From bb804ee909a0e81d39920bdc8272e624fb8da443 Mon Sep 17 00:00:00 2001 From: Oliver Stannard Date: Thu, 19 Jun 2014 15:39:33 +0000 Subject: 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 --- lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 2 ++ lib/MC/MCDwarf.cpp | 14 ++++++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 7aaf731b6f..3847eb124f 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -209,6 +209,8 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M) DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber : MMI->getModule()->getDwarfVersion(); + Asm->OutStreamer.getContext().setDwarfVersion(DwarfVersion); + { NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); beginModule(); 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) -- cgit v1.2.3