Use 32-bit ebp for NaCl64 in a limited case: llvm.frameaddress.

Summary:
Follow up to [x32] "Use ebp/esp as frame and stack pointer":
http://reviews.llvm.org/D4617

In that earlier patch, NaCl64 was made to always use rbp.
That's needed for most cases because rbp should hold a full
64-bit address within the NaCl sandbox so that load/stores
off of rbp don't require sandbox adjustment (zeroing the top
32-bits, then filling those by adding r15).

However, llvm.frameaddress returns a pointer and pointers
are 32-bit for NaCl64. In this case, use ebp instead, which
will make the register copy type check. A similar mechanism
may be needed for llvm.eh.return, but is not added in this change.

Test Plan: test/CodeGen/X86/frameaddr.ll

Reviewers: dschuff, nadav

Subscribers: jfb, llvm-commits

Differential Revision: http://reviews.llvm.org/D6514

llvm-svn: 223510

4 files changed, 14 insertions, 4 deletions

diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index ed3a0a5939c..6c915cfaf5c 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -2143,14 +2143,14 @@ bool X86FastISel::fastLowerIntrinsicCall(const IntrinsicInst *II) {
     case MVT::i64: Opc = X86::MOV64rm; RC = &X86::GR64RegClass; break;
     }
 
-    // This needs to be set before we call getFrameRegister, otherwise we get
-    // the wrong frame register.
+    // This needs to be set before we call getPtrSizedFrameRegister, otherwise
+    // we get the wrong frame register.
     MachineFrameInfo *MFI = FuncInfo.MF->getFrameInfo();
     MFI->setFrameAddressIsTaken(true);
 
     const X86RegisterInfo *RegInfo = static_cast<const X86RegisterInfo *>(
         TM.getSubtargetImpl()->getRegisterInfo());
-    unsigned FrameReg = RegInfo->getFrameRegister(*(FuncInfo.MF));
+    unsigned FrameReg = RegInfo->getPtrSizedFrameRegister(*(FuncInfo.MF));
     assert(((FrameReg == X86::RBP && VT == MVT::i64) ||
             (FrameReg == X86::EBP && VT == MVT::i32)) &&
            "Invalid Frame Register!");
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 6d5a10feab1..a0009eb9a8d 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -17636,7 +17636,8 @@ SDValue X86TargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
   const X86RegisterInfo *RegInfo = static_cast<const X86RegisterInfo *>(
       DAG.getSubtarget().getRegisterInfo());
-  unsigned FrameReg = RegInfo->getFrameRegister(DAG.getMachineFunction());
+  unsigned FrameReg = RegInfo->getPtrSizedFrameRegister(
+      DAG.getMachineFunction());
   assert(((FrameReg == X86::RBP && VT == MVT::i64) ||
           (FrameReg == X86::EBP && VT == MVT::i32)) &&
          "Invalid Frame Register!");
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index a4a366da893..09e651cebfb 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -535,6 +535,14 @@ unsigned X86RegisterInfo::getFrameRegister(const MachineFunction &MF) const {
   return TFI->hasFP(MF) ? FramePtr : StackPtr;
 }
 
+unsigned X86RegisterInfo::getPtrSizedFrameRegister(
+    const MachineFunction &MF) const {
+  unsigned FrameReg = getFrameRegister(MF);
+  if (Subtarget.isTarget64BitILP32())
+    FrameReg = getX86SubSuperRegister(FrameReg, MVT::i32, false);
+  return FrameReg;
+}
+
 namespace llvm {
 unsigned getX86SubSuperRegister(unsigned Reg, MVT::SimpleValueType VT,
                                 bool High) {
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.h b/llvm/lib/Target/X86/X86RegisterInfo.h
index cc0a7b2d82c..406b1fcd8d0 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.h
+++ b/llvm/lib/Target/X86/X86RegisterInfo.h
@@ -122,6 +122,7 @@ public:
 
   // Debug information queries.
   unsigned getFrameRegister(const MachineFunction &MF) const override;
+  unsigned getPtrSizedFrameRegister(const MachineFunction &MF) const;
   unsigned getStackRegister() const { return StackPtr; }
   unsigned getBaseRegister() const { return BasePtr; }
   // FIXME: Move to FrameInfok