From d9e64b6c08e32ee522e8a1f76c88a0c2bb028b90 Mon Sep 17 00:00:00 2001
From: Adrian Prantl <aprantl@apple.com>
Date: Mon, 22 Dec 2014 23:09:14 +0000
Subject: [PATCH] Thumb1 frame lowering: Mark CFI instructions with the
 FrameSetup flag.

Followup to r224294:

ARM/AArch64: Attach the FrameSetup MIFlag to CFI instructions.
Debug info marks the first instruction without the FrameSetup flag
as being the end of the function prologue. Any CFI instructions in the
middle of the function prologue would cause debug info to end the prologue
too early and worse, attach the line number of the CFI instruction, which
incidentally is often 0.

llvm-svn: 224743
---
 llvm/lib/Target/ARM/Thumb1FrameLowering.cpp | 21 ++++++++++++++-------
 llvm/test/DebugInfo/ARM/cfi-eof-prologue.ll |  3 ++-
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
index 6deab4f..13f9358 100644
--- a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -124,7 +124,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
     unsigned CFIIndex = MMI.addFrameInst(
         MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset));
     BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-        .addCFIIndex(CFIIndex);
+        .addCFIIndex(CFIIndex)
+        .setMIFlags(MachineInstr::FrameSetup);
   }
 
   if (!AFI->hasStackFrame()) {
@@ -135,7 +136,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
       unsigned CFIIndex = MMI.addFrameInst(
           MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset));
       BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex);
+          .addCFIIndex(CFIIndex)
+          .setMIFlags(MachineInstr::FrameSetup);
     }
     return;
   }
@@ -199,7 +201,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
     unsigned CFIIndex = MMI.addFrameInst(
         MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset));
     BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-        .addCFIIndex(CFIIndex);
+        .addCFIIndex(CFIIndex)
+        .setMIFlags(MachineInstr::FrameSetup);
   }
   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
          E = CSI.end(); I != E; ++I) {
@@ -226,7 +229,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
       unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
           nullptr, MRI->getDwarfRegNum(Reg, true), MFI->getObjectOffset(FI)));
       BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex);
+          .addCFIIndex(CFIIndex)
+          .setMIFlags(MachineInstr::FrameSetup);
       break;
     }
   }
@@ -244,13 +248,15 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
       unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfa(
           nullptr, MRI->getDwarfRegNum(FramePtr, true), CFAOffset));
       BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex);
+          .addCFIIndex(CFIIndex)
+          .setMIFlags(MachineInstr::FrameSetup);
     } else {
       unsigned CFIIndex =
           MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(
               nullptr, MRI->getDwarfRegNum(FramePtr, true)));
       BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex);
+          .addCFIIndex(CFIIndex)
+          .setMIFlags(MachineInstr::FrameSetup);
     }
     if (NumBytes > 508)
       // If offset is > 508 then sp cannot be adjusted in a single instruction,
@@ -267,7 +273,8 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
       unsigned CFIIndex = MMI.addFrameInst(
           MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset));
       BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
-          .addCFIIndex(CFIIndex);
+          .addCFIIndex(CFIIndex)
+          .setMIFlags(MachineInstr::FrameSetup);
     }
   }
 
diff --git a/llvm/test/DebugInfo/ARM/cfi-eof-prologue.ll b/llvm/test/DebugInfo/ARM/cfi-eof-prologue.ll
index 5f607ee..bbd93c9 100644
--- a/llvm/test/DebugInfo/ARM/cfi-eof-prologue.ll
+++ b/llvm/test/DebugInfo/ARM/cfi-eof-prologue.ll
@@ -14,7 +14,8 @@
 ; The location of the prologue_end marker should not be affected by the presence
 ; of CFI instructions.
 
-; RUN: llc -O0 -filetype=asm < %s | FileCheck %s
+; RUN: llc -O0 -filetype=asm -mtriple=thumbv7-apple-ios < %s | FileCheck %s
+; RUN: llc -O0 -filetype=asm -mtriple=thumbv6-apple-ios < %s | FileCheck %s
 
 ; ModuleID = 'test1.cpp'
 target datalayout = "e-m:o-p:32:32-f64:32:64-v64:32:64-v128:32:128-a:0:32-n32-S32"
-- 
2.7.4