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[llvm-objcopy][MachO] Add llvm-strip support for newer load commands
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Previously llvm-strip would fail because of unknown commands.

Fixes https://bugs.llvm.org/show_bug.cgi?id=50044

Differential Revision: https://reviews.llvm.org/D113734
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@keith
keith committed Nov 17, 2021
1 parent 3e957e5 commit 68311f2
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Showing 9 changed files with 341 additions and 1 deletion.
238 changes: 238 additions & 0 deletions llvm/test/tools/llvm-objcopy/MachO/Inputs/strip-chained-fixups.yaml
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@@ -0,0 +1,238 @@
--- !mach-o
FileHeader:
magic: 0xFEEDFACF
cputype: 0x100000C
cpusubtype: 0x0
filetype: 0x2
ncmds: 16
sizeofcmds: 744
flags: 0x200085
reserved: 0x0
LoadCommands:
- cmd: LC_SEGMENT_64
cmdsize: 72
segname: __PAGEZERO
vmaddr: 0
vmsize: 4294967296
fileoff: 0
filesize: 0
maxprot: 0
initprot: 0
nsects: 0
flags: 0
- cmd: LC_SEGMENT_64
cmdsize: 232
segname: __TEXT
vmaddr: 4294967296
vmsize: 16384
fileoff: 0
filesize: 16384
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nsects: 2
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content: 010000001C000000000000001C000000000000001C00000002000000983F00003400000034000000B13F00000000000034000000030000000C0002001400020000000001040000000010000200000002
- cmd: LC_SEGMENT_64
cmdsize: 72
segname: __LINKEDIT
vmaddr: 4294983680
vmsize: 16384
fileoff: 16384
filesize: 753
maxprot: 1
initprot: 1
nsects: 0
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- cmd: LC_DYLD_CHAINED_FIXUPS
cmdsize: 16
dataoff: 16384
datasize: 56
- cmd: LC_DYLD_EXPORTS_TRIE
cmdsize: 16
dataoff: 16440
datasize: 56
- cmd: LC_SYMTAB
cmdsize: 24
symoff: 16504
nsyms: 15
stroff: 16744
strsize: 120
- cmd: LC_DYSYMTAB
cmdsize: 80
ilocalsym: 0
nlocalsym: 12
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nextdefsym: 3
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- cmd: LC_LOAD_DYLINKER
cmdsize: 32
name: 12
Content: '/usr/lib/dyld'
ZeroPadBytes: 7
- cmd: LC_UUID
cmdsize: 24
uuid: F445529E-643C-3A38-8F59-AB64566BCAFF
- cmd: LC_BUILD_VERSION
cmdsize: 32
platform: 1
minos: 786432
sdk: 786432
ntools: 1
Tools:
- tool: 3
version: 46596096
- cmd: LC_SOURCE_VERSION
cmdsize: 16
version: 0
- cmd: LC_MAIN
cmdsize: 24
entryoff: 16284
stacksize: 0
- cmd: LC_LOAD_DYLIB
cmdsize: 56
dylib:
name: 24
timestamp: 2
current_version: 85917696
compatibility_version: 65536
Content: '/usr/lib/libSystem.B.dylib'
ZeroPadBytes: 6
- cmd: LC_FUNCTION_STARTS
cmdsize: 16
dataoff: 16496
datasize: 8
- cmd: LC_DATA_IN_CODE
cmdsize: 16
dataoff: 16504
datasize: 0
- cmd: LC_CODE_SIGNATURE
cmdsize: 16
dataoff: 16864
datasize: 273
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StringTable:
- ' '
- __mh_execute_header
- _foo
- _main
- '/tmp/'
- main.c
- '/var/folders/gj/wf3swl0x215b2sq1qy84kzkm0000gn/T/main-e32fe7.o'
- _foo
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...
10 changes: 10 additions & 0 deletions llvm/test/tools/llvm-objcopy/MachO/strip-all.test
View file
Expand Up @@ -2,6 +2,7 @@

# RUN: yaml2obj %p/Inputs/strip-all.yaml -o %t.exec
# RUN: yaml2obj %p/Inputs/strip-all-with-dwarf.yaml -o %t.dwarf
# RUN: yaml2obj %p/Inputs/strip-chained-fixups.yaml -o %t.fixups

## Check that the symbol list satisfies the order: local / defined external /
## undefined external, otherwise llvm-objcopy will fail.
Expand All @@ -15,6 +16,10 @@
# RUN: llvm-readobj --sections --relocations --symbols %t.dwarf.stripped \
# RUN: | FileCheck --check-prefixes=COMMON,DWARF %s

# RUN: llvm-objcopy --strip-all %t.fixups %t.fixups.stripped
# RUN: llvm-readobj --sections --relocations --symbols %t.fixups.stripped \
# RUN: | FileCheck --check-prefix=COMMON %s

## The output of "llvm-strip" should be identical with that of
## "llvm-strip --strip-all" and "llvm-objcopy --strip-all".
# RUN: llvm-strip %t.exec -o %t2
Expand All @@ -32,6 +37,11 @@
# RUN: llvm-lipo %t.dwarf.universal.stripped -thin x86_64 -output %t6
# RUN: cmp %t6 %t.dwarf.stripped

# RUN: llvm-strip %t.exec -o %t7
# RUN: llvm-strip --strip-all %t.exec -o %t8
# cmp %t7 %t.fixups.stripped
# cmp %t8 %t.fixups.stripped

## Make sure that debug sections are removed.
# DWARF: Sections [
# DWARF-NOT: Name: __debug_str
Expand Down
14 changes: 13 additions & 1 deletion llvm/tools/llvm-objcopy/MachO/MachOLayoutBuilder.cpp
View file
Expand Up @@ -249,8 +249,12 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
uint64_t StartOfExportTrie =
StartOfLazyBindingInfo + O.LazyBinds.Opcodes.size();
uint64_t StartOfFunctionStarts = StartOfExportTrie + O.Exports.Trie.size();
uint64_t StartOfDataInCode =
uint64_t StartOfDyldExportsTrie =
StartOfFunctionStarts + O.FunctionStarts.Data.size();
uint64_t StartOfChainedFixups =
StartOfDyldExportsTrie + O.ExportsTrie.Data.size();
uint64_t StartOfDataInCode =
StartOfChainedFixups + O.ChainedFixups.Data.size();
uint64_t StartOfLinkerOptimizationHint =
StartOfDataInCode + O.DataInCode.Data.size();
uint64_t StartOfSymbols =
Expand Down Expand Up @@ -353,6 +357,14 @@ Error MachOLayoutBuilder::layoutTail(uint64_t Offset) {
MLC.linkedit_data_command_data.dataoff = StartOfFunctionStarts;
MLC.linkedit_data_command_data.datasize = O.FunctionStarts.Data.size();
break;
case MachO::LC_DYLD_CHAINED_FIXUPS:
MLC.linkedit_data_command_data.dataoff = StartOfChainedFixups;
MLC.linkedit_data_command_data.datasize = O.ChainedFixups.Data.size();
break;
case MachO::LC_DYLD_EXPORTS_TRIE:
MLC.linkedit_data_command_data.dataoff = StartOfDyldExportsTrie;
MLC.linkedit_data_command_data.datasize = O.ExportsTrie.Data.size();
break;
case MachO::LC_DYLD_INFO:
case MachO::LC_DYLD_INFO_ONLY:
MLC.dyld_info_command_data.rebase_off =
Expand Down
16 changes: 16 additions & 0 deletions llvm/tools/llvm-objcopy/MachO/MachOReader.cpp
View file
Expand Up @@ -174,6 +174,12 @@ Error MachOReader::readLoadCommands(Object &O) const {
case MachO::LC_FUNCTION_STARTS:
O.FunctionStartsCommandIndex = O.LoadCommands.size();
break;
case MachO::LC_DYLD_EXPORTS_TRIE:
O.ExportsTrieCommandIndex = O.LoadCommands.size();
break;
case MachO::LC_DYLD_CHAINED_FIXUPS:
O.ChainedFixupsCommandIndex = O.LoadCommands.size();
break;
}
#define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct) \
case MachO::LCName: \
Expand Down Expand Up @@ -301,6 +307,14 @@ void MachOReader::readFunctionStartsData(Object &O) const {
return readLinkData(O, O.FunctionStartsCommandIndex, O.FunctionStarts);
}

void MachOReader::readExportsTrie(Object &O) const {
return readLinkData(O, O.ExportsTrieCommandIndex, O.ExportsTrie);
}

void MachOReader::readChainedFixups(Object &O) const {
return readLinkData(O, O.ChainedFixupsCommandIndex, O.ChainedFixups);
}

void MachOReader::readIndirectSymbolTable(Object &O) const {
MachO::dysymtab_command DySymTab = MachOObj.getDysymtabLoadCommand();
constexpr uint32_t AbsOrLocalMask =
Expand Down Expand Up @@ -352,6 +366,8 @@ Expected<std::unique_ptr<Object>> MachOReader::create() const {
readDataInCodeData(*Obj);
readLinkerOptimizationHint(*Obj);
readFunctionStartsData(*Obj);
readExportsTrie(*Obj);
readChainedFixups(*Obj);
readIndirectSymbolTable(*Obj);
readSwiftVersion(*Obj);
return std::move(Obj);
Expand Down
2 changes: 2 additions & 0 deletions llvm/tools/llvm-objcopy/MachO/MachOReader.h
View file
Expand Up @@ -41,6 +41,8 @@ class MachOReader : public Reader {
void readDataInCodeData(Object &O) const;
void readLinkerOptimizationHint(Object &O) const;
void readFunctionStartsData(Object &O) const;
void readExportsTrie(Object &O) const;
void readChainedFixups(Object &O) const;
void readIndirectSymbolTable(Object &O) const;
void readSwiftVersion(Object &O) const;

Expand Down

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