternalLinkage;
+  bool HasLnkTy = !GV->hasInternalLinkage() && !GV->hasPrivateLinkage();
   SPIRV::LinkageType::LinkageType LnkType =
-      (GV->isDeclaration() || GV->hasAvailableExternallyLinkage())
+      GV->isDeclarationForLinker()
           ? SPIRV::LinkageType::Import
-          : (GV->getLinkage() == GlobalValue::LinkOnceODRLinkage &&
+          : (GV->hasLinkOnceODRLinkage() &&
                      STI.canUseExtension(SPIRV::Extension::SPV_KHR_linkonce_odr)
                  ? SPIRV::LinkageType::LinkOnceODR
                  : SPIRV::LinkageType::Export);

llvm/lib/Target/SPIRV/SPIRVUtils.h

@@ -17,6 +17,7 @@
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/IR/Dominators.h"
+#include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/TypedPointerType.h"
 #include <queue>
@@ -236,6 +237,10 @@ Type *parseBasicTypeName(StringRef &TypeName, LLVMContext &Ctx);
 // Returns true if the function was changed.
 bool sortBlocks(Function &F);
 
+inline bool hasInitializer(const GlobalVariable *GV) {
+  return GV->hasInitializer() && !isa<UndefValue>(GV->getInitializer());
+}
+
 // True if this is an instance of TypedPointerType.
 inline bool isTypedPointerTy(const Type *T) {
   return T && T->getTypeID() == Type::TypedPointerTyID;

llvm/test/CodeGen/SPIRV/global-var-name-linkage.ll

@@ -0,0 +1,59 @@
+; Check names and decoration of global variables.
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: OpName %[[#id18:]] "G1"
+; CHECK-DAG: OpName %[[#id22:]] "g1"
+; CHECK-DAG: OpName %[[#id23:]] "g2"
+; CHECK-DAG: OpName %[[#id27:]] "g4"
+; CHECK-DAG: OpName %[[#id30:]] "c1"
+; CHECK-DAG: OpName %[[#id31:]] "n_t"
+; CHECK-DAG: OpName %[[#id32:]] "w"
+; CHECK-DAG: OpName %[[#id34:]] "a.b"
+; CHECK-DAG: OpName %[[#id35:]] "e"
+; CHECK-DAG: OpName %[[#id36:]] "y.z"
+; CHECK-DAG: OpName %[[#id38:]] "x"
+
+; CHECK-NOT: OpDecorate %[[#id18]] LinkageAttributes
+; CHECK-DAG: OpDecorate %[[#id18]] Constant
+; CHECK-DAG: OpDecorate %[[#id22]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id22]] LinkageAttributes "g1" Export
+; CHECK-DAG: OpDecorate %[[#id23]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id27]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id27]] LinkageAttributes "g4" Export
+; CHECK-DAG: OpDecorate %[[#id30]] Constant
+; CHECK-DAG: OpDecorate %[[#id30]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id30]] LinkageAttributes "c1" Export
+; CHECK-DAG: OpDecorate %[[#id31]] Constant
+; CHECK-DAG: OpDecorate %[[#id31]] LinkageAttributes "n_t" Import
+; CHECK-DAG: OpDecorate %[[#id32]] Constant
+; CHECK-DAG: OpDecorate %[[#id32]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id32]] LinkageAttributes "w" Export
+; CHECK-DAG: OpDecorate %[[#id34]] Constant
+; CHECK-DAG: OpDecorate %[[#id34]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id35]] LinkageAttributes "e" Import
+; CHECK-DAG: OpDecorate %[[#id36]] Alignment 4
+; CHECK-DAG: OpDecorate %[[#id38]] Constant
+; CHECK-DAG: OpDecorate %[[#id38]] Alignment 4
+
+%"class.sycl::_V1::nd_item" = type { i8 }
+
+@G1 = private unnamed_addr addrspace(1) constant %"class.sycl::_V1::nd_item" poison, align 1
+@g1 = addrspace(1) global i32 1, align 4
+@g2 = internal addrspace(1) global i32 2, align 4
+@g4 = common addrspace(1) global i32 0, align 4
+@c1 = addrspace(2) constant [2 x i32] [i32 0, i32 1], align 4
+@n_t = external addrspace(2) constant [256 x i32]
+@w = addrspace(1) constant i32 0, align 4
+@a.b = internal addrspace(2) constant [2 x i32] [i32 2, i32 3], align 4
+@e = external addrspace(1) global i32
+@y.z = internal addrspace(1) global i32 0, align 4
+@x = internal addrspace(2) constant float 1.000000e+00, align 4
+
+define internal spir_func void @foo(ptr addrspace(4) align 1 %arg) {
+  ret void
+}