Implement .reloc (constant offset only) with support for R_MIPS_NONE and R_MIPS_32.

Summary:
Support for R_MIPS_NONE allows us to parse MIPS16's usage of .reloc.
R_MIPS_32 was included to be able to better test the directive.

Targets can add their relocations by overriding MCAsmBackend::getFixupKind().

Subscribers: grosbach, rafael, majnemer, dsanders, llvm-commits

Differential Revision: http://reviews.llvm.org/D13659

llvm-svn: 252888

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index c47e2162b63..d0a7dafa15b 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -416,6 +416,26 @@ void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
   DF->getContents().resize(DF->getContents().size() + 8, 0);
 }
 
+bool MCObjectStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
+                                          const MCExpr *Expr, SMLoc Loc) {
+  int64_t OffsetValue;
+  if (!Offset.evaluateAsAbsolute(OffsetValue))
+    llvm_unreachable("Offset is not absolute");
+
+  MCDataFragment *DF = getOrCreateDataFragment();
+  flushPendingLabels(DF, DF->getContents().size());
+
+  MCFixupKind Kind;
+  if (!Assembler->getBackend().getFixupKind(Name, Kind))
+    return true;
+
+  if (Expr == nullptr)
+    Expr =
+        MCSymbolRefExpr::create(getContext().createTempSymbol(), getContext());
+  DF->getFixups().push_back(MCFixup::create(OffsetValue, Expr, Kind, Loc));
+  return false;
+}
+
 void MCObjectStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
   const MCSection *Sec = getCurrentSection().first;
   assert(Sec && "need a section");