From af3a5420aeb421e83694745c53141683caa123cb Mon Sep 17 00:00:00 2001
From: Logan Chien <tzuhsiang.chien@gmail.com>
Date: Wed, 20 Feb 2013 12:21:33 +0000
Subject: [PATCH] Fix thumbv5e frame lowering assertion failure.

It is possible that frame pointer is not found in the
callee saved info, thus FramePtrSpillFI may be incorrect
if we don't check the result of hasFP(MF).

Besides, if we enable the stack coloring algorithm, there
will be an assertion to ensure the slot is live.  But in
the test case, %var1 is not live in the prologue of the
function, and we will get the assertion failure.

Note: There is similar code in ARMFrameLowering.cpp.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175616 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/Thumb1FrameLowering.cpp        |  9 ++++--
 .../Thumb/stack-coloring-without-frame-ptr.ll | 29 +++++++++++++++++++
 2 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/Thumb/stack-coloring-without-frame-ptr.ll

diff --git a/lib/Target/ARM/Thumb1FrameLowering.cpp b/lib/Target/ARM/Thumb1FrameLowering.cpp
index 123ada67e18..98efc16477b 100644
--- a/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -124,14 +124,17 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
   unsigned DPRCSOffset  = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
   unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
   unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
-  AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
+  bool HasFP = hasFP(MF);
+  if (HasFP)
+    AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) +
+                                NumBytes);
   AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
   AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
   AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
   NumBytes = DPRCSOffset;
 
   // Adjust FP so it point to the stack slot that contains the previous FP.
-  if (hasFP(MF)) {
+  if (HasFP) {
     AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
       .addFrameIndex(FramePtrSpillFI).addImm(0)
       .setMIFlags(MachineInstr::FrameSetup));
@@ -146,7 +149,7 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
     emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes,
                  MachineInstr::FrameSetup);
 
-  if (STI.isTargetELF() && hasFP(MF))
+  if (STI.isTargetELF() && HasFP)
     MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
                              AFI->getFramePtrSpillOffset());
 
diff --git a/test/CodeGen/Thumb/stack-coloring-without-frame-ptr.ll b/test/CodeGen/Thumb/stack-coloring-without-frame-ptr.ll
new file mode 100644
index 00000000000..3f6407a0a3c
--- /dev/null
+++ b/test/CodeGen/Thumb/stack-coloring-without-frame-ptr.ll
@@ -0,0 +1,29 @@
+; RUN: llc < %s -march=thumb -mcpu=arm1022e
+
+%iterator = type { i8**, i8**, i8**, i8*** }
+%insert_iterator = type { %deque*, %iterator }
+%deque = type { %iterator, %iterator, i8***, i32 }
+
+define i32 @test_thumbv5e_fp_elim() nounwind optsize {
+entry:
+  %var1 = alloca %iterator, align 4
+  %var2 = alloca %insert_iterator, align 4
+  %var3 = alloca %deque, align 4
+
+  %0 = bitcast %deque* %var3 to i8*
+  %1 = bitcast %iterator* %var1 to i8*
+  call void @llvm.lifetime.start(i64 16, i8* %1) nounwind
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %1, i8* %0, i32 16, i32 4, i1 false)
+  call void @llvm.lifetime.end(i64 16, i8* %1) nounwind
+
+  %2 = bitcast %insert_iterator* %var2 to i8*
+  call void @llvm.lifetime.start(i64 20, i8* %2) nounwind
+
+  ret i32 0
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
+
+declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind
-- 
2.34.1