PatchableFunction: Skip pseudos that do not create code
This fixes http://llvm.org/PR28524
llvm-svn: 275278
diff --git a/llvm/lib/CodeGen/PatchableFunction.cpp b/llvm/lib/CodeGen/PatchableFunction.cpp
index 71a727e..32468c9 100644
--- a/llvm/lib/CodeGen/PatchableFunction.cpp
+++ b/llvm/lib/CodeGen/PatchableFunction.cpp
@@ -37,6 +37,22 @@
};
}
+/// Returns true if instruction \p MI will not result in actual machine code
+/// instructions.
+static bool doesNotGeneratecode(const MachineInstr &MI) {
+ // TODO: Introduce an MCInstrDesc flag for this
+ switch (MI.getOpcode()) {
+ default: return false;
+ case TargetOpcode::IMPLICIT_DEF:
+ case TargetOpcode::KILL:
+ case TargetOpcode::CFI_INSTRUCTION:
+ case TargetOpcode::EH_LABEL:
+ case TargetOpcode::GC_LABEL:
+ case TargetOpcode::DBG_VALUE:
+ return true;
+ }
+}
+
bool PatchableFunction::runOnMachineFunction(MachineFunction &MF) {
if (!MF.getFunction()->hasFnAttribute("patchable-function"))
return false;
@@ -48,18 +64,20 @@
#endif
auto &FirstMBB = *MF.begin();
- auto &FirstMI = *FirstMBB.begin();
+ MachineBasicBlock::iterator FirstActualI = FirstMBB.begin();
+ for (; doesNotGeneratecode(*FirstActualI); ++FirstActualI)
+ assert(FirstActualI != FirstMBB.end());
auto *TII = MF.getSubtarget().getInstrInfo();
- auto MIB = BuildMI(FirstMBB, FirstMBB.begin(), FirstMI.getDebugLoc(),
+ auto MIB = BuildMI(FirstMBB, FirstActualI, FirstActualI->getDebugLoc(),
TII->get(TargetOpcode::PATCHABLE_OP))
.addImm(2)
- .addImm(FirstMI.getOpcode());
+ .addImm(FirstActualI->getOpcode());
- for (auto &MO : FirstMI.operands())
+ for (auto &MO : FirstActualI->operands())
MIB.addOperand(MO);
- FirstMI.eraseFromParent();
+ FirstActualI->eraseFromParent();
MF.ensureAlignment(4);
return true;
}