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| author | Oliver Stannard <oliver.stannard@arm.com> | 2014-06-19 15:39:33 +0000 |
|---|---|---|
| committer | Oliver Stannard <oliver.stannard@arm.com> | 2014-06-19 15:39:33 +0000 |
| commit | bb804ee909a0e81d39920bdc8272e624fb8da443 (patch) | |
| tree | cc16de26c417b293df926f1459e185d0cd405aa3 /lib/MC | |
| parent | 7e4098332804df5126060a2c8f846445a82c5a62 (diff) | |
| download | llvm-bb804ee909a0e81d39920bdc8272e624fb8da443.tar.gz llvm-bb804ee909a0e81d39920bdc8272e624fb8da443.tar.bz2 llvm-bb804ee909a0e81d39920bdc8272e624fb8da443.tar.xz | |
Emit DWARF3 call frame information when DWARF3+ debug info is requested
Currently, llvm always emits a DWARF CIE with a version of 1, even when emitting
DWARF 3 or 4, which both support CIE version 3. This patch makes it emit the
newer CIE version when we are emitting DWARF 3 or 4. This will not reduce
compatibility, as we already emit other DWARF3/4 features, and is worth doing as
the DWARF3 spec removed some ambiguities in the interpretation of call frame
information.
It also fixes a minor bug where the "return address" field of the CIE was
encoded as a ULEB128, which is only valid when the CIE version is 3. There are
no test changes for this, because (as far as I can tell) none of the platforms
that we test have a return address register with a DWARF register number >127.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211272 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/MC')
| -rw-r--r-- | lib/MC/MCDwarf.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/MC/MCDwarf.cpp b/lib/MC/MCDwarf.cpp index be6731abed..1016466839 100644 --- a/lib/MC/MCDwarf.cpp +++ b/lib/MC/MCDwarf.cpp @@ -1270,7 +1270,10 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer, // Version if (verboseAsm) streamer.AddComment("DW_CIE_VERSION"); - streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1); + // For DWARF2, we use CIE version 1 + // For DWARF3+, we use CIE version 3 + uint8_t CIEVersion = context.getDwarfVersion() <= 2 ? 1 : 3; + streamer.EmitIntValue(CIEVersion, 1); // Augmentation String SmallString<8> Augmentation; @@ -1298,7 +1301,14 @@ const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer, // Return Address Register if (verboseAsm) streamer.AddComment("CIE Return Address Column"); - streamer.EmitULEB128IntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true)); + if (CIEVersion == 1) { + assert(MRI->getRARegister() <= 255 && + "DWARF 2 encodes return_address_register in one byte"); + streamer.EmitIntValue(MRI->getDwarfRegNum(MRI->getRARegister(), true), 1); + } else { + streamer.EmitULEB128IntValue( + MRI->getDwarfRegNum(MRI->getRARegister(), true)); + } // Augmentation Data Length (optional) |