[AArch64] Decorate AArch64 instrs with OPERAND_PCREL

Summary:
This is a canonical way to teach objdump to print the target
symbols for branches when disassembling AArch64 code.

Reviewers: evandro, t.p.northover, espindola

Reviewed By: t.p.northover

Differential Revision: https://reviews.llvm.org/D44851

llvm-svn: 328638

2 files changed, 27 insertions, 1 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index 8839b610903..e1dcd1b7465 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -1244,6 +1244,7 @@ def am_brcond : Operand<OtherVT> {
   let DecoderMethod = "DecodePCRelLabel19";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = PCRelLabel19Operand;
+  let OperandType = "OPERAND_PCREL";
 }
 
 class BranchCond : I<(outs), (ins ccode:$cond, am_brcond:$target),
@@ -1299,6 +1300,7 @@ def am_tbrcond : Operand<OtherVT> {
   let EncoderMethod = "getTestBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = BranchTarget14Operand;
+  let OperandType = "OPERAND_PCREL";
 }
 
 // AsmOperand classes to emit (or not) special diagnostics
@@ -1375,11 +1377,13 @@ def am_b_target : Operand<OtherVT> {
   let EncoderMethod = "getBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = BranchTarget26Operand;
+  let OperandType = "OPERAND_PCREL";
 }
 def am_bl_target : Operand<i64> {
   let EncoderMethod = "getBranchTargetOpValue";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = BranchTarget26Operand;
+  let OperandType = "OPERAND_PCREL";
 }
 
 class BImm<bit op, dag iops, string asm, list<dag> pattern>
@@ -2667,6 +2671,7 @@ def am_ldrlit : Operand<iPTR> {
   let DecoderMethod = "DecodePCRelLabel19";
   let PrintMethod = "printAlignedLabel";
   let ParserMatchClass = PCRelLabel19Operand;
+  let OperandType = "OPERAND_PCREL";
 }
 
 let mayLoad = 1, mayStore = 0, hasSideEffects = 0 in
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
index c3458d625b8..37257d8328c 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
@@ -131,8 +131,29 @@ createWinCOFFStreamer(MCContext &Ctx, std::unique_ptr<MCAsmBackend> &&TAB,
                                       IncrementalLinkerCompatible);
 }
 
+namespace {
+
+class AArch64MCInstrAnalysis : public MCInstrAnalysis {
+public:
+  AArch64MCInstrAnalysis(const MCInstrInfo *Info) : MCInstrAnalysis(Info) {}
+
+  bool evaluateBranch(const MCInst &Inst, uint64_t Addr, uint64_t Size,
+                      uint64_t &Target) const override {
+    if (Inst.getNumOperands() == 0 ||
+        Info->get(Inst.getOpcode()).OpInfo[0].OperandType !=
+            MCOI::OPERAND_PCREL)
+      return false;
+
+    int64_t Imm = Inst.getOperand(0).getImm() * 4;
+    Target = Addr + Imm;
+    return true;
+  }
+};
+
+} // end anonymous namespace
+
 static MCInstrAnalysis *createAArch64InstrAnalysis(const MCInstrInfo *Info) {
-  return new MCInstrAnalysis(Info);
+  return new AArch64MCInstrAnalysis(Info);
 }
 
 // Force static initialization.