Add a pre-dispatch SjLj EH hook on the unwind edge for targets to do any

setup they require. Use this for ARM/Darwin to rematerialize the base
pointer from the frame pointer when required. rdar://8564268

llvm-svn: 116879

1 files changed, 38 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
index e16c07dfaa8..bbfd627a0cf 100644
--- a/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
+++ b/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -18,10 +18,14 @@
 #include "ARM.h"
 #include "ARMAddressingModes.h"
 #include "ARMBaseInstrInfo.h"
+#include "ARMBaseRegisterInfo.h"
+#include "ARMMachineFunctionInfo.h"
 #include "ARMRegisterInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/raw_ostream.h" // FIXME: for debug only. remove!
 using namespace llvm;
 
 namespace {
@@ -30,7 +34,7 @@ namespace {
     static char ID;
     ARMExpandPseudo() : MachineFunctionPass(ID) {}
 
-    const TargetInstrInfo *TII;
+    const ARMBaseInstrInfo *TII;
     const TargetRegisterInfo *TRI;
 
     virtual bool runOnMachineFunction(MachineFunction &Fn);
@@ -576,6 +580,38 @@ bool ARMExpandPseudo::ExpandMBB(MachineBasicBlock &MBB) {
       ModifiedOp = false;
       break;
 
+    case ARM::Int_eh_sjlj_dispatchsetup: {
+      MachineFunction &MF = *MI.getParent()->getParent();
+      const ARMBaseInstrInfo *AII =
+        static_cast<const ARMBaseInstrInfo*>(TII);
+      const ARMBaseRegisterInfo &RI = AII->getRegisterInfo();
+      // For functions using a base pointer, we rematerialize it (via the frame
+      // pointer) here since eh.sjlj.setjmp and eh.sjlj.longjmp don't do it
+      // for us. Otherwise, expand to nothing.
+      if (RI.hasBasePointer(MF)) {
+        ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+        int32_t NumBytes = AFI->getFramePtrSpillOffset();
+        unsigned FramePtr = RI.getFrameRegister(MF);
+        assert (RI.hasFP(MF) && "base pointer without frame pointer?");
+
+        if (AFI->isThumb2Function()) {
+          llvm::emitT2RegPlusImmediate(MBB, MBBI, MI.getDebugLoc(), ARM::R6,
+                                       FramePtr, -NumBytes, ARMCC::AL, 0, *TII);
+        } else if (AFI->isThumbFunction()) {
+          llvm::emitThumbRegPlusImmediate(MBB, MBBI, ARM::R6,
+                                          FramePtr, -NumBytes,
+                                          *TII, RI, MI.getDebugLoc());
+        } else {
+          llvm::emitARMRegPlusImmediate(MBB, MBBI, MI.getDebugLoc(), ARM::R6,
+                                        FramePtr, -NumBytes, ARMCC::AL, 0,
+                                        *TII);
+        }
+
+      }
+      MI.eraseFromParent();
+      break;
+    }
+
     case ARM::MOVsrl_flag:
     case ARM::MOVsra_flag: {
       // These are just fancy MOVs insructions.
@@ -953,7 +989,7 @@ bool ARMExpandPseudo::ExpandMBB(MachineBasicBlock &MBB) {
 }
 
 bool ARMExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
-  TII = MF.getTarget().getInstrInfo();
+  TII = static_cast<const ARMBaseInstrInfo*>(MF.getTarget().getInstrInfo());
   TRI = MF.getTarget().getRegisterInfo();
 
   bool Modified = false;