[llvm] r174463 - Initial support for DWARF CFI parsing and dumping in LLVM
Matt Beaumont-Gay
matthewbg at google.com
Tue Feb 5 20:24:12 PST 2013
On Tue, Feb 5, 2013 at 3:30 PM, Eli Bendersky <eliben at google.com> wrote:
> Author: eliben
> Date: Tue Feb 5 17:30:58 2013
> New Revision: 174463
>
> URL: http://llvm.org/viewvc/llvm-project?rev=174463&view=rev
> Log:
> Initial support for DWARF CFI parsing and dumping in LLVM
>
> Added:
> llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
> llvm/trunk/lib/DebugInfo/DWARFDebugFrame.h
> Modified:
> llvm/trunk/include/llvm/DebugInfo/DIContext.h
> llvm/trunk/include/llvm/Support/Dwarf.h
> llvm/trunk/lib/DebugInfo/DWARFContext.cpp
> llvm/trunk/lib/DebugInfo/DWARFContext.h
> llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
>
> Modified: llvm/trunk/include/llvm/DebugInfo/DIContext.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/DebugInfo/DIContext.h?rev=174463&r1=174462&r2=174463&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/DebugInfo/DIContext.h (original)
> +++ llvm/trunk/include/llvm/DebugInfo/DIContext.h Tue Feb 5 17:30:58 2013
> @@ -101,6 +101,7 @@ enum DIDumpType {
> DIDT_Abbrev,
> DIDT_AbbrevDwo,
> DIDT_Aranges,
> + DIDT_Frames,
> DIDT_Info,
> DIDT_InfoDwo,
> DIDT_Line,
>
> Modified: llvm/trunk/include/llvm/Support/Dwarf.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Dwarf.h?rev=174463&r1=174462&r2=174463&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Support/Dwarf.h (original)
> +++ llvm/trunk/include/llvm/Support/Dwarf.h Tue Feb 5 17:30:58 2013
> @@ -16,6 +16,9 @@
> #ifndef LLVM_SUPPORT_DWARF_H
> #define LLVM_SUPPORT_DWARF_H
>
> +#include "llvm/Support/DataTypes.h"
> +
> +
> namespace llvm {
>
> //===----------------------------------------------------------------------===//
> @@ -53,10 +56,16 @@ enum llvm_dwarf_constants {
>
> DW_TAG_user_base = 0x1000, // Recommended base for user tags.
>
> - DW_CIE_VERSION = 1, // Common frame information version.
> - DW_CIE_ID = 0xffffffff // Common frame information mark.
> + DW_CIE_VERSION = 1 // Common frame information version.
> };
>
> +
> +// Special ID values that distinguish a CIE from a FDE in DWARF CFI.
> +// Not inside an enum because a 64-bit value is needed.
> +const uint32_t DW_CIE_ID = UINT32_MAX;
> +const uint64_t DW64_CIE_ID = UINT64_MAX;
> +
> +
> enum dwarf_constants {
> DWARF_VERSION = 2,
>
>
> Modified: llvm/trunk/lib/DebugInfo/DWARFContext.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFContext.cpp?rev=174463&r1=174462&r2=174463&view=diff
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARFContext.cpp (original)
> +++ llvm/trunk/lib/DebugInfo/DWARFContext.cpp Tue Feb 5 17:30:58 2013
> @@ -31,6 +31,11 @@ void DWARFContext::dump(raw_ostream &OS,
> getCompileUnitAtIndex(i)->dump(OS);
> }
>
> + if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
> + OS << "\n.debug_frame contents:\n";
> + getDebugFrame()->dump(OS);
> + }
> +
> uint32_t offset = 0;
> if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
> OS << "\n.debug_aranges contents:\n";
> @@ -152,6 +157,26 @@ const DWARFDebugAranges *DWARFContext::g
> return Aranges.get();
> }
>
> +const DWARFDebugFrame *DWARFContext::getDebugFrame() {
> + if (DebugFrame)
> + return DebugFrame.get();
> +
> + // There's a "bug" in the DWARFv3 standard with respect to the target address
> + // size within debug frame sections. While DWARF is supposed to be independent
> + // of its container, FDEs have fields with size being "target address size",
> + // which isn't specified in DWARF in general. It's only specified for CUs, but
> + // .eh_frame can appear without a .debug_info section. Follow the example of
> + // other tools (libdwarf) and extract this from the container (ObjectFile
> + // provides this information). This problem is fixed in DWARFv4
> + // See this dwarf-discuss discussion for more details:
> + // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
> + DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
> + getAddressSize());
> + DebugFrame.reset(new DWARFDebugFrame());
> + DebugFrame->parse(debugFrameData);
> + return DebugFrame.get();
> +}
> +
> const DWARFLineTable *
> DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
> if (!Line)
> @@ -440,7 +465,8 @@ DIInliningInfo DWARFContext::getInlining
> }
>
> DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj) :
> - IsLittleEndian(Obj->isLittleEndian()) {
> + IsLittleEndian(Obj->isLittleEndian()),
> + AddressSize(Obj->getBytesInAddress()) {
> error_code ec;
> for (object::section_iterator i = Obj->begin_sections(),
> e = Obj->end_sections();
> @@ -459,6 +485,8 @@ DWARFContextInMemory::DWARFContextInMemo
> LineSection = data;
> else if (name == "debug_aranges")
> ARangeSection = data;
> + else if (name == "debug_frame")
> + DebugFrameSection = data;
> else if (name == "debug_str")
> StringSection = data;
> else if (name == "debug_ranges") {
>
> Modified: llvm/trunk/lib/DebugInfo/DWARFContext.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFContext.h?rev=174463&r1=174462&r2=174463&view=diff
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARFContext.h (original)
> +++ llvm/trunk/lib/DebugInfo/DWARFContext.h Tue Feb 5 17:30:58 2013
> @@ -12,6 +12,7 @@
>
> #include "DWARFCompileUnit.h"
> #include "DWARFDebugAranges.h"
> +#include "DWARFDebugFrame.h"
> #include "DWARFDebugLine.h"
> #include "DWARFDebugRangeList.h"
> #include "llvm/ADT/OwningPtr.h"
> @@ -29,6 +30,7 @@ class DWARFContext : public DIContext {
> OwningPtr<DWARFDebugAbbrev> Abbrev;
> OwningPtr<DWARFDebugAranges> Aranges;
> OwningPtr<DWARFDebugLine> Line;
> + OwningPtr<DWARFDebugFrame> DebugFrame;
>
> SmallVector<DWARFCompileUnit, 1> DWOCUs;
> OwningPtr<DWARFDebugAbbrev> AbbrevDWO;
> @@ -84,6 +86,9 @@ public:
> /// Get a pointer to the parsed DebugAranges object.
> const DWARFDebugAranges *getDebugAranges();
>
> + /// Get a pointer to the parsed frame information object.
> + const DWARFDebugFrame *getDebugFrame();
> +
> /// Get a pointer to a parsed line table corresponding to a compile unit.
> const DWARFDebugLine::LineTable *
> getLineTableForCompileUnit(DWARFCompileUnit *cu);
> @@ -96,11 +101,13 @@ public:
> DILineInfoSpecifier Specifier = DILineInfoSpecifier());
>
> virtual bool isLittleEndian() const = 0;
> + virtual uint8_t getAddressSize() const = 0;
> virtual const RelocAddrMap &infoRelocMap() const = 0;
> virtual const RelocAddrMap &lineRelocMap() const = 0;
> virtual StringRef getInfoSection() = 0;
> virtual StringRef getAbbrevSection() = 0;
> virtual StringRef getARangeSection() = 0;
> + virtual StringRef getDebugFrameSection() = 0;
> virtual StringRef getLineSection() = 0;
> virtual StringRef getStringSection() = 0;
> virtual StringRef getRangeSection() = 0;
> @@ -132,11 +139,13 @@ private:
> class DWARFContextInMemory : public DWARFContext {
> virtual void anchor();
> bool IsLittleEndian;
> + uint8_t AddressSize;
> RelocAddrMap InfoRelocMap;
> RelocAddrMap LineRelocMap;
> StringRef InfoSection;
> StringRef AbbrevSection;
> StringRef ARangeSection;
> + StringRef DebugFrameSection;
> StringRef LineSection;
> StringRef StringSection;
> StringRef RangeSection;
> @@ -153,11 +162,13 @@ class DWARFContextInMemory : public DWAR
> public:
> DWARFContextInMemory(object::ObjectFile *);
> virtual bool isLittleEndian() const { return IsLittleEndian; }
> + virtual uint8_t getAddressSize() const { return AddressSize; }
> virtual const RelocAddrMap &infoRelocMap() const { return InfoRelocMap; }
> virtual const RelocAddrMap &lineRelocMap() const { return LineRelocMap; }
> virtual StringRef getInfoSection() { return InfoSection; }
> virtual StringRef getAbbrevSection() { return AbbrevSection; }
> virtual StringRef getARangeSection() { return ARangeSection; }
> + virtual StringRef getDebugFrameSection() { return DebugFrameSection; }
> virtual StringRef getLineSection() { return LineSection; }
> virtual StringRef getStringSection() { return StringSection; }
> virtual StringRef getRangeSection() { return RangeSection; }
>
> Added: llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp?rev=174463&view=auto
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp (added)
> +++ llvm/trunk/lib/DebugInfo/DWARFDebugFrame.cpp Tue Feb 5 17:30:58 2013
> @@ -0,0 +1,195 @@
> +//===-- DWARFDebugFrame.h - Parsing of .debug_frame -------------*- C++ -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#include "DWARFDebugFrame.h"
> +#include "llvm/ADT/SmallString.h"
> +#include "llvm/Support/DataTypes.h"
> +#include "llvm/Support/Dwarf.h"
> +#include "llvm/Support/Format.h"
> +
> +using namespace llvm;
> +using namespace dwarf;
> +
> +
> +class llvm::FrameEntry {
> +public:
> + enum FrameKind {FK_CIE, FK_FDE};
> + FrameEntry(FrameKind K, DataExtractor D, uint64_t Offset, uint64_t Length)
> + : Kind(K), Data(D), Offset(Offset), Length(Length)
> + {}
> +
> + FrameKind getKind() const { return Kind; }
> +
> + virtual void dumpHeader(raw_ostream &OS) const = 0;
> +protected:
> + const FrameKind Kind;
> + DataExtractor Data;
> + uint64_t Offset;
> + uint64_t Length;
> +};
> +
> +
> +class CIE : public FrameEntry {
What's a CIE? That is to say, it would probably be better if the name
were spelled out. (Likewise FDE below.)
> +public:
> + // CIEs (and FDEs) are simply container classes, so the only sensible way to
> + // create them is by providing the full parsed contents in the constructor.
> + CIE(DataExtractor D, uint64_t Offset, uint64_t Length, uint8_t Version,
> + SmallString<8> Augmentation, uint64_t CodeAlignmentFactor,
> + int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister)
> + : FrameEntry(FK_CIE, D, Offset, Length), Version(Version),
> + Augmentation(Augmentation), CodeAlignmentFactor(CodeAlignmentFactor),
> + DataAlignmentFactor(DataAlignmentFactor),
> + ReturnAddressRegister(ReturnAddressRegister)
> + {}
> +
> + void dumpHeader(raw_ostream &OS) const {
> + OS << format("%08x %08x %08x CIE", Offset, Length, DW_CIE_ID) << "\n";
> + OS << format(" Version: %d\n", Version);
> + OS << " Augmentation: \"" << Augmentation << "\"\n";
> + OS << format(" Code alignment factor: %u\n", CodeAlignmentFactor);
> + OS << format(" Data alignment factor: %d\n", DataAlignmentFactor);
> + OS << format(" Return address column: %d\n", ReturnAddressRegister);
> + OS << "\n";
> + }
> +
> + static bool classof(const FrameEntry *FE) {
> + return FE->getKind() == FK_CIE;
> + }
> +private:
> + uint8_t Version;
> + SmallString<8> Augmentation;
> + uint64_t CodeAlignmentFactor;
> + int64_t DataAlignmentFactor;
> + uint64_t ReturnAddressRegister;
> +};
> +
> +
> +class FDE : public FrameEntry {
> +public:
> + // Each FDE has a CIE it's "linked to". Our FDE contains is constructed with
> + // an offset to the CIE (provided by parsing the FDE header). The CIE itself
> + // is obtained lazily once it's actually required.
> + FDE(DataExtractor D, uint64_t Offset, uint64_t Length, int64_t LinkedCIEOffset,
> + uint64_t InitialLocation, uint64_t AddressRange)
> + : FrameEntry(FK_FDE, D, Offset, Length), LinkedCIEOffset(LinkedCIEOffset),
> + InitialLocation(InitialLocation), AddressRange(AddressRange),
> + LinkedCIE(NULL)
> + {}
> +
> + void dumpHeader(raw_ostream &OS) const {
> + OS << format("%08x %08x %08x FDE ", Offset, Length, LinkedCIEOffset);
> + OS << format("cie=%08x pc=%08x...%08x\n",
> + LinkedCIEOffset, InitialLocation,
> + InitialLocation + AddressRange);
> + OS << "\n";
> + }
> +
> + static bool classof(const FrameEntry *FE) {
> + return FE->getKind() == FK_FDE;
> + }
> +private:
> + uint64_t LinkedCIEOffset;
> + uint64_t InitialLocation;
> + uint64_t AddressRange;
> + CIE *LinkedCIE;
> +};
> +
> +
> +DWARFDebugFrame::DWARFDebugFrame()
> +{
> +}
> +
> +
> +DWARFDebugFrame::~DWARFDebugFrame()
> +{
> + for (EntryVector::iterator I = Entries.begin(), E = Entries.end();
> + I != E; ++I) {
> + delete *I;
> + }
> +}
> +
> +
> +static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
> + uint32_t Offset, int Length) {
> + errs() << "DUMP: ";
> + for (int i = 0; i < Length; ++i) {
> + uint8_t c = Data.getU8(&Offset);
> + errs().write_hex(c); errs() << " ";
> + }
> + errs() << "\n";
> +}
> +
> +
> +void DWARFDebugFrame::parse(DataExtractor Data) {
> + uint32_t Offset = 0;
> +
> + while (Data.isValidOffset(Offset)) {
> + uint32_t StartOffset = Offset;
> +
> + bool IsDWARF64 = false;
> + uint64_t Length = Data.getU32(&Offset);
> + uint64_t Id;
> +
> + if (Length == UINT32_MAX) {
> + // DWARF-64 is distinguished by the first 32 bits of the initial length
> + // field being 0xffffffff. Then, the next 64 bits are the actual entry
> + // length.
> + IsDWARF64 = true;
> + Length = Data.getU64(&Offset);
> + }
> +
> + // At this point, Offset points to the next field after Length.
> + // Length is the structure size excluding itself. Compute an offset one
> + // past the end of the structure (needed to know how many instructions to
> + // read).
> + // TODO: For honest DWARF64 support, DataExtractor will have to treat
> + // offset_ptr as uint64_t*
> + uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);
> +
> + // The Id field's size depends on the DWARF format
> + Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
> + bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);
> +
> + if (IsCIE) {
> + // Note: this is specifically DWARFv3 CIE header structure. It was
> + // changed in DWARFv4.
> + uint8_t Version = Data.getU8(&Offset);
> + const char *Augmentation = Data.getCStr(&Offset);
> + uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
> + int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
> + uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);
> +
> + CIE *NewCIE = new CIE(Data, StartOffset, Length, Version,
> + StringRef(Augmentation), CodeAlignmentFactor,
> + DataAlignmentFactor, ReturnAddressRegister);
> + Entries.push_back(NewCIE);
> + } else {
> + // FDE
> + uint64_t CIEPointer = Id;
> + uint64_t InitialLocation = Data.getAddress(&Offset);
> + uint64_t AddressRange = Data.getAddress(&Offset);
> +
> + FDE *NewFDE = new FDE(Data, StartOffset, Length, CIEPointer,
> + InitialLocation, AddressRange);
> + Entries.push_back(NewFDE);
> + }
> +
> + Offset = EndStructureOffset;
> + }
> +}
> +
> +
> +void DWARFDebugFrame::dump(raw_ostream &OS) const {
> + OS << "\n";
> + for (EntryVector::const_iterator I = Entries.begin(), E = Entries.end();
> + I != E; ++I) {
> + (*I)->dumpHeader(OS);
> + }
> +}
> +
>
> Added: llvm/trunk/lib/DebugInfo/DWARFDebugFrame.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFDebugFrame.h?rev=174463&view=auto
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARFDebugFrame.h (added)
> +++ llvm/trunk/lib/DebugInfo/DWARFDebugFrame.h Tue Feb 5 17:30:58 2013
> @@ -0,0 +1,46 @@
> +//===-- DWARFDebugFrame.h - Parsing of .debug_frame -------------*- C++ -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#ifndef LLVM_DEBUGINFO_DWARFDEBUGFRAME_H
> +#define LLVM_DEBUGINFO_DWARFDEBUGFRAME_H
> +
> +#include "llvm/Support/DataExtractor.h"
> +#include "llvm/Support/raw_ostream.h"
> +#include <vector>
> +
> +
> +namespace llvm {
> +
> +class FrameEntry;
> +
> +
> +/// \brief A parsed .debug_frame section
> +///
> +class DWARFDebugFrame {
> +public:
> + DWARFDebugFrame();
> + ~DWARFDebugFrame();
> +
> + /// \brief Dump the section data into the given stream.
> + void dump(raw_ostream &OS) const;
> +
> + /// \brief Parse the section from raw data.
> + /// data is assumed to be pointing to the beginning of the section.
> + void parse(DataExtractor Data);
> +
> +private:
> + typedef std::vector<FrameEntry *> EntryVector;
> + EntryVector Entries;
> +};
> +
> +
> +} // namespace llvm
> +
> +#endif
> +
>
> Modified: llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp?rev=174463&r1=174462&r2=174463&view=diff
> ==============================================================================
> --- llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp (original)
> +++ llvm/trunk/tools/llvm-dwarfdump/llvm-dwarfdump.cpp Tue Feb 5 17:30:58 2013
> @@ -63,6 +63,7 @@ DumpType("debug-dump", cl::init(DIDT_All
> clEnumValN(DIDT_Info, "info", ".debug_info"),
> clEnumValN(DIDT_InfoDwo, "info.dwo", ".debug_info.dwo"),
> clEnumValN(DIDT_Line, "line", ".debug_line"),
> + clEnumValN(DIDT_Frames, "frames", ".debug_frame"),
> clEnumValN(DIDT_Ranges, "ranges", ".debug_ranges"),
> clEnumValN(DIDT_Str, "str", ".debug_str"),
> clEnumValN(DIDT_StrDwo, "str.dwo", ".debug_str.dwo"),
>
>
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