ms-inline-asm: Add a sema callback for looking up label names

The implementation of the callback in clang's Sema will return an
internal name for labels.

Test Plan: Will be tested in clang.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4587

llvm-svn: 218229

include/llvm/MC/MCParser/MCAsmParser.h

@@ -35,6 +35,7 @@ public:
   void *OpDecl;
   bool IsVarDecl;
   unsigned Length, Size, Type;
+  StringRef InternalName;
 
   void clear() {
     OpDecl = nullptr;
@@ -42,6 +43,7 @@ public:
     Length = 1;
     Size = 0;
     Type = 0;
+    InternalName = "";
   }
 };
 
@@ -52,6 +54,9 @@ public:
   virtual void *LookupInlineAsmIdentifier(StringRef &LineBuf,
                                           InlineAsmIdentifierInfo &Info,
                                           bool IsUnevaluatedContext) = 0;
+  virtual StringRef LookupInlineAsmLabel(StringRef Identifier, SourceMgr &SM,
+                                         SMLoc Location, bool Create)
+  { return nullptr; }
 
   virtual bool LookupInlineAsmField(StringRef Base, StringRef Member,
                                     unsigned &Offset) = 0;

include/llvm/MC/MCTargetAsmParser.h

@@ -38,6 +38,7 @@ enum AsmRewriteKind {
   AOK_Input,          // Rewrite in terms of $N.
   AOK_Output,         // Rewrite in terms of $N.
   AOK_SizeDirective,  // Add a sizing directive (e.g., dword ptr).
+  AOK_Label,          // Rewrite local labels.
   AOK_Skip            // Skip emission (e.g., offset/type operators).
 };
 
@@ -51,6 +52,7 @@ const char AsmRewritePrecedence [] = {
   2, // AOK_Input
   2, // AOK_Output
   4, // AOK_SizeDirective
+  1, // AOK_Label
   1  // AOK_Skip
 };
 
@@ -59,9 +61,12 @@ struct AsmRewrite {
   SMLoc Loc;
   unsigned Len;
   unsigned Val;
+  StringRef Label;
 public:
   AsmRewrite(AsmRewriteKind kind, SMLoc loc, unsigned len = 0, unsigned val = 0)
     : Kind(kind), Loc(loc), Len(len), Val(val) {}
+  AsmRewrite(AsmRewriteKind kind, SMLoc loc, unsigned len, StringRef label)
+    : Kind(kind), Loc(loc), Len(len), Val(0), Label(label) {}
 };
 
 struct ParseInstructionInfo {

lib/MC/MCParser/AsmParser.cpp

@@ -238,7 +238,8 @@ public:
 
 private:
 
-  bool parseStatement(ParseStatementInfo &Info);
+  bool parseStatement(ParseStatementInfo &Info,
+                      MCAsmParserSemaCallback *SI);
   void eatToEndOfLine();
   bool parseCppHashLineFilenameComment(const SMLoc &L);
 
@@ -640,7 +641,7 @@ bool AsmParser::Run(bool NoInitialTextSection, bool NoFinalize) {
   // While we have input, parse each statement.
   while (Lexer.isNot(AsmToken::Eof)) {
     ParseStatementInfo Info;
-    if (!parseStatement(Info))
+    if (!parseStatement(Info, nullptr))
       continue;
 
     // We had an error, validate that one was emitted and recover by skipping to
@@ -1185,7 +1186,8 @@ bool AsmParser::parseBinOpRHS(unsigned Precedence, const MCExpr *&Res,
 ///   ::= EndOfStatement
 ///   ::= Label* Directive ...Operands... EndOfStatement
 ///   ::= Label* Identifier OperandList* EndOfStatement
-bool AsmParser::parseStatement(ParseStatementInfo &Info) {
+bool AsmParser::parseStatement(ParseStatementInfo &Info,
+                               MCAsmParserSemaCallback *SI) {
   if (Lexer.is(AsmToken::EndOfStatement)) {
     Out.AddBlankLine();
     Lex();
@@ -1295,9 +1297,16 @@ bool AsmParser::parseStatement(ParseStatementInfo &Info) {
     // FIXME: This doesn't diagnose assignment to a symbol which has been
     // implicitly marked as external.
     MCSymbol *Sym;
-    if (LocalLabelVal == -1)
+    if (LocalLabelVal == -1) {
+      if (ParsingInlineAsm && SI) {
+        StringRef RewrittenLabel = SI->LookupInlineAsmLabel(IDVal, getSourceManager(), IDLoc, true);
+        assert(RewrittenLabel.size() && "We should have an internal name here.");
+        Info.AsmRewrites->push_back(AsmRewrite(AOK_Label, IDLoc,
+                                               IDVal.size(), RewrittenLabel));
+        IDVal = RewrittenLabel;
+      }
       Sym = getContext().GetOrCreateSymbol(IDVal);
-    else
+    } else
       Sym = Ctx.CreateDirectionalLocalSymbol(LocalLabelVal);
     if (!Sym->isUndefined() || Sym->isVariable())
       return Error(IDLoc, "invalid symbol redefinition");
@@ -4541,7 +4550,7 @@ bool AsmParser::parseMSInlineAsm(
   unsigned OutputIdx = 0;
   while (getLexer().isNot(AsmToken::Eof)) {
     ParseStatementInfo Info(&AsmStrRewrites);
-    if (parseStatement(Info))
+    if (parseStatement(Info, &SI))
       return true;
 
     if (Info.ParseError)
@@ -4667,6 +4676,9 @@ bool AsmParser::parseMSInlineAsm(
     case AOK_ImmPrefix:
       OS << "$$";
       break;
+    case AOK_Label:
+      OS << Ctx.getAsmInfo()->getPrivateGlobalPrefix() << AR.Label;
+      break;
     case AOK_Input:
       OS << '$' << InputIdx++;
       break;

lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -1047,6 +1047,12 @@ std::unique_ptr<X86Operand> X86AsmParser::CreateMemForInlineAsm(
         InstInfo->AsmRewrites->push_back(AsmRewrite(AOK_SizeDirective, Start,
                                                     /*Len=*/0, Size));
     }
+    if (!Info.InternalName.empty()) {
+      // Push a rewrite for replacing the identifier name with the internal name.
+      InstInfo->AsmRewrites->push_back(AsmRewrite(AOK_Label, Start,
+                                                  End.getPointer() - Start.getPointer(),
+                                                  Info.InternalName));
+    }
   }
 
   // When parsing inline assembly we set the base register to a non-zero value
@@ -1320,9 +1326,11 @@ bool X86AsmParser::ParseIntelIdentifier(const MCExpr *&Val,
   Val = nullptr;
 
   StringRef LineBuf(Identifier.data());
-  SemaCallback->LookupInlineAsmIdentifier(LineBuf, Info, IsUnevaluatedOperand);
+  void *Result =
+    SemaCallback->LookupInlineAsmIdentifier(LineBuf, Info, IsUnevaluatedOperand);
 
   const AsmToken &Tok = Parser.getTok();
+  SMLoc Loc = Tok.getLoc();
 
   // Advance the token stream until the end of the current token is
   // after the end of what the frontend claimed.
@@ -1334,9 +1342,17 @@ bool X86AsmParser::ParseIntelIdentifier(const MCExpr *&Val,
     assert(End.getPointer() <= EndPtr && "frontend claimed part of a token?");
     if (End.getPointer() == EndPtr) break;
   }
+  Identifier = LineBuf;
+
+  // If the identifier lookup was unsuccessful, assume that we are dealing with
+  // a label.
+  if (!Result) {
+    Identifier = SemaCallback->LookupInlineAsmLabel(Identifier, getSourceManager(), Loc, false);
+    assert(Identifier.size() && "We should have an internal name here.");
+    Info.InternalName = Identifier;
+  }
 
   // Create the symbol reference.
-  Identifier = LineBuf;
   MCSymbol *Sym = getContext().GetOrCreateSymbol(Identifier);
   MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
   Val = MCSymbolRefExpr::Create(Sym, Variant, getParser().getContext());