Support DW_OP_LLVM_arg DWARF operation (#1279)

Author: vmaksimo

lib/SPIRV/libSPIRV/SPIRV.debug.h

@@ -264,7 +264,8 @@ enum ExpressionOpCode {
   RegvalType        = 161,
   DerefType         = 162,
   XderefType        = 163,
-  Reinterpret       = 164
+  Reinterpret       = 164,
+  LLVMArg           = 165,
 };
 
 enum ImportedEntityTag {
@@ -756,6 +757,7 @@ static std::map<ExpressionOpCode, unsigned> OpCountMap {
   // { DerefType,          3 },
   // { XderefType,         3 },
   // { Reinterpret,        2 },
+  { LLVMArg,            2 },
 };
 }
 
@@ -1002,6 +1004,7 @@ inline void DbgExpressionOpCodeMap::init() {
   add(dwarf::DW_OP_xderef_size,         SPIRVDebug::XderefSize );
   add(dwarf::DW_OP_nop,                 SPIRVDebug::Nop);
   add(dwarf::DW_OP_push_object_address, SPIRVDebug::PushObjectAddress );
+  add(dwarf::DW_OP_LLVM_arg,            SPIRVDebug::LLVMArg);
 }
 
 typedef SPIRVMap<dwarf::Tag, SPIRVDebug::ImportedEntityTag>

test/DebugInfo/DebugInfoLLVMArg.ll

@@ -0,0 +1,45 @@
+; This test checks that DW_OP_LLVM_arg operation goes through round trip translation correctly.
+
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -o %t.spv --spirv-allow-extra-diexpressions
+; RUN: llvm-spirv %t.spv -to-text -o %t.spt
+; RUN: FileCheck < %t.spt %s --check-prefix=CHECK-SPIRV
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
+; RUN: llvm-dis < %t.rev.bc | FileCheck %s --check-prefix=CHECK-LLVM
+
+; 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]]
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "spir64-unknown-unknown"
+
+declare void @llvm.dbg.value(metadata, metadata, metadata) nounwind readnone speculatable
+
+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))
+  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}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "stack-tagging.cc", directory: "/tmp")
+!2 = !{}
+!3 = distinct !DISubprogram(name: "DbgIntrinsics", linkageName: "DbgIntrinsics", scope: !1, file: !1, line: 3, type: !4, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!4 = !DISubroutineType(types: !5)
+!5 = !{null}
+!6 = !DILocalVariable(name: "x", scope: !3, file: !1, line: 4, type: !7)
+!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !DILocation(line: 1, column: 2, scope: !3)