[XRay] support conditional return on PPC.

Summary: Conditional returns were not taken into consideration at all. Implement them by turning them into jumps and normal returns. This means there is a slightly higher performance penalty for conditional returns, but this is the best we can do, and it still disturbs little of the rest.

Reviewers: dberris, echristo

Subscribers: sanjoy, nemanjai, hiraditya, kbarton, llvm-commits

Differential Revision: https://reviews.llvm.org/D38102

llvm-svn: 314005

1 files changed, 42 insertions, 39 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp b/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
index b310493587a..cde511cb2e6 100644
--- a/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
@@ -143,45 +143,48 @@ void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
   OutMI.setOpcode(MI->getOpcode());
   
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
-    
     MCOperand MCOp;
-    switch (MO.getType()) {
-    default:
-      MI->print(errs());
-      llvm_unreachable("unknown operand type");
-    case MachineOperand::MO_Register:
-      assert(!MO.getSubReg() && "Subregs should be eliminated!");
-      assert(MO.getReg() > PPC::NoRegister &&
-             MO.getReg() < PPC::NUM_TARGET_REGS &&
-             "Invalid register for this target!");
-      MCOp = MCOperand::createReg(MO.getReg());
-      break;
-    case MachineOperand::MO_Immediate:
-      MCOp = MCOperand::createImm(MO.getImm());
-      break;
-    case MachineOperand::MO_MachineBasicBlock:
-      MCOp = MCOperand::createExpr(MCSymbolRefExpr::create(
-                                      MO.getMBB()->getSymbol(), AP.OutContext));
-      break;
-    case MachineOperand::MO_GlobalAddress:
-    case MachineOperand::MO_ExternalSymbol:
-      MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
-      break;
-    case MachineOperand::MO_JumpTableIndex:
-      MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
-      break;
-    case MachineOperand::MO_ConstantPoolIndex:
-      MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
-      break;
-    case MachineOperand::MO_BlockAddress:
-      MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
-                          isDarwin);
-      break;
-    case MachineOperand::MO_RegisterMask:
-      continue;
-    }
-    
-    OutMI.addOperand(MCOp);
+    if (LowerPPCMachineOperandToMCOperand(MI->getOperand(i), MCOp, AP,
+                                          isDarwin))
+      OutMI.addOperand(MCOp);
+  }
+}
+
+bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
+                                             MCOperand &OutMO, AsmPrinter &AP,
+                                             bool isDarwin) {
+  switch (MO.getType()) {
+  default:
+    llvm_unreachable("unknown operand type");
+  case MachineOperand::MO_Register:
+    assert(!MO.getSubReg() && "Subregs should be eliminated!");
+    assert(MO.getReg() > PPC::NoRegister &&
+           MO.getReg() < PPC::NUM_TARGET_REGS &&
+           "Invalid register for this target!");
+    OutMO = MCOperand::createReg(MO.getReg());
+    return true;
+  case MachineOperand::MO_Immediate:
+    OutMO = MCOperand::createImm(MO.getImm());
+    return true;
+  case MachineOperand::MO_MachineBasicBlock:
+    OutMO = MCOperand::createExpr(
+        MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
+    return true;
+  case MachineOperand::MO_GlobalAddress:
+  case MachineOperand::MO_ExternalSymbol:
+    OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
+    return true;
+  case MachineOperand::MO_JumpTableIndex:
+    OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
+    return true;
+  case MachineOperand::MO_ConstantPoolIndex:
+    OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
+    return true;
+  case MachineOperand::MO_BlockAddress:
+    OutMO = GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP,
+                         isDarwin);
+    return true;
+  case MachineOperand::MO_RegisterMask:
+    return false;
   }
 }