[mips] Extend MipsMCExpr class to handle %higher(sym1 - sym2 + const) and

%highest(sym1 - sym2 + const) relocations. Remove "ABS_" from VK_Mips_HI
and VK_Mips_LO enums in MipsMCExpr, to be consistent with VK_Mips_HIGHER
and VK_Mips_HIGHEST.

This change also deletes test file test/MC/Mips/higher_highest.ll and moves
its CHECK's to the new test file test/MC/Mips/higher-highest-addressing.s.
The deleted file tests that R_MIPS_HIGHER and R_MIPS_HIGHEST relocations are
emitted in the .o file. Since it uses -force-mips-long-branch option, it was
created when MipsLongBranch's implementation was emitting R_MIPS_HIGHER and
R_MIPS_HIGHEST relocations in the .o file. It was disabled when MipsLongBranch
started to directly calculate offsets.

Differential Revision: http://llvm-reviews.chandlerc.com/D3230

llvm-svn: 205522

1 files changed, 46 insertions, 3 deletions

diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.cpp
index 22ce41100a0..c7ba12d0417 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCExpr.cpp
@@ -15,17 +15,60 @@
 
 using namespace llvm;
 
+bool MipsMCExpr::isSupportedBinaryExpr(MCSymbolRefExpr::VariantKind VK,
+                                       const MCBinaryExpr *BE) {
+  switch (VK) {
+  case MCSymbolRefExpr::VK_Mips_ABS_LO:
+  case MCSymbolRefExpr::VK_Mips_ABS_HI:
+  case MCSymbolRefExpr::VK_Mips_HIGHER:
+  case MCSymbolRefExpr::VK_Mips_HIGHEST:
+    break;
+  default:
+    return false;
+  }
+
+  // We support expressions of the form "(sym1 binop1 sym2) binop2 const",
+  // where "binop2 const" is optional.
+  if (isa<MCBinaryExpr>(BE->getLHS())) {
+    if (!isa<MCConstantExpr>(BE->getRHS()))
+      return false;
+    BE = cast<MCBinaryExpr>(BE->getLHS());
+  }
+  return (isa<MCSymbolRefExpr>(BE->getLHS())
+          && isa<MCSymbolRefExpr>(BE->getRHS()));
+}
+
 const MipsMCExpr*
-MipsMCExpr::Create(VariantKind Kind, const MCExpr *Expr,
+MipsMCExpr::Create(MCSymbolRefExpr::VariantKind VK, const MCExpr *Expr,
                    MCContext &Ctx) {
+  VariantKind Kind;
+  switch (VK) {
+  case MCSymbolRefExpr::VK_Mips_ABS_LO:
+    Kind = VK_Mips_LO;
+    break;
+  case MCSymbolRefExpr::VK_Mips_ABS_HI:
+    Kind = VK_Mips_HI;
+    break;
+  case MCSymbolRefExpr::VK_Mips_HIGHER:
+    Kind = VK_Mips_HIGHER;
+    break;
+  case MCSymbolRefExpr::VK_Mips_HIGHEST:
+    Kind = VK_Mips_HIGHEST;
+    break;
+  default:
+    llvm_unreachable("Invalid kind!");
+  }
+
   return new (Ctx) MipsMCExpr(Kind, Expr);
 }
 
 void MipsMCExpr::PrintImpl(raw_ostream &OS) const {
   switch (Kind) {
   default: llvm_unreachable("Invalid kind!");
-  case VK_Mips_ABS_LO: OS << "%lo"; break;
-  case VK_Mips_ABS_HI: OS << "%hi"; break;
+  case VK_Mips_LO: OS << "%lo"; break;
+  case VK_Mips_HI: OS << "%hi"; break;
+  case VK_Mips_HIGHER: OS << "%higher"; break;
+  case VK_Mips_HIGHEST: OS << "%highest"; break;
   }
 
   OS << '(';