Added support in MC for Directional Local Labels.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103989 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 50 insertions, 9 deletions

diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
index 1183312..e74eac5 100644
--- a/lib/MC/MCParser/AsmLexer.cpp
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -132,11 +132,6 @@ AsmToken AsmLexer::LexLineComment() {
 ///   Decimal integer: [1-9][0-9]*
 /// TODO: FP literal.
 AsmToken AsmLexer::LexDigit() {
-  if (*CurPtr == ':')
-    return ReturnError(TokStart, "FIXME: local label not implemented");
-  if (*CurPtr == 'f' || *CurPtr == 'b')
-    return ReturnError(TokStart, "FIXME: directional label not implemented");
-  
   // Decimal integer: [1-9][0-9]*
   if (CurPtr[-1] != '0') {
     while (isdigit(*CurPtr))
@@ -158,6 +153,13 @@ AsmToken AsmLexer::LexDigit() {
   
   if (*CurPtr == 'b') {
     ++CurPtr;
+    // See if we actually have "0b" as part of something like "jmp 0b\n"
+    if (CurPtr[0] == '\n') {
+      --CurPtr;
+      StringRef Result(TokStart, CurPtr - TokStart);
+      ++CurPtr;
+      return AsmToken(AsmToken::Integer, Result, 0);
+    }
     const char *NumStart = CurPtr;
     while (CurPtr[0] == '0' || CurPtr[0] == '1')
       ++CurPtr;
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 2a60a67..6a89df1 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -214,11 +214,28 @@ bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
     Res = MCSymbolRefExpr::Create(Sym, Variant, getContext());
     return false;
   }
-  case AsmToken::Integer:
-    Res = MCConstantExpr::Create(getTok().getIntVal(), getContext());
+  case AsmToken::Integer: {
+    SMLoc Loc = getTok().getLoc();
+    int64_t IntVal = getTok().getIntVal();
+    Res = MCConstantExpr::Create(IntVal, getContext());
     EndLoc = Lexer.getLoc();
     Lex(); // Eat token.
+    // Look for 'b' or 'f' following an Integer as a directional label
+    if (Lexer.getKind() == AsmToken::Identifier) {
+      StringRef IDVal = getTok().getString();
+      if (IDVal == "f" || IDVal == "b"){
+        MCSymbol *Sym = Ctx.GetDirectionalLocalSymbol(IntVal,
+                                                      IDVal == "f" ? 1 : 0);
+        Res = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_None,
+                                      getContext());
+        if(IDVal == "b" && Sym->isUndefined())
+          return Error(Loc, "invalid reference to undefined symbol");
+        EndLoc = Lexer.getLoc();
+        Lex(); // Eat identifier.
+      }
+    }
     return false;
+  }
   case AsmToken::Dot: {
     // This is a '.' reference, which references the current PC.  Emit a
     // temporary label to the streamer and refer to it.
@@ -422,7 +439,25 @@ bool AsmParser::ParseStatement() {
   AsmToken ID = getTok();
   SMLoc IDLoc = ID.getLoc();
   StringRef IDVal;
-  if (ParseIdentifier(IDVal)) {
+  int64_t LocalLabelVal = -1;
+  // GUESS allow an integer followed by a ':' as a directional local label
+  if (Lexer.is(AsmToken::Integer)) {
+    LocalLabelVal = getTok().getIntVal();
+    if (LocalLabelVal < 0) {
+      if (!TheCondState.Ignore)
+        return TokError("unexpected token at start of statement");
+      IDVal = "";
+    }
+    else {
+      IDVal = getTok().getString();
+      Lex(); // Consume the integer token to be used as an identifier token.
+      if (Lexer.getKind() != AsmToken::Colon) {
+	  if (!TheCondState.Ignore)
+	    return TokError("unexpected token at start of statement");
+      }
+    }
+  }
+  else if (ParseIdentifier(IDVal)) {
     if (!TheCondState.Ignore)
       return TokError("unexpected token at start of statement");
     IDVal = "";
@@ -459,7 +494,11 @@ bool AsmParser::ParseStatement() {
     // FIXME: Diagnostics. Note the location of the definition as a label.
     // FIXME: This doesn't diagnose assignment to a symbol which has been
     // implicitly marked as external.
-    MCSymbol *Sym = CreateSymbol(IDVal);
+    MCSymbol *Sym;
+    if (LocalLabelVal == -1)
+      Sym = CreateSymbol(IDVal);
+    else
+      Sym = Ctx.CreateDirectionalLocalSymbol(LocalLabelVal);
     if (!Sym->isUndefined() || Sym->isVariable())
       return Error(IDLoc, "invalid symbol redefinition");