From 66aefa805b0c0be252bf092816464eec566b713b Mon Sep 17 00:00:00 2001 From: Mark Seaborn Date: Mon, 27 Jan 2014 22:38:14 +0000 Subject: [PATCH] ARM MC: Fix the initial DWARF CFI unwind info at the start of a function This brings MC into line with GNU 'as' on ARM, and it brings the ARM target into line with most other LLVM targets, which declare the initial CFI state with addInitialFrameState(). Without this, functions generated with .cfi_startproc/endproc on ARM will tend to cause GDB to abort with: gdb/dwarf2-frame.c:1132: internal-error: Unknown CFA rule. I've also tested this by comparing the output of "readelf -w" on the object files produced by llvm-mc and gas when given the .s file added here. This change is part of addressing PR18636. Differential Revision: http://llvm-reviews.chandlerc.com/D2597 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200255 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp | 10 ++++++++-- test/MC/ARM/dwarf-cfi-initial-state.s | 16 ++++++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) create mode 100644 test/MC/ARM/dwarf-cfi-initial-state.s diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp index 2d7c25f31d8..4581f411304 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp @@ -212,10 +212,16 @@ static MCRegisterInfo *createARMMCRegisterInfo(StringRef Triple) { static MCAsmInfo *createARMMCAsmInfo(const MCRegisterInfo &MRI, StringRef TT) { Triple TheTriple(TT); + MCAsmInfo *MAI; if (TheTriple.isOSBinFormatMachO()) - return new ARMMCAsmInfoDarwin(); + MAI = new ARMMCAsmInfoDarwin(); + else + MAI = new ARMELFMCAsmInfo(); - return new ARMELFMCAsmInfo(); + unsigned Reg = MRI.getDwarfRegNum(ARM::SP, true); + MAI->addInitialFrameState(MCCFIInstruction::createDefCfa(0, Reg, 0)); + + return MAI; } static MCCodeGenInfo *createARMMCCodeGenInfo(StringRef TT, Reloc::Model RM, diff --git a/test/MC/ARM/dwarf-cfi-initial-state.s b/test/MC/ARM/dwarf-cfi-initial-state.s new file mode 100644 index 00000000000..2d638e9c4b2 --- /dev/null +++ b/test/MC/ARM/dwarf-cfi-initial-state.s @@ -0,0 +1,16 @@ +# RUN: llvm-mc < %s -triple=armv7-linux-gnueabi -filetype=obj -o - \ +# RUN: | llvm-dwarfdump - | FileCheck %s + +.cfi_sections .debug_frame +.cfi_startproc +bx lr +.cfi_endproc + +# CHECK: .debug_frame contents: +# CHECK: CIE +# CHECK-NOT: DW_CFA +# When llvm-dwarfdump prints the full info for the DW_CFA_def_cfa +# field, we can check that here too. +# CHECK: DW_CFA_def_cfa: +# CHECK-NOT: DW_CFA +# CHECK: FDE -- 2.11.0