AsmParser: Recognize DW_TAG_* constants

Recognize `DW_TAG_` constants in assembly, and output it by default for
`GenericDebugNode`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228042 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AsmParser/LLLexer.cpp

@@ -738,6 +738,12 @@ lltok::Kind LLLexer::LexIdentifier() {
   INSTKEYWORD(landingpad,     LandingPad);
 #undef INSTKEYWORD
 
+  if (Len >= strlen("DW_TAG_") &&
+      !memcmp(StartChar, "DW_TAG_", strlen("DW_TAG_"))) {
+    StrVal.assign(StartChar, CurPtr);
+    return lltok::DwarfTag;
+  }
+
   // Check for [us]0x[0-9A-Fa-f]+ which are Hexadecimal constant generated by
   // the CFE to avoid forcing it to deal with 64-bit numbers.
   if ((TokStart[0] == 'u' || TokStart[0] == 's') &&

lib/AsmParser/LLParser.cpp

@@ -24,6 +24,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/ValueSymbolTable.h"
+#include "llvm/Support/Dwarf.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/raw_ostream.h"
@@ -2936,6 +2937,28 @@ bool LLParser::ParseMDField(LocTy Loc, StringRef Name,
   return false;
 }
 
+bool LLParser::ParseMDField(LocTy Loc, StringRef Name, DwarfTagField &Result) {
+  if (Lex.getKind() == lltok::APSInt)
+    return ParseMDField(Loc, Name,
+                        static_cast<MDUnsignedField<uint32_t> &>(Result));
+
+  if (Result.Seen)
+    return Error(Loc,
+                 "field '" + Name + "' cannot be specified more than once");
+
+  if (Lex.getKind() != lltok::DwarfTag)
+    return TokError("expected DWARF tag");
+
+  unsigned Tag = dwarf::getTag(Lex.getStrVal());
+  if (Tag == dwarf::DW_TAG_invalid)
+    return TokError("invalid DWARF tag" + Twine(" '") + Lex.getStrVal() + "'");
+  assert(Tag < 1u << 16 && "Expected valid DWARF tag");
+
+  Result.assign(Tag);
+  Lex.Lex();
+  return false;
+}
+
 bool LLParser::ParseMDField(LocTy Loc, StringRef Name, MDField &Result) {
   Metadata *MD;
   if (ParseMetadata(MD, nullptr))
@@ -3056,7 +3079,7 @@ bool LLParser::ParseMDLocation(MDNode *&Result, bool IsDistinct) {
 ///   ::= !GenericDebugNode(tag: 15, header: "...", operands: {...})
 bool LLParser::ParseGenericDebugNode(MDNode *&Result, bool IsDistinct) {
 #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
-  REQUIRED(tag, MDUnsignedField<uint32_t>, (0, ~0u >> 16));                    \
+  REQUIRED(tag, DwarfTagField, );                                              \
   OPTIONAL(header, MDStringField, );                                           \
   OPTIONAL(operands, MDFieldList, );
   PARSE_MD_FIELDS();

lib/AsmParser/LLParser.h

@@ -102,6 +102,9 @@ namespace llvm {
                     NumTy Max = std::numeric_limits<NumTy>::max())
         : ImplTy(Default), Max(Max) {}
   };
+  struct DwarfTagField : public MDUnsignedField<uint32_t> {
+    DwarfTagField() : MDUnsignedField<uint32_t>(0, ~0u >> 16) {}
+  };
   struct MDField : public MDFieldImpl<Metadata *> {
     MDField() : ImplTy(nullptr) {}
   };
@@ -427,6 +430,7 @@ namespace llvm {
 
     bool ParseMDField(LocTy Loc, StringRef Name,
                       MDUnsignedField<uint32_t> &Result);
+    bool ParseMDField(LocTy Loc, StringRef Name, DwarfTagField &Result);
     bool ParseMDField(LocTy Loc, StringRef Name, MDField &Result);
     bool ParseMDField(LocTy Loc, StringRef Name, MDStringField &Result);
     bool ParseMDField(LocTy Loc, StringRef Name, MDFieldList &Result);

lib/AsmParser/LLToken.h

@@ -198,6 +198,7 @@ namespace lltok {
     LocalVar,          // %foo %"foo"
     MetadataVar,       // !foo
     StringConstant,    // "foo"
+    DwarfTag,          // DW_TAG_foo (includes "DW_TAG_")
 
     // Type valued tokens (TyVal).
     Type,