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[LLD][COFF] Make /wholearchive thin-archive member identifiers consistent (#145487)

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A thin archive is an archive/library format where the archive itself
contains only references to member object files on disk, rather than
embedding the file contents.

For the non-/wholearchive case, we use the path to the archive member as
the identifier for thin-archive members (see comments in
`enqueueArchiveMember`). This patch modifies the /wholearchive path to
behave the same way.

Apart from consistency, my motivation for fixing this is DTLTO
(#126654), where having the member identifier be the path on disk allows
distribution of bitcode members during ThinLTO.

(cherry picked from commit 9f733f4324412ef89cc7729bf027cdcab912ceff)
This commit is contained in:
bd1976bris 2025-07-22 16:57:20 +01:00 committed by Tobias Hieta
parent f66e874504
commit 64a274fada
3 changed files with 42 additions and 20 deletions
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24
lld/COFF/Driver.cpp
View File

@ -274,8 +274,13 @@ void LinkerDriver::addBuffer(std::unique_ptr<MemoryBuffer> mb,
make<std::unique_ptr<Archive>>(std::move(file)); // take ownership
int memberIndex = 0;
for (MemoryBufferRef m : getArchiveMembers(ctx, archive))
addArchiveBuffer(m, "<whole-archive>", filename, memberIndex++);
for (MemoryBufferRef m : getArchiveMembers(ctx, archive)) {
if (!archive->isThin())
addArchiveBuffer(m, "<whole-archive>", filename, memberIndex++);
else
addThinArchiveBuffer(m, "<whole-archive>");
}
return;
}
addFile(make<ArchiveFile>(ctx, mbref));
@ -386,6 +391,14 @@ void LinkerDriver::addArchiveBuffer(MemoryBufferRef mb, StringRef symName,
Log(ctx) << "Loaded " << obj << " for " << symName;
}
void LinkerDriver::addThinArchiveBuffer(MemoryBufferRef mb, StringRef symName) {
// Pass an empty string as the archive name and an offset of 0 so that
// the original filename is used as the buffer identifier. This is
// useful for DTLTO, where having the member identifier be the actual
// path on disk enables distribution of bitcode files during ThinLTO.
addArchiveBuffer(mb, symName, /*parentName=*/"", /*OffsetInArchive=*/0);
}
void LinkerDriver::enqueueArchiveMember(const Archive::Child &c,
const Archive::Symbol &sym,
StringRef parentName) {
@ -422,11 +435,8 @@ void LinkerDriver::enqueueArchiveMember(const Archive::Child &c,
reportBufferError(errorCodeToError(mbOrErr.second), childName);
llvm::TimeTraceScope timeScope("Archive: ",
mbOrErr.first->getBufferIdentifier());
// Pass empty string as archive name so that the original filename is
// used as the buffer identifier.
ctx.driver.addArchiveBuffer(takeBuffer(std::move(mbOrErr.first)),
toCOFFString(ctx, sym), "",
/*OffsetInArchive=*/0);
ctx.driver.addThinArchiveBuffer(takeBuffer(std::move(mbOrErr.first)),
toCOFFString(ctx, sym));
});
}

1
lld/COFF/Driver.h
View File

@ -173,6 +173,7 @@ private:
bool lazy);
void addArchiveBuffer(MemoryBufferRef mbref, StringRef symName,
StringRef parentName, uint64_t offsetInArchive);
void addThinArchiveBuffer(MemoryBufferRef mbref, StringRef symName);
void enqueueTask(std::function<void()> task);
bool run();

37
lld/test/COFF/thin-archive.s
View File

@ -22,23 +22,34 @@
# SYMTAB: ?f@@YAHXZ in
# NO-SYMTAB-NOT: ?f@@YAHXZ in
# RUN: lld-link /entry:main %t.main.obj %t.lib /out:%t.exe 2>&1 | \
# RUN: FileCheck --allow-empty %s
# RUN: lld-link /entry:main %t.main.obj %t_thin.lib /out:%t.exe 2>&1 | \
# RUN: FileCheck --allow-empty %s
# RUN: lld-link /entry:main %t.main.obj /wholearchive:%t_thin.lib /out:%t.exe 2>&1 | \
# RUN: FileCheck --allow-empty %s
# RUN: echo "/entry:main \"%t.main.obj\" /out:\"%t.exe\"" > %t.rsp
# RUN: lld-link @%t.rsp %t.lib /verbose 2>&1 | \
# RUN: FileCheck %s --check-prefix=LOAD_NON_THIN
# RUN: lld-link @%t.rsp %t_thin.lib /verbose 2>&1 | \
# RUN: FileCheck %s --check-prefix=LOAD_THIN_SYM
# RUN: lld-link @%t.rsp /wholearchive:%t_thin.lib /verbose 2>&1 | \
# RUN: FileCheck %s --check-prefix=LOAD_THIN_WHOLE
# RUN: lld-link @%t.rsp /wholearchive %t_thin.lib /verbose 2>&1 | \
# RUN: FileCheck %s --check-prefix=LOAD_THIN_WHOLE
# LOAD_NON_THIN: Loaded {{.*}}.lib({{.*}}.obj) for int __cdecl f(void)
# LOAD_THIN_SYM: Loaded {{.*}}.obj for int __cdecl f(void)
# LOAD_THIN_WHOLE: Loaded {{.*}}.obj for <whole-archive>
# RUN: rm %t.lib.obj
# RUN: lld-link /entry:main %t.main.obj %t.lib /out:%t.exe 2>&1 | \
# RUN: FileCheck --allow-empty %s
# RUN: env LLD_IN_TEST=1 not lld-link /entry:main %t.main.obj %t_thin.lib \
# RUN: /out:%t.exe 2>&1 | FileCheck --check-prefix=NOOBJ %s
# RUN: env LLD_IN_TEST=1 not lld-link /entry:main %t.main.obj %t_thin.lib /out:%t.exe \
# RUN: /demangle:no 2>&1 | FileCheck --check-prefix=NOOBJNODEMANGLE %s
# RUN: lld-link @%t.rsp %t.lib 2>&1 | \
# RUN: FileCheck %s --check-prefix=ERR --allow-empty
# RUN: env LLD_IN_TEST=1 not lld-link @%t.rsp %t_thin.lib 2>&1 | \
# RUN: FileCheck %s --check-prefix=NOOBJ
# RUN: env LLD_IN_TEST=1 not lld-link @%t.rsp /wholearchive:%t_thin.lib 2>&1 | \
# RUN: FileCheck %s --check-prefix=NOOBJWHOLE
# RUN: env LLD_IN_TEST=1 not lld-link @%t.rsp %t_thin.lib /demangle:no 2>&1 | \
# RUN: FileCheck %s --check-prefix=NOOBJNODEMANGLE
# CHECK-NOT: error: could not get the buffer for the member defining
# ERR-NOT: error: could not get the buffer for the member defining
# NOOBJ: error: could not get the buffer for the member defining symbol int __cdecl f(void): {{.*}}.lib({{.*}}.lib.obj):
# NOOBJWHOLE: error: {{.*}}.lib: could not get the buffer for a child of the archive: '{{.*}}.obj'
# NOOBJNODEMANGLE: error: could not get the buffer for the member defining symbol ?f@@YAHXZ: {{.*}}.lib({{.*}}.lib.obj):
.text