[CodeGen] Fix invalid DWARF info on Win64

The relocations for `DIEEntry::EmitValue` were wrong for Win64
(emitting FK_Data_4 instead of FK_SecRel_4). This corrects that
oversight so that the DWARF data is correct in Win64 COFF files.

Fixes PR15393.

Patch by Jameson Nash <jameson@juliacomputing.com> based on a patch
by David Majnemer.

Differential Revision: https://reviews.llvm.org/D21731

llvm-svn: 289013

5 files changed, 33 insertions, 10 deletions

diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index e36903e1fae..7cff7b9b272 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -150,7 +150,7 @@ public:
   void EndCOFFSymbolDef() override;
   void EmitCOFFSafeSEH(MCSymbol const *Symbol) override;
   void EmitCOFFSectionIndex(MCSymbol const *Symbol) override;
-  void EmitCOFFSecRel32(MCSymbol const *Symbol) override;
+  void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) override;
   void emitELFSize(MCSymbol *Symbol, const MCExpr *Value) override;
   void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                         unsigned ByteAlignment) override;
@@ -614,9 +614,11 @@ void MCAsmStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
   EmitEOL();
 }
 
-void MCAsmStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
+void MCAsmStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {
   OS << "\t.secrel32\t";
   Symbol->print(OS, MAI);
+  if (Offset != 0)
+    OS << '+' << Offset;
   EmitEOL();
 }
 
diff --git a/llvm/lib/MC/MCCodeView.cpp b/llvm/lib/MC/MCCodeView.cpp
index ac1acc08b0c..ae0e50a37d7 100644
--- a/llvm/lib/MC/MCCodeView.cpp
+++ b/llvm/lib/MC/MCCodeView.cpp
@@ -200,7 +200,7 @@ void CodeViewContext::emitLineTableForFunction(MCObjectStreamer &OS,
   OS.EmitIntValue(unsigned(ModuleSubstreamKind::Lines), 4);
   OS.emitAbsoluteSymbolDiff(LineEnd, LineBegin, 4);
   OS.EmitLabel(LineBegin);
-  OS.EmitCOFFSecRel32(FuncBegin);
+  OS.EmitCOFFSecRel32(FuncBegin, /*Offset=*/0);
   OS.EmitCOFFSectionIndex(FuncBegin);
 
   // Actual line info.
diff --git a/llvm/lib/MC/MCParser/COFFAsmParser.cpp b/llvm/lib/MC/MCParser/COFFAsmParser.cpp
index 2c9f9eb0cda..f4114795a92 100644
--- a/llvm/lib/MC/MCParser/COFFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/COFFAsmParser.cpp
@@ -455,13 +455,26 @@ bool COFFAsmParser::ParseDirectiveSecRel32(StringRef, SMLoc) {
   if (getParser().parseIdentifier(SymbolID))
     return TokError("expected identifier in directive");
 
+  int64_t Offset = 0;
+  SMLoc OffsetLoc;
+  if (getLexer().is(AsmToken::Plus)) {
+    OffsetLoc = getLexer().getLoc();
+    if (getParser().parseAbsoluteExpression(Offset))
+      return true;
+  }
+
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in directive");
 
+  if (Offset < 0 || Offset > UINT32_MAX)
+    return Error(OffsetLoc,
+                 "invalid '.secrel32' directive offset, can't be less "
+                 "than zero or greater than UINT32_MAX");
+
   MCSymbol *Symbol = getContext().getOrCreateSymbol(SymbolID);
 
   Lex();
-  getStreamer().EmitCOFFSecRel32(Symbol);
+  getStreamer().EmitCOFFSecRel32(Symbol, Offset);
   return false;
 }
 
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index ebbf8116fa3..96fb566aa3a 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -125,7 +125,7 @@ void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
   if (!IsSectionRelative)
     EmitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
   else
-    EmitCOFFSecRel32(Sym);
+    EmitCOFFSecRel32(Sym, /*Offset=*/0);
 }
 
 void MCStreamer::EmitDTPRel64Value(const MCExpr *Value) {
@@ -689,8 +689,7 @@ void MCStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
 }
 
-void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
-}
+void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {}
 
 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
 /// the specified string in the output .s file.  This capability is
diff --git a/llvm/lib/MC/WinCOFFStreamer.cpp b/llvm/lib/MC/WinCOFFStreamer.cpp
index 5c6407ef1e5..6383d879403 100644
--- a/llvm/lib/MC/WinCOFFStreamer.cpp
+++ b/llvm/lib/MC/WinCOFFStreamer.cpp
@@ -195,11 +195,20 @@ void MCWinCOFFStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
   DF->getContents().resize(DF->getContents().size() + 2, 0);
 }
 
-void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
+void MCWinCOFFStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol,
+                                         uint64_t Offset) {
   MCDataFragment *DF = getOrCreateDataFragment();
-  const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
-  MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, FK_SecRel_4);
+  // Create Symbol A for the relocation relative reference.
+  const MCExpr *MCE = MCSymbolRefExpr::create(Symbol, getContext());
+  // Add the constant offset, if given.
+  if (Offset)
+    MCE = MCBinaryExpr::createAdd(
+        MCE, MCConstantExpr::create(Offset, getContext()), getContext());
+  // Build the secrel32 relocation.
+  MCFixup Fixup = MCFixup::create(DF->getContents().size(), MCE, FK_SecRel_4);
+  // Record the relocation.
   DF->getFixups().push_back(Fixup);
+  // Emit 4 bytes (zeros) to the object file.
   DF->getContents().resize(DF->getContents().size() + 4, 0);
 }