implement mc asmparser support for '.', which gets the
current PC. rdar://7834775
We now produce an identical .o file compared to the cctools
assembler for something like this:
_f0:
L0:
jmp L1
.long . - L0
L1:
jmp A
.long . - L1
.zerofill __DATA,_bss,A,0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101227 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/MC/MCParser/MCAsmLexer.h b/include/llvm/MC/MCParser/MCAsmLexer.h
index 043c363..075b69b 100644
--- a/include/llvm/MC/MCParser/MCAsmLexer.h
+++ b/include/llvm/MC/MCParser/MCAsmLexer.h
@@ -42,7 +42,7 @@
Plus, Minus, Tilde,
Slash, // '/'
LParen, RParen, LBrac, RBrac, LCurly, RCurly,
- Star, Comma, Dollar, Equal, EqualEqual,
+ Star, Dot, Comma, Dollar, Equal, EqualEqual,
Pipe, PipePipe, Caret,
Amp, AmpAmp, Exclaim, ExclaimEqual, Percent, Hash,
diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
index 22c8d76..1183312 100644
--- a/lib/MC/MCParser/AsmLexer.cpp
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -74,6 +74,11 @@
while (isalnum(*CurPtr) || *CurPtr == '_' || *CurPtr == '$' ||
*CurPtr == '.' || *CurPtr == '@')
++CurPtr;
+
+ // Handle . as a special case.
+ if (CurPtr == TokStart+1 && TokStart[0] == '.')
+ return AsmToken(AsmToken::Dot, StringRef(TokStart, 1));
+
return AsmToken(AsmToken::Identifier, StringRef(TokStart, CurPtr - TokStart));
}
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 7120d91..e2c43f4 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -209,6 +209,7 @@
/// primaryexpr ::= (parenexpr
/// primaryexpr ::= symbol
/// primaryexpr ::= number
+/// primaryexpr ::= '.'
/// primaryexpr ::= ~,+,- primaryexpr
bool AsmParser::ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc) {
switch (Lexer.getKind()) {
@@ -253,6 +254,17 @@
EndLoc = Lexer.getLoc();
Lex(); // Eat token.
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.
+ MCSymbol *Sym = Ctx.CreateTempSymbol();
+ Out.EmitLabel(Sym);
+ Res = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_None, getContext());
+ EndLoc = Lexer.getLoc();
+ Lex(); // Eat identifier.
+ return false;
+ }
+
case AsmToken::LParen:
Lex(); // Eat the '('.
return ParseParenExpr(Res, EndLoc);
diff --git a/test/MC/AsmParser/exprs.s b/test/MC/AsmParser/exprs.s
index 62b11c2..d9a248c 100644
--- a/test/MC/AsmParser/exprs.s
+++ b/test/MC/AsmParser/exprs.s
@@ -61,3 +61,14 @@
movw $8, (42)+66(%eax)
+
+// "." support:
+_f0:
+L0:
+ jmp L1
+ .long . - L0
+L1:
+ jmp A
+ .long . - L1
+
+ .zerofill __DATA,_bss,A,0