Produce errors when an assignment expression would use a common symbol.
An assignment will produce a symbol with a given section and offset. There is
no way to represent something like "1 byte after a common symbol".
This matches the behavior of GNU as.
Part of PR22217.
llvm-svn: 226470
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index e3c2443..b5b7282 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -201,7 +201,17 @@
if (!A)
return nullptr;
- return &A->getSymbol();
+ const MCSymbol &ASym = A->getSymbol();
+ const MCAssembler &Asm = getAssembler();
+ const MCSymbolData &ASD = Asm.getSymbolData(ASym);
+ if (ASD.isCommon()) {
+ // FIXME: we should probably add a SMLoc to MCExpr.
+ Asm.getContext().FatalError(SMLoc(),
+ "Common symbol " + ASym.getName() +
+ " cannot be used in assignment expr");
+ }
+
+ return &ASym;
}
uint64_t MCAsmLayout::getSectionAddressSize(const MCSectionData *SD) const {