AcoSail/llvm-project
8
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[Propeller] Make decoding BBAddrMaps trace through relocations

Browse Source 
Currently when using the LLVM tools (eg llvm-readobj, llvm-objdump) to
find information about basic block locations using the propeller tooling
in relocatable object files function addresses are not mapped properly
which causes problems. In llvm-readobj this means that incorrect
function names will be pulled. In llvm-objdum this means that most BBs
won't show up in the output if --symbolize-operands is used. This patch
changes the behavior of decodeBBAddrMap to trace through relocations
to get correct function addresses if it is going through a relocatable
object file. This fixes the behavior in both tools and also other
consumers of decodeBBAddrMap. Some helper functions have been added
in/refactoring done to aid in grabbing BB address map sections now that
in some cases both relocation and BB address map sections need to be
obtained at the same time.

Regression tests moved around/added.

Differential Revision: https://reviews.llvm.org/D143841
This commit is contained in:
Aiden Grossman 2023-02-25 10:18:57 +00:00
parent 60d2dbf522
commit 175aa049c7
8 changed files with 394 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
llvm/include/llvm/Object/ELF.h
View File

@ -392,7 +392,8 @@ public:
Expected<ArrayRef<T>> getSectionContentsAsArray(const Elf_Shdr &Sec) const;
Expected<ArrayRef<uint8_t>> getSectionContents(const Elf_Shdr &Sec) const;
Expected<ArrayRef<uint8_t>> getSegmentContents(const Elf_Phdr &Phdr) const;
Expected<std::vector<BBAddrMap>> decodeBBAddrMap(const Elf_Shdr &Sec) const;
Expected<std::vector<BBAddrMap>>
decodeBBAddrMap(const Elf_Shdr &Sec, const Elf_Shdr *RelaSec = nullptr) const;
/// Returns a map from every section matching \p IsMatch to its relocation
/// section, or \p nullptr if it has no relocation section. This function

34
llvm/lib/Object/ELF.cpp
View File

@ -640,7 +640,26 @@ ELFFile<ELFT>::toMappedAddr(uint64_t VAddr, WarningHandler WarnHandler) const {
template <class ELFT>
Expected<std::vector<BBAddrMap>>
ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec) const {
ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec,
const Elf_Shdr *RelaSec) const {
bool IsRelocatable = getHeader().e_type == ELF::ET_REL;
// This DenseMap maps the offset of each function (the location of the
// reference to the function in the SHT_LLVM_BB_ADDR_MAP section) to the
// addend (the location of the function in the text section).
llvm::DenseMap<uint64_t, uint64_t> FunctionOffsetTranslations;
if (IsRelocatable && RelaSec) {
assert(RelaSec &&
"Can't read a SHT_LLVM_BB_ADDR_MAP section in a relocatable "
"object file without providing a relocation section.");
Expected<Elf_Rela_Range> Relas = this->relas(*RelaSec);
if (!Relas)
return createError("unable to read relocations for section " +
describe(*this, Sec) + ": " +
toString(Relas.takeError()));
for (Elf_Rela Rela : *Relas)
FunctionOffsetTranslations[Rela.r_offset] = Rela.r_addend;
}
Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
if (!ContentsOrErr)
return ContentsOrErr.takeError();
@ -680,7 +699,20 @@ ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec) const {
Twine(static_cast<int>(Version)));
Data.getU8(Cur); // Feature byte
}
uint64_t SectionOffset = Cur.tell();
uintX_t Address = static_cast<uintX_t>(Data.getAddress(Cur));
if (!Cur)
return Cur.takeError();
if (IsRelocatable) {
assert(Address == 0);
auto FOTIterator = FunctionOffsetTranslations.find(SectionOffset);
if (FOTIterator == FunctionOffsetTranslations.end()) {
return createError("failed to get relocation data for offset: " +
Twine::utohexstr(SectionOffset) + " in section " +
describe(*this, Sec));
}
Address = FOTIterator->second;
}
uint32_t NumBlocks = ReadULEB128AsUInt32();
std::vector<BBAddrMap::BBEntry> BBEntries;
uint32_t PrevBBEndOffset = 0;

41
llvm/lib/Object/ELFObjectFile.cpp
View File

@ -681,24 +681,39 @@ template <class ELFT>
Expected<std::vector<BBAddrMap>> static readBBAddrMapImpl(
const ELFFile<ELFT> &EF, std::optional<unsigned> TextSectionIndex) {
using Elf_Shdr = typename ELFT::Shdr;
bool IsRelocatable = EF.getHeader().e_type == ELF::ET_REL;
std::vector<BBAddrMap> BBAddrMaps;
const auto &Sections = cantFail(EF.sections());
for (const Elf_Shdr &Sec : Sections) {
auto IsMatch = [&](const Elf_Shdr &Sec) -> Expected<bool> {
if (Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP &&
Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP_V0)
continue;
if (TextSectionIndex) {
Expected<const Elf_Shdr *> TextSecOrErr = EF.getSection(Sec.sh_link);
if (!TextSecOrErr)
return createError("unable to get the linked-to section for " +
describe(EF, Sec) + ": " +
toString(TextSecOrErr.takeError()));
if (*TextSectionIndex != std::distance(Sections.begin(), *TextSecOrErr))
continue;
}
Expected<std::vector<BBAddrMap>> BBAddrMapOrErr = EF.decodeBBAddrMap(Sec);
return false;
if (!TextSectionIndex)
return true;
Expected<const Elf_Shdr *> TextSecOrErr = EF.getSection(Sec.sh_link);
if (!TextSecOrErr)
return createError("unable to get the linked-to section for " +
describe(EF, Sec) + ": " +
toString(TextSecOrErr.takeError()));
if (*TextSectionIndex != std::distance(Sections.begin(), *TextSecOrErr))
return false;
return true;
};
Expected<MapVector<const Elf_Shdr *, const Elf_Shdr *>> SectionRelocMapOrErr =
EF.getSectionAndRelocations(IsMatch);
if (!SectionRelocMapOrErr)
return SectionRelocMapOrErr.takeError();
for (auto const &[Sec, RelocSec] : *SectionRelocMapOrErr) {
if (IsRelocatable && !RelocSec)
return createError("unable to get relocation section for " +
describe(EF, *Sec));
Expected<std::vector<BBAddrMap>> BBAddrMapOrErr =
EF.decodeBBAddrMap(*Sec, RelocSec);
if (!BBAddrMapOrErr)
return createError("unable to read " + describe(EF, Sec) + ": " +
return createError("unable to read " + describe(EF, *Sec) + ": " +
toString(BBAddrMapOrErr.takeError()));
std::move(BBAddrMapOrErr->begin(), BBAddrMapOrErr->end(),
std::back_inserter(BBAddrMaps));

11
llvm/test/tools/llvm-objdump/X86/elf-bbaddrmap-disassemble-symbolize-operands.yaml
View File

@ -5,19 +5,12 @@
# UNSUPPORTED: system-windows
## Executable object file.
# RUN: yaml2obj --docnum=1 -DTYPE=ET_EXEC -DFOO_ADDR=0x4000 -DBAR_ADDR=0x5000 %s -o %t1
# RUN: yaml2obj --docnum=1 -DFOO_ADDR=0x4000 -DBAR_ADDR=0x5000 %s -o %t1
# RUN: llvm-objdump %t1 -d --symbolize-operands -M intel --no-show-raw-insn --no-leading-addr | \
# RUN: FileCheck %s -DSYM=symbol --match-full-lines --check-prefixes=INTEL
# RUN: llvm-objdump %t1 -d --symbolize-operands -M att --no-show-raw-insn --no-leading-addr | \
# RUN: FileCheck %s -DSYM=symbol --match-full-lines --check-prefixes=ATT
## Relocatable object file.
# RUN: yaml2obj --docnum=1 -DTYPE=ET_REL -DFOO_ADDR=0x0 -DBAR_ADDR=0x0 %s -o %t2
# RUN: llvm-objdump %t2 -d --symbolize-operands -M intel --no-show-raw-insn --no-leading-addr | \
# RUN: FileCheck %s -DSYM=foo+0x200c --match-full-lines --check-prefix=INTEL
# RUN: llvm-objdump %t2 -d --symbolize-operands -M att --no-show-raw-insn --no-leading-addr | \
# RUN: FileCheck %s -DSYM=foo+0x200c --match-full-lines --check-prefix=ATT
## Executable object file with a single SHT_LLVM_BB_ADDR_MAP for multiple text sections.
# RUN: yaml2obj --docnum=2 %s -o %t3
# RUN: llvm-objdump %t3 -d --symbolize-operands -M intel --no-show-raw-insn --no-leading-addr | \
@ -78,7 +71,7 @@
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: [[TYPE]]
Type: ET_EXEC
Machine: EM_X86_64
Sections:
- Name: .text.foo

91
llvm/test/tools/llvm-objdump/X86/elf-bbaddrmap-symbolize-relocatable.yaml Normal file
View File

@ -0,0 +1,91 @@
## Test that in the presence of SHT_LLVM_BB_ADDR_MAP sections,
## --symbolize-operands can display <BB*> labels properly in a relocatable
## object file.
## Fails on windows (https://github.com/llvm/llvm-project/issues/60013).
# UNSUPPORTED: system-windows
## Relocatable Object file.
# RUN: yaml2obj %s -o %t1
# RUN: llvm-objdump %t1 -d --symbolize-operands -M att --no-show-raw-insn --no-leading-addr | \
# RUN: FileCheck %s -DSYM=symbol --match-full-lines
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
SectionHeaderStringTable: .strtab
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
Content: FFFF
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Link: .text
Entries:
- Version: 2
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0x1
Metadata: 0x1
- Version: 2
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0x1
Metadata: 0x1
- Name: .rela.llvm_bb_addr_map
Type: SHT_RELA
Flags: [ SHF_INFO_LINK ]
Link: .symtab
Info: .llvm_bb_addr_map
Relocations:
- Offset: 0x2
Symbol: .text
Type: R_X86_64_64
- Offset: 0x11
Symbol: .text
Type: R_X86_64_64
Addend: 1
Symbols:
- Name: a
Section: .text
Value: 0x0
- Name: c
Section: .text
Value: 0x1
- Name: .text
Type: STT_SECTION
Section: .text
# CHECK: <a>:
# CHECK-NEXT: <BB0>:
# CHECK: <c>:
# CHECK-NEXT: <BB0>:
## Check that if we're missing a relocation section we get the appropriate
## warning.
# RUN: yaml2obj %s --docnum=2 -o %t2
# RUN: llvm-readobj %t2 --bb-addr-map 2>&1 | FileCheck %s --check-prefix=NO-RELA-SECTION -DFILE=%t2
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
Content: FF
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Link: .text
# NO-RELA-SECTION: warning: '[[FILE]]': unable to get relocation section for SHT_LLVM_BB_ADDR_MAP section with index 2

211
llvm/test/tools/llvm-readobj/ELF/bb-addr-map-relocatable.test Normal file
View File

@ -0,0 +1,211 @@
## This test checks how we handle the --bb-addr-map option on relocatable
## object files.
## Fails on windows (https://github.com/llvm/llvm-project/issues/60013).
# UNSUPPORTED: system-windows
# RUN: yaml2obj %s -o %t1.o
# RUN: llvm-readobj %t1.o --bb-addr-map | FileCheck %s
# CHECK: BBAddrMap [
# CHECK-NEXT: Function {
# CHECK-NEXT: At: 0x0
# CHECK-NEXT: Name: <?>
# CHECK-NEXT: BB entries [
# CHECK-NEXT: {
# CHECK-NEXT: ID: 0
# CHECK-NEXT: Offset: 0x0
# CHECK-NEXT: Size: 0xF
# CHECK-NEXT: HasReturn: Yes
# CHECK-NEXT: HasTailCall: No
# CHECK-NEXT: IsEHPad: No
# CHECK-NEXT: CanFallThrough: No
# CHECK-NEXT: }
# CHECK-NEXT: ]
# CHECK-NEXT: }
# CHECK-NEXT: Function {
# CHECK-NEXT: At: 0x10
# CHECK-NEXT: Name: <?>
# CHECK-NEXT: BB entries [
# CHECK-NEXT: {
# CHECK-NEXT: ID: 0
# CHECK-NEXT: Offset: 0x0
# CHECK-NEXT: Size: 0x11
# CHECK-NEXT: HasReturn: No
# CHECK-NEXT: HasTailCall: No
# CHECK-NEXT: IsEHPad: No
# CHECK-NEXT: CanFallThrough: Yes
# CHECK-NEXT: }
# CHECK-NEXT: ]
# CHECK-NEXT: }
# CHECK-NEXT: ]
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Link: .text
Entries:
- Version: 2
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0xF
Metadata: 0x1
- Version: 2
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0x11
Metadata: 0x8
- Name: .rela.llvm_bb_addr_map
Type: SHT_RELA
Flags: [ SHF_INFO_LINK ]
Link: .symtab
Info: .llvm_bb_addr_map
Relocations:
- Offset: 0x2
Symbol: .text
Type: R_X86_64_64
- Offset: 0x11
Symbol: .text
Type: R_X86_64_64
Addend: 16
Symbols:
- Name: a
Section: .text
Value: 0x0
- Name: c
Section: .text
Value: 0x10
- Name: .text
Type: STT_SECTION
Section: .text
## Check that if we have a relocatable file and no relocation section for
## a SHT_LLVM_BB_ADDR_MAP section, we give the appropriate warnings.
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Link: .text
# RUN: yaml2obj %s --docnum=2 -o %t2.o
# RUN: llvm-readobj %t2.o --bb-addr-map 2>&1 | FileCheck %s --check-prefix=NO-RELA -DFILE=%t2.o
# NO-RELA: warning: '[[FILE]]': unable to get relocation section for SHT_LLVM_BB_ADDR_MAP section with index 2
## Check that we get a warning if we expect a relocation and it is not present.
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Link: .text
Entries:
- Version: 2
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0xF
Metadata: 0x1
- Name: .rela.llvm_bb_addr_map
Type: SHT_RELA
Flags: [ SHF_INFO_LINK ]
Info: .llvm_bb_addr_map
# RUN: yaml2obj %s --docnum=3 -o %t3.o
# RUN: llvm-readobj %t3.o --bb-addr-map 2>&1 | FileCheck %s --check-prefix=MISSING-RELOCATION -DFILE=%t3.o
# MISSING-RELOCATION: warning: '[[FILE]]': unable to dump SHT_LLVM_BB_ADDR_MAP section with index 2: failed to get relocation data for offset: 2 in section SHT_LLVM_BB_ADDR_MAP section with index 2
## Check that if we have a missing relocated section, we fail and give the
## appropriate warning.
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
Sections:
- Name: .rela.llvm_bb_addr_map
Type: SHT_RELA
Flags: [ SHF_INFO_LINK ]
Info: 0xFF
# RUN: yaml2obj %s --docnum=4 -o %t4.o
# RUN: llvm-readobj %t4.o --bb-addr-map 2>&1 | FileCheck %s --check-prefix=NO-RELOCATED-SECTION -DFILE=%t4.o
# NO-RELOCATED-SECTION: warning: '[[FILE]]': failed to get SHT_LLVM_BB_ADDR_MAP section(s): SHT_RELA section with index 1: failed to get a relocated section: invalid section index: 255
## Check that if we have an ET_DYN file with a .rela.dyn section, we don't get
## a warning about a missing relocation section and can get the baddrmap data.
--- !ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_DYN
Machine: EM_X86_64
Sections:
- Name: .rela.dyn
Type: SHT_RELA
Flags: [ SHF_ALLOC ]
- Name: .llvm_bb_addr_map
Type: SHT_LLVM_BB_ADDR_MAP
Flags: [ SHF_LINK_ORDER ]
Entries:
- Version: 2
Address: 0xF
BBEntries:
- ID: 0
AddressOffset: 0x0
Size: 0xF
Metadata: 0x1
# RUN: yaml2obj %s --docnum=5 -o %t5.o
# RUN: llvm-readobj %t5.o --bb-addr-map 2>&1 | FileCheck %s --check-prefix=ET-DYN-NO-WARNING -DFILE=%t5.o
# ET-DYN-NO-WARNING: BBAddrMap [
# ET-DYN-NO-WARNING: Function {
# ET-DYN-NO-WARNING: At: 0xF
# ET-DYN-NO-WARNING: Name: <?>
# ET-DYN-NO-WARNING: BB entries [
# ET-DYN-NO-WARNING: {
# ET-DYN-NO-WARNING: ID: 0
# ET-DYN-NO-WARNING: Offset: 0x0
# ET-DYN-NO-WARNING: Size: 0xF
# ET-DYN-NO-WARNING: HasReturn: Yes
# ET-DYN-NO-WARNING: HasTailCall: No
# ET-DYN-NO-WARNING: IsEHPad: No
# ET-DYN-NO-WARNING: CanFallThrough: No
# ET-DYN-NO-WARNING: }
# ET-DYN-NO-WARNING: ]
# ET-DYN-NO-WARNING: }
# ET-DYN-NO-WARNING: ]

4
llvm/tools/llvm-objdump/llvm-objdump.cpp
View File

@ -1439,8 +1439,10 @@ static void disassembleObject(const Target *TheTarget, ObjectFile &Obj,
AddrToBBAddrMap.clear();
if (const auto *Elf = dyn_cast<ELFObjectFileBase>(&Obj)) {
auto BBAddrMapsOrErr = Elf->readBBAddrMap(SectionIndex);
if (!BBAddrMapsOrErr)
if (!BBAddrMapsOrErr) {
reportWarning(toString(BBAddrMapsOrErr.takeError()), Obj.getFileName());
return;
}
for (auto &FunctionBBAddrMap : *BBAddrMapsOrErr)
AddrToBBAddrMap.emplace(FunctionBBAddrMap.Addr,
std::move(FunctionBBAddrMap));

34
llvm/tools/llvm-readobj/ELFDumper.cpp
View File

@ -7173,21 +7173,35 @@ template <class ELFT> void LLVMELFDumper<ELFT>::printCGProfile() {
template <class ELFT> void LLVMELFDumper<ELFT>::printBBAddrMaps() {
bool IsRelocatable = this->Obj.getHeader().e_type == ELF::ET_REL;
for (const Elf_Shdr &Sec : cantFail(this->Obj.sections())) {
if (Sec.sh_type != SHT_LLVM_BB_ADDR_MAP &&
Sec.sh_type != SHT_LLVM_BB_ADDR_MAP_V0) {
continue;
}
using Elf_Shdr = typename ELFT::Shdr;
auto IsMatch = [](const Elf_Shdr &Sec) -> bool {
return Sec.sh_type == ELF::SHT_LLVM_BB_ADDR_MAP ||
Sec.sh_type == ELF::SHT_LLVM_BB_ADDR_MAP_V0;
};
Expected<MapVector<const Elf_Shdr *, const Elf_Shdr *>> SecRelocMapOrErr =
this->Obj.getSectionAndRelocations(IsMatch);
if (!SecRelocMapOrErr) {
this->reportUniqueWarning(
"failed to get SHT_LLVM_BB_ADDR_MAP section(s): " +
toString(SecRelocMapOrErr.takeError()));
return;
}
for (auto const &[Sec, RelocSec] : *SecRelocMapOrErr) {
std::optional<const Elf_Shdr *> FunctionSec;
if (IsRelocatable)
FunctionSec =
unwrapOrError(this->FileName, this->Obj.getSection(Sec.sh_link));
unwrapOrError(this->FileName, this->Obj.getSection(Sec->sh_link));
ListScope L(W, "BBAddrMap");
if (IsRelocatable && !RelocSec) {
this->reportUniqueWarning("unable to get relocation section for " +
this->describe(*Sec));
continue;
}
Expected<std::vector<BBAddrMap>> BBAddrMapOrErr =
this->Obj.decodeBBAddrMap(Sec);
this->Obj.decodeBBAddrMap(*Sec, RelocSec);
if (!BBAddrMapOrErr) {
this->reportUniqueWarning("unable to dump " + this->describe(Sec) + ": " +
toString(BBAddrMapOrErr.takeError()));
this->reportUniqueWarning("unable to dump " + this->describe(*Sec) +
": " + toString(BBAddrMapOrErr.takeError()));
continue;
}
for (const BBAddrMap &AM : *BBAddrMapOrErr) {
@ -7199,7 +7213,7 @@ template <class ELFT> void LLVMELFDumper<ELFT>::printBBAddrMaps() {
if (FuncSymIndex.empty())
this->reportUniqueWarning(
"could not identify function symbol for address (0x" +
Twine::utohexstr(AM.Addr) + ") in " + this->describe(Sec));
Twine::utohexstr(AM.Addr) + ") in " + this->describe(*Sec));
else
FuncName = this->getStaticSymbolName(FuncSymIndex.front());
W.printString("Name", FuncName);