Eric Christopher
2012-Nov-06 01:17 UTC
[LLVMdev] [PATCH] basic reading reloc visitor for x86_64 ELF
For llvm-dwarfdump we need to handle relocations inside the debug info
sections in order to successfully dump the dwarf info including strings.
Nick sent out a partial patch that did this not too long ago and I've taken
it and gone in a bit of a different direction, but kept the same basic
architecture.
In place of applying the relocations to the data we've read from disk
I'm
keeping a separate mapping table to the side and checking that at locations
in the dwarf I'm expecting relocated values. This adds a bit of complexity
to the dwarf parsing/extraction at the benefit of not allocating memory for
the entire size of the debug info section.
Couple of areas that will need to be improved later:
a) Relocations in more than a single section: the .debug_info section is
the primary one I cared about first, however, we'll need either
1) A better mapping that contains section + address (since the debug
sections are mapped at address 0 I can't just use total offset)
2) More mappings per section we're disassembling
I'm likely to go with #2 rather than #1, but I'm open to any rationale
either direction.
b) Symbol relocations for function sections and/or functions as well as
hooking it into, e.g. the aranges disassembly.
I've got plans to add these things as I go along, but since it was now
pretty usable for testing/dumping I wanted to get it in and then
incremental on top of it.
Thoughts?
-eric
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diff --git a/include/llvm/DebugInfo/DIContext.h
b/include/llvm/DebugInfo/DIContext.h
index 8d6054a..e6fa54d 100644
--- a/include/llvm/DebugInfo/DIContext.h
+++ b/include/llvm/DebugInfo/DIContext.h
@@ -15,6 +15,7 @@
#ifndef LLVM_DEBUGINFO_DICONTEXT_H
#define LLVM_DEBUGINFO_DICONTEXT_H
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
@@ -89,6 +90,8 @@ public:
}
};
+typedef DenseMap<uint64_t, std::pair<uint8_t, int64_t> >
RelocAddrMap;
+
class DIContext {
public:
virtual ~DIContext();
@@ -100,7 +103,8 @@ public:
StringRef aRangeSection = StringRef(),
StringRef lineSection = StringRef(),
StringRef stringSection = StringRef(),
- StringRef rangeSection = StringRef());
+ StringRef rangeSection = StringRef(),
+ const RelocAddrMap &Map =
RelocAddrMap());
virtual void dump(raw_ostream &OS) = 0;
diff --git a/include/llvm/Support/DataExtractor.h
b/include/llvm/Support/DataExtractor.h
index 8d880fd..a3ae782 100644
--- a/include/llvm/Support/DataExtractor.h
+++ b/include/llvm/Support/DataExtractor.h
@@ -10,6 +10,7 @@
#ifndef LLVM_SUPPORT_DATAEXTRACTOR_H
#define LLVM_SUPPORT_DATAEXTRACTOR_H
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
diff --git a/lib/DebugInfo/DIContext.cpp b/lib/DebugInfo/DIContext.cpp
index ead57f9..691a92c 100644
--- a/lib/DebugInfo/DIContext.cpp
+++ b/lib/DebugInfo/DIContext.cpp
@@ -19,8 +19,9 @@ DIContext *DIContext::getDWARFContext(bool isLittleEndian,
StringRef aRangeSection,
StringRef lineSection,
StringRef stringSection,
- StringRef rangeSection) {
+ StringRef rangeSection,
+ const RelocAddrMap &Map) {
return new DWARFContextInMemory(isLittleEndian, infoSection, abbrevSection,
aRangeSection, lineSection, stringSection,
- rangeSection);
+ rangeSection, Map);
}
diff --git a/lib/DebugInfo/DWARFContext.h b/lib/DebugInfo/DWARFContext.h
index d10e850..4001792 100644
--- a/lib/DebugInfo/DWARFContext.h
+++ b/lib/DebugInfo/DWARFContext.h
@@ -26,6 +26,7 @@ namespace llvm {
/// methods that a concrete implementation provides.
class DWARFContext : public DIContext {
bool IsLittleEndian;
+ const RelocAddrMap &RelocMap;
SmallVector<DWARFCompileUnit, 1> CUs;
OwningPtr<DWARFDebugAbbrev> Abbrev;
@@ -38,9 +39,11 @@ class DWARFContext : public DIContext {
/// Read compile units from the debug_info section and store them in CUs.
void parseCompileUnits();
protected:
- DWARFContext(bool isLittleEndian) : IsLittleEndian(isLittleEndian) {}
+ DWARFContext(bool isLittleEndian, const RelocAddrMap &Map) :
+ IsLittleEndian(isLittleEndian), RelocMap(Map) {}
public:
virtual void dump(raw_ostream &OS);
+
/// Get the number of compile units in this context.
unsigned getNumCompileUnits() {
if (CUs.empty())
@@ -70,6 +73,7 @@ public:
DILineInfoSpecifier Specifier = DILineInfoSpecifier());
bool isLittleEndian() const { return IsLittleEndian; }
+ const RelocAddrMap &relocMap() const { return RelocMap; }
virtual StringRef getInfoSection() = 0;
virtual StringRef getAbbrevSection() = 0;
@@ -108,8 +112,9 @@ public:
StringRef aRangeSection,
StringRef lineSection,
StringRef stringSection,
- StringRef rangeSection)
- : DWARFContext(isLittleEndian),
+ StringRef rangeSection,
+ const RelocAddrMap &Map = RelocAddrMap())
+ : DWARFContext(isLittleEndian, Map),
InfoSection(infoSection),
AbbrevSection(abbrevSection),
ARangeSection(aRangeSection),
diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp
index c9ecbbb..fea9fd7 100644
--- a/lib/DebugInfo/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARFFormValue.cpp
@@ -10,6 +10,7 @@
#include "DWARFFormValue.h"
#include "DWARFCompileUnit.h"
#include "DWARFContext.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
@@ -98,8 +99,16 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t
*offset_ptr,
indirect = false;
switch (Form) {
case DW_FORM_addr:
- case DW_FORM_ref_addr:
- Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize());
+ case DW_FORM_ref_addr: {
+ RelocAddrMap::const_iterator AI
+ = cu->getContext().relocMap().find(*offset_ptr);
+ if (AI != cu->getContext().relocMap().end()) {
+ const std::pair<uint8_t, int64_t> &R = AI->second;
+ Value.uval = R.second;
+ *offset_ptr += R.first;
+ } else
+ Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize());
+ }
break;
case DW_FORM_exprloc:
case DW_FORM_block:
@@ -138,9 +147,17 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t
*offset_ptr,
case DW_FORM_sdata:
Value.sval = data.getSLEB128(offset_ptr);
break;
- case DW_FORM_strp:
- Value.uval = data.getU32(offset_ptr);
+ case DW_FORM_strp: {
+ RelocAddrMap::const_iterator AI
+ = cu->getContext().relocMap().find(*offset_ptr);
+ if (AI != cu->getContext().relocMap().end()) {
+ const std::pair<uint8_t, int64_t> &R = AI->second;
+ Value.uval = R.second;
+ *offset_ptr += R.first;
+ } else
+ Value.uval = data.getU32(offset_ptr);
break;
+ }
case DW_FORM_udata:
case DW_FORM_ref_udata:
Value.uval = data.getULEB128(offset_ptr);
diff --git a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
index 309bc4e..e73300a 100644
--- a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -15,6 +15,7 @@
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Object/ObjectFile.h"
+#include "llvm/Object/RelocVisitor.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
@@ -28,6 +29,9 @@
#include "llvm/Support/system_error.h"
#include <algorithm>
#include <cstring>
+#include <list>
+#include <string>
+
using namespace llvm;
using namespace object;
@@ -67,6 +71,7 @@ static void DumpInput(const StringRef &Filename) {
OwningPtr<ObjectFile> Obj(ObjectFile::createObjectFile(Buff.take()));
StringRef DebugInfoSection;
+ RelocAddrMap RelocMap;
StringRef DebugAbbrevSection;
StringRef DebugLineSection;
StringRef DebugArangesSection;
@@ -97,6 +102,57 @@ static void DumpInput(const StringRef &Filename) {
DebugStringSection = data;
else if (name == "debug_ranges")
DebugRangesSection = data;
+ // Any more debug info sections go here.
+ else
+ continue;
+
+ // TODO: For now only handle relocations for the debug_info section.
+ if (name != "debug_info")
+ continue;
+
+ if (i->begin_relocations() != i->end_relocations()) {
+ uint64_t SectionSize;
+ i->getSize(SectionSize);
+ for (relocation_iterator reloc_i = i->begin_relocations(),
+ reloc_e = i->end_relocations();
+ reloc_i != reloc_e; reloc_i.increment(ec)) {
+ uint64_t Address;
+ reloc_i->getAddress(Address);
+ uint64_t Type;
+ reloc_i->getType(Type);
+
+ RelocVisitor V(Obj->getFileFormatName());
+ // The section address is always 0 for debug sections.
+ RelocToApply R(V.visit(Type, *reloc_i));
+ if (V.error()) {
+ SmallString<32> Name;
+ error_code ec(reloc_i->getTypeName(Name));
+ if (ec) {
+ errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n";
+ }
+ errs() << "error: failed to compute relocation: "
+ << Name << "\n";
+ continue;
+ }
+
+ if (Address + R.Width > SectionSize) {
+ errs() << "error: " << R.Width <<
"-byte relocation starting "
+ << Address << " bytes into section "
<< name << " which is "
+ << SectionSize << " bytes long.\n";
+ continue;
+ }
+ if (R.Width > 8) {
+ errs() << "error: can't handle a relocation of more
than 8 bytes at "
+ "a time.\n";
+ continue;
+ }
+ DEBUG(dbgs() << "Writing " <<
format("%p", R.Value)
+ << " at " << format("%p",
Address)
+ << " with width " <<
format("%d", R.Width)
+ << "\n");
+ RelocMap[Address] = std::make_pair(R.Width, R.Value);
+ }
+ }
}
OwningPtr<DIContext> dictx(DIContext::getDWARFContext(/*FIXME*/true,
@@ -105,7 +161,8 @@ static void DumpInput(const StringRef &Filename) {
DebugArangesSection,
DebugLineSection,
DebugStringSection,
- DebugRangesSection));
+ DebugRangesSection,
+ RelocMap));
if (Address == -1ULL) {
outs() << Filename
<< ":\tfile format " <<
Obj->getFileFormatName() << "\n\n";
Michael Spencer
2012-Nov-06 08:00 UTC
[LLVMdev] [PATCH] basic reading reloc visitor for x86_64 ELF
On Mon, Nov 5, 2012 at 5:17 PM, Eric Christopher <echristo at gmail.com> wrote:> For llvm-dwarfdump we need to handle relocations inside the debug info > sections in order to successfully dump the dwarf info including strings. > Nick sent out a partial patch that did this not too long ago and I've taken > it and gone in a bit of a different direction, but kept the same basic > architecture. > > In place of applying the relocations to the data we've read from disk I'm > keeping a separate mapping table to the side and checking that at locations > in the dwarf I'm expecting relocated values. This adds a bit of complexity > to the dwarf parsing/extraction at the benefit of not allocating memory for > the entire size of the debug info section. > > Couple of areas that will need to be improved later: > > a) Relocations in more than a single section: the .debug_info section is the > primary one I cared about first, however, we'll need either > 1) A better mapping that contains section + address (since the debug > sections are mapped at address 0 I can't just use total offset) > 2) More mappings per section we're disassembling > > I'm likely to go with #2 rather than #1, but I'm open to any rationale > either direction. > > b) Symbol relocations for function sections and/or functions as well as > hooking it into, e.g. the aranges disassembly. > > I've got plans to add these things as I go along, but since it was now > pretty usable for testing/dumping I wanted to get it in and then incremental > on top of it. > > Thoughts? > > -eric > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >This seems to be missing RelocVisitor.h - Michael Spencer
Eric Christopher
2012-Nov-06 16:38 UTC
[LLVMdev] [PATCH] basic reading reloc visitor for x86_64 ELF
That's what I get for moving the patch between machines. Attached here along with one of the comments that Eli wanted. -eric On Tue, Nov 6, 2012 at 12:00 AM, Michael Spencer <bigcheesegs at gmail.com>wrote:> On Mon, Nov 5, 2012 at 5:17 PM, Eric Christopher <echristo at gmail.com> > wrote: > > For llvm-dwarfdump we need to handle relocations inside the debug info > > sections in order to successfully dump the dwarf info including strings. > > Nick sent out a partial patch that did this not too long ago and I've > taken > > it and gone in a bit of a different direction, but kept the same basic > > architecture. > > > > In place of applying the relocations to the data we've read from disk I'm > > keeping a separate mapping table to the side and checking that at > locations > > in the dwarf I'm expecting relocated values. This adds a bit of > complexity > > to the dwarf parsing/extraction at the benefit of not allocating memory > for > > the entire size of the debug info section. > > > > Couple of areas that will need to be improved later: > > > > a) Relocations in more than a single section: the .debug_info section is > the > > primary one I cared about first, however, we'll need either > > 1) A better mapping that contains section + address (since the debug > > sections are mapped at address 0 I can't just use total offset) > > 2) More mappings per section we're disassembling > > > > I'm likely to go with #2 rather than #1, but I'm open to any rationale > > either direction. > > > > b) Symbol relocations for function sections and/or functions as well as > > hooking it into, e.g. the aranges disassembly. > > > > I've got plans to add these things as I go along, but since it was now > > pretty usable for testing/dumping I wanted to get it in and then > incremental > > on top of it. > > > > Thoughts? > > > > -eric > > > > _______________________________________________ > > LLVM Developers mailing list > > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > > > This seems to be missing RelocVisitor.h > > - Michael Spencer >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20121106/77a0f946/attachment.html> -------------- next part -------------- commit a35a9c732fd8838523561698bf63b9c17758983e Author: Eric Christopher <echristo at gmail.com> Date: Tue Nov 6 08:37:24 2012 -0800 First stab at relocation visitor for object. diff --git a/include/llvm/DebugInfo/DIContext.h b/include/llvm/DebugInfo/DIContext.h index 8d6054a..2e34bac 100644 --- a/include/llvm/DebugInfo/DIContext.h +++ b/include/llvm/DebugInfo/DIContext.h @@ -15,6 +15,7 @@ #ifndef LLVM_DEBUGINFO_DICONTEXT_H #define LLVM_DEBUGINFO_DICONTEXT_H +#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringRef.h" @@ -89,6 +90,13 @@ public: } }; +// In place of applying the relocations to the data we've read from disk we use +// a separate mapping table to the side and checking that at locations in the dwarf +// we expec relocated values. This adds a bit of complexity to the dwarf +// parsing/extraction at the benefit of not allocating memory for the entire +// size of the debug info sections. +typedef DenseMap<uint64_t, std::pair<uint8_t, int64_t> > RelocAddrMap; + class DIContext { public: virtual ~DIContext(); @@ -100,7 +108,8 @@ public: StringRef aRangeSection = StringRef(), StringRef lineSection = StringRef(), StringRef stringSection = StringRef(), - StringRef rangeSection = StringRef()); + StringRef rangeSection = StringRef(), + const RelocAddrMap &Map = RelocAddrMap()); virtual void dump(raw_ostream &OS) = 0; diff --git a/include/llvm/Object/RelocVisitor.h b/include/llvm/Object/RelocVisitor.h new file mode 100644 index 0000000..7668bde --- /dev/null +++ b/include/llvm/Object/RelocVisitor.h @@ -0,0 +1,131 @@ +//===-- RelocVisitor.h - Visitor for object file relocations -*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file provides a wrapper around all the different types of relocations +// in different file formats, such that a client can handle them in a unified +// manner by only implementing a minimal number of functions. +// +//===----------------------------------------------------------------------===// + +#ifndef _LLVM_OBJECT_RELOCVISITOR +#define _LLVM_OBJECT_RELOCVISITOR + +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Object/ObjectFile.h" +#include "llvm/Object/ELF.h" +#include "llvm/ADT/StringRef.h" + +namespace llvm { +namespace object { + +struct RelocToApply { + // The computed value after applying the relevant relocations. + int64_t Value; + + // The width of the value; how many bytes to touch when applying the + // relocation. + char Width; + RelocToApply(const RelocToApply &In) : Value(In.Value), Width(In.Width) {} + RelocToApply(int64_t Value, char Width) : Value(Value), Width(Width) {} + RelocToApply() : Value(0), Width(0) {} +}; + +/// @brief Base class for object file relocation visitors. +class RelocVisitor { +public: + explicit RelocVisitor(llvm::StringRef FileFormat) + : FileFormat(FileFormat), HasError(false) {} + + // TODO: Should handle multiple applied relocations via either passing in the + // previously computed value or just count paired relocations as a single + // visit. + RelocToApply visit(uint32_t RelocType, RelocationRef R, uint64_t SecAddr = 0, + uint64_t Value = 0) { + if (FileFormat == "ELF64-x86-64") { + switch (RelocType) { + case llvm::ELF::R_X86_64_NONE: + return visitELF_X86_64_NONE(R); + case llvm::ELF::R_X86_64_64: + return visitELF_X86_64_64(R, Value); + case llvm::ELF::R_X86_64_PC32: + return visitELF_X86_64_PC32(R, Value, SecAddr); + case llvm::ELF::R_X86_64_32: + return visitELF_X86_64_32(R, Value); + case llvm::ELF::R_X86_64_32S: + return visitELF_X86_64_32S(R, Value); + default: + HasError = true; + return RelocToApply(); + } + } + return RelocToApply(); + } + + bool error() { return HasError; } + +private: + llvm::StringRef FileFormat; + bool HasError; + + /// Operations + + // Width is the width in bytes of the extend. + RelocToApply zeroExtend(RelocToApply r, char Width) { + if (Width == r.Width) + return r; + r.Value &= (1 << ((Width * 8))) - 1; + return r; + } + RelocToApply signExtend(RelocToApply r, char Width) { + if (Width == r.Width) + return r; + bool SignBit = r.Value & (1 << ((Width * 8) - 1)); + if (SignBit) { + r.Value |= ~((1 << (Width * 8)) - 1); + } else { + r.Value &= (1 << (Width * 8)) - 1; + } + return r; + } + + /// X86-64 ELF + RelocToApply visitELF_X86_64_NONE(RelocationRef R) { + return RelocToApply(0, 0); + } + RelocToApply visitELF_X86_64_64(RelocationRef R, uint64_t Value) { + int64_t Addend; + R.getAdditionalInfo(Addend); + return RelocToApply(Value + Addend, 8); + } + RelocToApply visitELF_X86_64_PC32(RelocationRef R, uint64_t Value, + uint64_t SecAddr) { + int64_t Addend; + R.getAdditionalInfo(Addend); + uint64_t Address; + R.getAddress(Address); + return RelocToApply(Value + Addend - Address, 4); + } + RelocToApply visitELF_X86_64_32(RelocationRef R, uint64_t Value) { + int64_t Addend; + R.getAdditionalInfo(Addend); + uint32_t Res = (Value + Addend) & 0xFFFFFFFF; + return RelocToApply(Res, 4); + } + RelocToApply visitELF_X86_64_32S(RelocationRef R, uint64_t Value) { + int64_t Addend; + R.getAdditionalInfo(Addend); + int32_t Res = (Value + Addend) & 0xFFFFFFFF; + return RelocToApply(Res, 4); + } +}; + +} +} +#endif diff --git a/include/llvm/Support/DataExtractor.h b/include/llvm/Support/DataExtractor.h index 8d880fd..a3ae782 100644 --- a/include/llvm/Support/DataExtractor.h +++ b/include/llvm/Support/DataExtractor.h @@ -10,6 +10,7 @@ #ifndef LLVM_SUPPORT_DATAEXTRACTOR_H #define LLVM_SUPPORT_DATAEXTRACTOR_H +#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/StringRef.h" #include "llvm/Support/DataTypes.h" diff --git a/lib/DebugInfo/DIContext.cpp b/lib/DebugInfo/DIContext.cpp index ead57f9..691a92c 100644 --- a/lib/DebugInfo/DIContext.cpp +++ b/lib/DebugInfo/DIContext.cpp @@ -19,8 +19,9 @@ DIContext *DIContext::getDWARFContext(bool isLittleEndian, StringRef aRangeSection, StringRef lineSection, StringRef stringSection, - StringRef rangeSection) { + StringRef rangeSection, + const RelocAddrMap &Map) { return new DWARFContextInMemory(isLittleEndian, infoSection, abbrevSection, aRangeSection, lineSection, stringSection, - rangeSection); + rangeSection, Map); } diff --git a/lib/DebugInfo/DWARFContext.h b/lib/DebugInfo/DWARFContext.h index d10e850..4001792 100644 --- a/lib/DebugInfo/DWARFContext.h +++ b/lib/DebugInfo/DWARFContext.h @@ -26,6 +26,7 @@ namespace llvm { /// methods that a concrete implementation provides. class DWARFContext : public DIContext { bool IsLittleEndian; + const RelocAddrMap &RelocMap; SmallVector<DWARFCompileUnit, 1> CUs; OwningPtr<DWARFDebugAbbrev> Abbrev; @@ -38,9 +39,11 @@ class DWARFContext : public DIContext { /// Read compile units from the debug_info section and store them in CUs. void parseCompileUnits(); protected: - DWARFContext(bool isLittleEndian) : IsLittleEndian(isLittleEndian) {} + DWARFContext(bool isLittleEndian, const RelocAddrMap &Map) : + IsLittleEndian(isLittleEndian), RelocMap(Map) {} public: virtual void dump(raw_ostream &OS); + /// Get the number of compile units in this context. unsigned getNumCompileUnits() { if (CUs.empty()) @@ -70,6 +73,7 @@ public: DILineInfoSpecifier Specifier = DILineInfoSpecifier()); bool isLittleEndian() const { return IsLittleEndian; } + const RelocAddrMap &relocMap() const { return RelocMap; } virtual StringRef getInfoSection() = 0; virtual StringRef getAbbrevSection() = 0; @@ -108,8 +112,9 @@ public: StringRef aRangeSection, StringRef lineSection, StringRef stringSection, - StringRef rangeSection) - : DWARFContext(isLittleEndian), + StringRef rangeSection, + const RelocAddrMap &Map = RelocAddrMap()) + : DWARFContext(isLittleEndian, Map), InfoSection(infoSection), AbbrevSection(abbrevSection), ARangeSection(aRangeSection), diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp index c9ecbbb..fea9fd7 100644 --- a/lib/DebugInfo/DWARFFormValue.cpp +++ b/lib/DebugInfo/DWARFFormValue.cpp @@ -10,6 +10,7 @@ #include "DWARFFormValue.h" #include "DWARFCompileUnit.h" #include "DWARFContext.h" +#include "llvm/Support/Debug.h" #include "llvm/Support/Dwarf.h" #include "llvm/Support/Format.h" #include "llvm/Support/raw_ostream.h" @@ -98,8 +99,16 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr, indirect = false; switch (Form) { case DW_FORM_addr: - case DW_FORM_ref_addr: - Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize()); + case DW_FORM_ref_addr: { + RelocAddrMap::const_iterator AI + = cu->getContext().relocMap().find(*offset_ptr); + if (AI != cu->getContext().relocMap().end()) { + const std::pair<uint8_t, int64_t> &R = AI->second; + Value.uval = R.second; + *offset_ptr += R.first; + } else + Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize()); + } break; case DW_FORM_exprloc: case DW_FORM_block: @@ -138,9 +147,17 @@ DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr, case DW_FORM_sdata: Value.sval = data.getSLEB128(offset_ptr); break; - case DW_FORM_strp: - Value.uval = data.getU32(offset_ptr); + case DW_FORM_strp: { + RelocAddrMap::const_iterator AI + = cu->getContext().relocMap().find(*offset_ptr); + if (AI != cu->getContext().relocMap().end()) { + const std::pair<uint8_t, int64_t> &R = AI->second; + Value.uval = R.second; + *offset_ptr += R.first; + } else + Value.uval = data.getU32(offset_ptr); break; + } case DW_FORM_udata: case DW_FORM_ref_udata: Value.uval = data.getULEB128(offset_ptr); diff --git a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp index 309bc4e..e73300a 100644 --- a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp +++ b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp @@ -15,6 +15,7 @@ #include "llvm/ADT/Triple.h" #include "llvm/ADT/STLExtras.h" #include "llvm/Object/ObjectFile.h" +#include "llvm/Object/RelocVisitor.h" #include "llvm/DebugInfo/DIContext.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" @@ -28,6 +29,9 @@ #include "llvm/Support/system_error.h" #include <algorithm> #include <cstring> +#include <list> +#include <string> + using namespace llvm; using namespace object; @@ -67,6 +71,7 @@ static void DumpInput(const StringRef &Filename) { OwningPtr<ObjectFile> Obj(ObjectFile::createObjectFile(Buff.take())); StringRef DebugInfoSection; + RelocAddrMap RelocMap; StringRef DebugAbbrevSection; StringRef DebugLineSection; StringRef DebugArangesSection; @@ -97,6 +102,57 @@ static void DumpInput(const StringRef &Filename) { DebugStringSection = data; else if (name == "debug_ranges") DebugRangesSection = data; + // Any more debug info sections go here. + else + continue; + + // TODO: For now only handle relocations for the debug_info section. + if (name != "debug_info") + continue; + + if (i->begin_relocations() != i->end_relocations()) { + uint64_t SectionSize; + i->getSize(SectionSize); + for (relocation_iterator reloc_i = i->begin_relocations(), + reloc_e = i->end_relocations(); + reloc_i != reloc_e; reloc_i.increment(ec)) { + uint64_t Address; + reloc_i->getAddress(Address); + uint64_t Type; + reloc_i->getType(Type); + + RelocVisitor V(Obj->getFileFormatName()); + // The section address is always 0 for debug sections. + RelocToApply R(V.visit(Type, *reloc_i)); + if (V.error()) { + SmallString<32> Name; + error_code ec(reloc_i->getTypeName(Name)); + if (ec) { + errs() << "Aaaaaa! Nameless relocation! Aaaaaa!\n"; + } + errs() << "error: failed to compute relocation: " + << Name << "\n"; + continue; + } + + if (Address + R.Width > SectionSize) { + errs() << "error: " << R.Width << "-byte relocation starting " + << Address << " bytes into section " << name << " which is " + << SectionSize << " bytes long.\n"; + continue; + } + if (R.Width > 8) { + errs() << "error: can't handle a relocation of more than 8 bytes at " + "a time.\n"; + continue; + } + DEBUG(dbgs() << "Writing " << format("%p", R.Value) + << " at " << format("%p", Address) + << " with width " << format("%d", R.Width) + << "\n"); + RelocMap[Address] = std::make_pair(R.Width, R.Value); + } + } } OwningPtr<DIContext> dictx(DIContext::getDWARFContext(/*FIXME*/true, @@ -105,7 +161,8 @@ static void DumpInput(const StringRef &Filename) { DebugArangesSection, DebugLineSection, DebugStringSection, - DebugRangesSection)); + DebugRangesSection, + RelocMap)); if (Address == -1ULL) { outs() << Filename << ":\tfile format " << Obj->getFileFormatName() << "\n\n";
Apparently Analagous Threads
- [LLVMdev] [PATCH] basic reading reloc visitor for x86_64 ELF
- [LLVMdev] [llvm] r174463 - Initial support for DWARF CFI parsing and dumping in LLVM
- Fragmented DWARF
- [LLVMdev] Proposal for -filetype=obj full big endian support
- [LLVMdev] Proposal for -filetype=obj full big endian support