Running with frame pointers prevented debugging, external probes and

potentially some system calls/exception handling from working.  TOS must always
link to previous frame.  This is a short term workaround until alloca scheme is
reworked.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31677 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 98ada71eb0f9a97fe3aca550b3ca06bdd34e81b5..931dac1761226db29b5be12b861f2a980a796b0f 100644 (file)
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -382,7 +382,8 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                               MachineBasicBlock::iterator I) const {
   if (hasFP(MF)) {
     // If we have a frame pointer, convert as follows:
-    // ADJCALLSTACKDOWN -> addi, r1, r1, -amount
+    // ADJCALLSTACKDOWN -> lwz r0, 0(r31)
+    //                     stwu, r0, -amount(r1)
     // ADJCALLSTACKUP   -> addi, r1, r1, amount
     MachineInstr *Old = I;
     unsigned Amount = Old->getOperand(0).getImmedValue();
@@ -395,7 +396,9 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
 
       // Replace the pseudo instruction with a new instruction...
       if (Old->getOpcode() == PPC::ADJCALLSTACKDOWN) {
-        BuildMI(MBB, I, PPC::ADDI, 2, PPC::R1).addReg(PPC::R1).addImm(-Amount);
+        BuildMI(MBB, I, PPC::LWZ, 2, PPC::R0).addImm(0).addReg(PPC::R31);
+        BuildMI(MBB, I, PPC::STWU, 3)
+                               .addReg(PPC::R0).addImm(-Amount).addReg(PPC::R1);
       } else {
         assert(Old->getOpcode() == PPC::ADJCALLSTACKUP);
         BuildMI(MBB, I, PPC::ADDI, 2, PPC::R1).addReg(PPC::R1).addImm(Amount);