2 files changed, 27 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 5af083536d7..17bbf01c43f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1591,6 +1591,10 @@ void AsmPrinter::EmitInt32(int Value) const {
 /// .set if it avoids relocations.
 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
                                      unsigned Size) const {
+  if (!MAI->doesDwarfUseRelocationsAcrossSections())
+    if (OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size))
+      return;
+
   // Get the Hi-Lo expression.
   const MCExpr *Diff =
     MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index d82dd15df2b..836b1ced5c5 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -53,6 +53,29 @@ void MCObjectStreamer::flushPendingLabels(MCFragment *F, uint64_t FOffset) {
   }
 }
 
+bool MCObjectStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi,
+                                              const MCSymbol *Lo,
+                                              unsigned Size) {
+  // Must have symbol data.
+  if (!Assembler->hasSymbolData(*Hi) || !Assembler->hasSymbolData(*Lo))
+    return false;
+  auto &HiD = Assembler->getSymbolData(*Hi);
+  auto &LoD = Assembler->getSymbolData(*Lo);
+
+  // Must both be assigned to the same (valid) fragment.
+  if (!HiD.getFragment() || HiD.getFragment() != LoD.getFragment())
+    return false;
+
+  // Must be a data fragment.
+  if (!isa<MCDataFragment>(HiD.getFragment()))
+    return false;
+
+  assert(HiD.getOffset() >= LoD.getOffset() &&
+         "Expected Hi to be greater than Lo");
+  EmitIntValue(HiD.getOffset() - LoD.getOffset(), Size);
+  return true;
+}
+
 void MCObjectStreamer::reset() {
   if (Assembler)
     Assembler->reset();