1 files changed, 25 insertions, 4 deletions

diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 886a5f5..a8aad71 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/MC/MCSectionELF.h"
 #include <tuple>
 using namespace llvm;
 
@@ -433,12 +434,27 @@ const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
   return SD->getFragment()->getAtom();
 }
 
+// Try to fully compute Expr to an absolute value and if that fails produce
+// a relocatable expr.
+// FIXME: Should this be the behavior of EvaluateAsRelocatable itself?
+static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout,
+                     MCValue &Target) {
+  if (Expr.EvaluateAsValue(Target, &Layout))
+    if (Target.isAbsolute())
+      return true;
+  return Expr.EvaluateAsRelocatable(Target, &Layout);
+}
+
 bool MCAssembler::evaluateFixup(const MCAsmLayout &Layout,
                                 const MCFixup &Fixup, const MCFragment *DF,
                                 MCValue &Target, uint64_t &Value) const {
   ++stats::evaluateFixup;
 
-  if (!Fixup.getValue()->EvaluateAsRelocatable(Target, &Layout))
+  // FIXME: This code has some duplication with RecordRelocation. We should
+  // probably merge the two into a single callback that tries to evaluate a
+  // fixup and records a relocation if one is needed.
+  const MCExpr *Expr = Fixup.getValue();
+  if (!evaluate(*Expr, Layout, Target))
     getContext().FatalError(Fixup.getLoc(), "expected relocatable expression");
 
   bool IsPCRel = Backend.getFixupKindInfo(
@@ -782,8 +798,13 @@ void MCAssembler::writeSectionData(const MCSectionData *SD,
         assert(DF.fixup_begin() == DF.fixup_end() &&
                "Cannot have fixups in virtual section!");
         for (unsigned i = 0, e = DF.getContents().size(); i != e; ++i)
-          assert(DF.getContents()[i] == 0 &&
-                 "Invalid data value for virtual section!");
+          if (DF.getContents()[i]) {
+            if (auto *ELFSec = dyn_cast<const MCSectionELF>(&SD->getSection()))
+              report_fatal_error("non-zero initializer found in section '" +
+                  ELFSec->getSectionName() + "'");
+            else
+              report_fatal_error("non-zero initializer found in virtual section");
+          }
         break;
       }
       case MCFragment::FT_Align:
@@ -1222,7 +1243,7 @@ void MCSectionData::dump() {
   OS << "]>";
 }
 
-void MCSymbolData::dump() {
+void MCSymbolData::dump() const {
   raw_ostream &OS = llvm::errs();
 
   OS << "<MCSymbolData Symbol:" << getSymbol()