llvm-mc: Diagnose misuse (mix) of defined symbols and labels.
- For example, we diagnose errors on:
--
a:
a = 10
--
- For now we reject code like:
--
.long a
a = 10
--
which "as" accepts (on Darwin).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74476 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/AsmParser.cpp b/tools/llvm-mc/AsmParser.cpp
index 9121797..4cb515b 100644
--- a/tools/llvm-mc/AsmParser.cpp
+++ b/tools/llvm-mc/AsmParser.cpp
@@ -17,6 +17,7 @@
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
@@ -82,12 +83,19 @@
return true;
Res = new AsmUnaryExpr(AsmUnaryExpr::LNot, Res);
return false;
- case asmtok::Identifier:
+ case asmtok::Identifier: {
// This is a label, this should be parsed as part of an expression, to
// handle things like LFOO+4.
- Res = new AsmSymbolRefExpr(Ctx.GetOrCreateSymbol(Lexer.getCurStrVal()));
+ MCSymbol *Sym = Ctx.GetOrCreateSymbol(Lexer.getCurStrVal());
+
+ // If this is use of an undefined symbol then mark it external.
+ if (!Sym->getSection() && !Ctx.GetSymbolValue(Sym))
+ Sym->setExternal(true);
+
+ Res = new AsmSymbolRefExpr(Sym);
Lexer.Lex(); // Eat identifier.
return false;
+ }
case asmtok::IntVal:
Res = new AsmConstantExpr(Lexer.getCurIntVal());
Lexer.Lex(); // Eat identifier.
@@ -270,16 +278,28 @@
// Consume the identifier, see what is after it.
switch (Lexer.Lex()) {
- case asmtok::Colon:
+ case asmtok::Colon: {
// identifier ':' -> Label.
Lexer.Lex();
+
+ // Diagnose attempt to use a variable as a label.
+ //
+ // 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 = Ctx.GetOrCreateSymbol(IDVal);
+ if (Sym->getSection())
+ return Error(IDLoc, "invalid symbol redefinition");
+ if (Ctx.GetSymbolValue(Sym))
+ return Error(IDLoc, "symbol already used as assembler variable");
// Since we saw a label, create a symbol and emit it.
// FIXME: If the label starts with L it is an assembler temporary label.
// Why does the client of this api need to know this?
- Out.EmitLabel(Ctx.GetOrCreateSymbol(IDVal));
-
+ Out.EmitLabel(Sym);
+
return ParseStatement();
+ }
case asmtok::Equal:
// identifier '=' ... -> assignment statement
@@ -440,6 +460,9 @@
}
bool AsmParser::ParseAssignment(const char *Name, bool IsDotSet) {
+ // FIXME: Use better location, we should use proper tokens.
+ SMLoc EqualLoc = Lexer.getLoc();
+
int64_t Value;
if (ParseAbsoluteExpression(Value))
return true;
@@ -450,9 +473,20 @@
// Eat the end of statement marker.
Lexer.Lex();
- // Get the symbol for this name.
+ // Diagnose assignment to a label.
+ //
+ // 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.
// FIXME: Handle '.'.
+ // FIXME: Diagnose assignment to protected identifier (e.g., register name).
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name);
+ if (Sym->getSection())
+ return Error(EqualLoc, "invalid assignment to symbol emitted as a label");
+ if (Sym->isExternal())
+ return Error(EqualLoc, "invalid assignment to external symbol");
+
+ // Do the assignment.
Out.EmitAssignment(Sym, MCValue::get(Value), IsDotSet);
return false;