Handle translation of DIArgList with single argument (#1385)

If there are more than one argument in DIArgList, we can't represent it in
SPIR-V with the current SPIR-V debug info spec. In this case we drop DIArgList
and DIExpression.

Signed-off-by: Alexey Sotkin <[email protected]>

Author: AlexeySotkin

lib/SPIRV/LLVMToSPIRVDbgTran.cpp

@@ -150,12 +150,16 @@ void LLVMToSPIRVDbgTran::finalizeDebugValue(
   SPIRVExtInst *DV = static_cast<SPIRVExtInst *>(V);
   SPIRVBasicBlock *BB = DV->getBasicBlock();
   Value *Val = DbgValue->getVariableLocationOp(0);
-
+  DIExpression *Expr = DbgValue->getExpression();
+  if (DbgValue->getNumVariableLocationOps() > 1) {
+    Val = UndefValue::get(Val->getType());
+    Expr = DIExpression::get(M->getContext(), {});
+  }
   using namespace SPIRVDebug::Operand::DebugValue;
   SPIRVWordVec Ops(MinOperandCount);
   Ops[DebugLocalVarIdx] = transDbgEntry(DbgValue->getVariable())->getId();
   Ops[ValueIdx] = SPIRVWriter->transValue(Val, BB)->getId();
-  Ops[ExpressionIdx] = transDbgEntry(DbgValue->getExpression())->getId();
+  Ops[ExpressionIdx] = transDbgEntry(Expr)->getId();
   DV->setArguments(Ops);
 }
 

lib/SPIRV/SPIRVToLLVMDbgTran.cpp

@@ -44,9 +44,10 @@
 #include "SPIRVReader.h"
 #include "SPIRVType.h"
 
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/DIBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Module.h"
-#include "llvm/ADT/StringExtras.h"
 
 using namespace std;
 using namespace SPIRVDebug::Operand;
@@ -998,9 +999,16 @@ SPIRVToLLVMDbgTran::transDebugIntrinsic(const SPIRVExtInst *DebugInst,
   case SPIRVDebug::Value: {
     using namespace SPIRVDebug::Operand::DebugValue;
     auto LocalVar = GetLocalVar(Ops[DebugLocalVarIdx]);
-    return Builder.insertDbgValueIntrinsic(
-        GetValue(Ops[ValueIdx]), LocalVar.first,
-        GetExpression(Ops[ExpressionIdx]), LocalVar.second, BB);
+    Value *Val = GetValue(Ops[ValueIdx]);
+    DIExpression *Expr = GetExpression(Ops[ExpressionIdx]);
+    auto *DbgValIntr = Builder.insertDbgValueIntrinsic(
+        Val, LocalVar.first, Expr, LocalVar.second, BB);
+    if (Expr->getNumLocationOperands() == 1) {
+      SmallVector<ValueAsMetadata *, 1> MDs = {ValueAsMetadata::get(Val)};
+      DIArgList *AL = DIArgList::get(M->getContext(), MDs);
+      cast<DbgVariableIntrinsic>(DbgValIntr)->setRawLocation(AL);
+    }
+    return DbgValIntr;
   }
   default:
     llvm_unreachable("Unknown debug intrinsic!");

test/DebugInfo/DebugInfoLLVMArg.ll

@@ -7,12 +7,14 @@
 ; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
 ; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-LLVM
 
+; CHECK-SPIRV: Undef [[#]] [[#UNDEF:]]
 ; CHECK-SPIRV: [[#DEBUG_LOC_VAR:]] [[#]] DebugLocalVariable
 ; CHECK-SPIRV: [[#EXPR_ARG_0:]] [[#]] DebugOperation 165 0
-; CHECK-SPIRV: [[#EXPR_ARG_1:]] [[#]] DebugOperation 165 1
-; CHECK-SPIRV: [[#EXPR_ARG_2:]] [[#]] DebugOperation 1
-; CHECK-SPIRV: [[#EXPRESSION:]] [[#]] DebugExpression [[#EXPR_ARG_0]] [[#EXPR_ARG_1]] [[#EXPR_ARG_2]]
-; CHECK-SPIRV: DebugValue [[#DEBUG_LOC_VAR]] [[#]] [[#EXPRESSION]]
+; CHECK-SPIRV: [[#EXPRESSION:]] [[#]] DebugExpression [[#EXPR_ARG_0]]
+; CHECK-SPIRV: [[#EXPR_EMPTY:]] [[#]] DebugExpression{{ *$}}
+; CHECK-SPIRV: Variable [[#]] [[#VAL:]]
+; CHECK-SPIRV: DebugValue [[#DEBUG_LOC_VAR]] [[#VAL]] [[#EXPRESSION]]
+; CHECK-SPIRV: DebugValue [[#DEBUG_LOC_VAR]] [[#UNDEF]] [[#EXPR_EMPTY]]
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "spir64-unknown-unknown"
@@ -22,13 +24,14 @@ declare void @llvm.dbg.value(metadata, metadata, metadata) nounwind readnone spe
 define void @DbgIntrinsics() sanitize_memtag {
 entry:
   %x = alloca i32, align 4
-; CHECK-LLVM: call void @llvm.dbg.value(metadata i32* %x, metadata ![[#]], metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_plus))
+; CHECK-LLVM: call void @llvm.dbg.value(metadata !DIArgList(i32* %x), metadata ![[#]], metadata !DIExpression(DW_OP_LLVM_arg, 0))
+  call void @llvm.dbg.value(metadata !DIArgList(i32* %x), metadata !6, metadata !DIExpression(DW_OP_LLVM_arg, 0)), !dbg !10
+; CHECK-LLVM: call void @llvm.dbg.value(metadata i32* undef, metadata ![[#]], metadata !DIExpression())
   call void @llvm.dbg.value(metadata !DIArgList(i32* %x, i32* %x), metadata !6, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_plus)), !dbg !10
   store i32 42, i32* %x, align 4
   ret void
 }
 
-
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!8, !9}