MC-COFF: Fix symbol aliases. Fixes PR8251.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115909 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 5 deletions

diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index fd1956e..6afa6db 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -157,11 +157,42 @@ void WinCOFFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
 }
 
 void WinCOFFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
-  // TODO: This is exactly the same as MachOStreamer. Consider merging into
-  // MCObjectStreamer.
-  getAssembler().getOrCreateSymbolData(*Symbol);
-  AddValueSymbols(Value);
-  Symbol->setVariableValue(Value);
+  // FIXME: This is all very ugly and depressing. What needs to happen here
+  // depends on quite a few things that are all part of relaxation, which we
+  // don't really even do.
+
+  if (Value->getKind() != MCExpr::SymbolRef) {
+    // TODO: This is exactly the same as MachOStreamer. Consider merging into

+    // MCObjectStreamer.

+    getAssembler().getOrCreateSymbolData(*Symbol);

+    AddValueSymbols(Value);

+    Symbol->setVariableValue(Value);
+  } else {
+    // FIXME: This is a horrible way to do this :(. This should really be
+    // handled after we are done with the MC* objects and immediately before
+    // writing out the object file when we know exactly what the symbol should
+    // look like in the coff symbol table. I'm not doing that now because the
+    // COFF object writer doesn't have a clearly defined separation between MC
+    // data structures, the object writers data structures, and the raw, POD,
+    // data structures that get written to disk.
+
+    // Copy over the aliased data.
+    MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
+    const MCSymbolData &RealSD = getAssembler().getOrCreateSymbolData(
+      dyn_cast<const MCSymbolRefExpr>(Value)->getSymbol());
+
+    // FIXME: This is particularly nasty because it breaks as soon as any data
+    // members of MCSymbolData change.
+    SD.CommonAlign     = RealSD.CommonAlign;
+    SD.CommonSize      = RealSD.CommonSize;
+    SD.Flags           = RealSD.Flags;
+    SD.Fragment        = RealSD.Fragment;
+    SD.Index           = RealSD.Index;
+    SD.IsExternal      = RealSD.IsExternal;
+    SD.IsPrivateExtern = RealSD.IsPrivateExtern;
+    SD.Offset          = RealSD.Offset;
+    SD.SymbolSize      = RealSD.SymbolSize;
+  }
 }
 
 void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,