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[lld-macho] Don't include zero-size private label symbols in map file

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This is also what ld64 does. This will make it easier to compare their
respective map files.

Reviewed By: #lld-macho, thevinster

Differential Revision: https://reviews.llvm.org/D145654
This commit is contained in:
Jez Ng 2023-03-10 22:31:13 -05:00
parent 5b21395cc2
commit dd78e7334f
4 changed files with 21 additions and 10 deletions
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6
lld/MachO/InputFiles.cpp
View File

@ -634,12 +634,6 @@ void ObjFile::parseRelocations(ArrayRef<SectionHeader> sectionHeaders,
}
}
// Symbols with `l` or `L` as a prefix are linker-private and never appear in
// the output.
static bool isPrivateLabel(StringRef name) {
return name.startswith("l") || name.startswith("L");
}
template <class NList>
static macho::Symbol *createDefined(const NList &sym, StringRef name,
InputSection *isec, uint64_t value,

7
lld/MachO/MapFile.cpp
View File

@ -204,9 +204,10 @@ void macho::writeMapFile() {
if (auto *concatOsec = dyn_cast<ConcatOutputSection>(osec)) {
for (const InputSection *isec : concatOsec->inputs) {
for (Defined *sym : isec->symbols)
os << format("0x%08llX\t0x%08llX\t[%3u] %s\n", sym->getVA(),
sym->size, readerToFileOrdinal[sym->getFile()],
sym->getName().str().data());
if (!(isPrivateLabel(sym->getName()) && sym->size == 0))
os << format("0x%08llX\t0x%08llX\t[%3u] %s\n", sym->getVA(),
sym->size, readerToFileOrdinal[sym->getFile()],
sym->getName().str().data());
}
} else if (osec == in.cStringSection || osec == in.objcMethnameSection) {
const auto &liveCStrings = info.liveCStringsForSection.lookup(osec);

6
lld/MachO/Symbols.h
View File

@ -383,6 +383,12 @@ inline bool needsBinding(const Symbol *sym) {
return defined->isExternalWeakDef() || defined->interposable;
return false;
}
// Symbols with `l` or `L` as a prefix are linker-private and never appear in
// the output.
inline bool isPrivateLabel(StringRef name) {
return name.startswith("l") || name.startswith("L");
}
} // namespace macho
std::string toString(const macho::Symbol &);

12
lld/test/MachO/map-file.s
View File

@ -19,7 +19,7 @@
# CHECK: Sections:
# CHECK-NEXT: Idx Name Size VMA Type
# CHECK-NEXT: 0 __text 0000001b [[#%x,TEXT:]] TEXT
# CHECK-NEXT: 0 __text 0000001c [[#%x,TEXT:]] TEXT
# CHECK-NEXT: 1 __stubs 0000000c [[#%x,STUBS:]] TEXT
# CHECK-NEXT: 2 __stub_helper 0000001a [[#%x,HELPER:]] TEXT
# CHECK-NEXT: 3 __cstring 0000002b [[#%x,CSTR:]] DATA
@ -69,6 +69,7 @@
# CHECK-NEXT: 0x[[#%X,MAIN]] 0x00000019 [ 2] _main
# CHECK-NEXT: 0x[[#%X,BAR]] 0x00000001 [ 2] _bar
# CHECK-NEXT: 0x[[#%X,FOO]] 0x00000001 [ 3] __ZTIN3foo3bar4MethE
# CHECK-NEXT: 0x[[#%X,FOO+1]] 0x00000001 [ 3] ltmp1
# CHECK-NEXT: 0x[[#%X,STUBS]] 0x00000006 [ 5] _baz
# CHECK-NEXT: 0x[[#%X,STUBS+6]] 0x00000006 [ 2] _bar
# CHECK-NEXT: 0x[[#%X,HELPER]] 0x0000001A [ 0] helper helper
@ -86,6 +87,7 @@
# CHECK-NEXT: 0x[[#%X,DYLD]] 0x00000000 [ 0] __dyld_private
# CHECK-NEXT: 0x[[#%X,TLVP]] 0x00000008 [ 0] non-lazy-pointer-to-local: _baz_tlv
# CHECK-NEXT: 0x[[#%X,BSS]] 0x00000001 [ 2] _number
# CHECK-EMPTY:
# MAPFILE: "name":"Total Write map file"
@ -115,11 +117,19 @@
#--- foo.s
.globl __ZTIN3foo3bar4MethE
## This should not appear in the map file since it is a zero-size private label
## symbol.
ltmp0:
## This C++ symbol makes it clear that we do not print the demangled name in
## the map file, even if `-demangle` is passed.
__ZTIN3foo3bar4MethE:
nop
## This private label symbol will appear in the map file since it has nonzero
## size.
ltmp1:
nop
.subsections_via_symbols
#--- test.s