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[llvm-link] fix linker behavior when linking archives with --only-needed option 

This patch fixes linker behavior when archive is linked with other inputs
as a library (i.e. when --only-needed option is specified). In this case library
is expected to be normally linked first into a separate module and only after
that linker should import required symbols from the linked library module.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D92535
This commit is contained in:
Sergey Dmitriev 2021-01-05 09:46:55 -08:00
parent a427f15d60
commit 761aca1e2e
3 changed files with 28 additions and 7 deletions
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8
llvm/test/tools/llvm-link/Inputs/i.ll Normal file
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@ -0,0 +1,8 @@
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
define void @i() {
call void @f()
ret void
}
declare void @f()

15
llvm/test/tools/llvm-link/archive-only-needed.ll Normal file
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@ -0,0 +1,15 @@
; RUN: llvm-as %S/Inputs/f.ll -o %t.f.bc
; RUN: llvm-as %S/Inputs/g.ll -o %t.g.bc
; RUN: llvm-as %S/Inputs/i.ll -o %t.i.bc
; RUN: rm -f %t.lib
; RUN: llvm-ar cr %t.lib %t.f.bc %t.g.bc %t.i.bc
; RUN: llvm-link %s %t.lib -o %t.linked.bc --only-needed
; RUN: llvm-nm %t.linked.bc | FileCheck %s
; CHECK: -------- T f
; CHECK: -------- T i
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@i = external global i8*
@llvm.used = appending global [1 x i8*] [i8* bitcast (i8** @i to i8*)], section "llvm.metadata"

12
llvm/tools/llvm-link/llvm-link.cpp
View File

@ -142,9 +142,9 @@ static std::unique_ptr<Module> loadFile(const char *argv0,
return Result; return Result;
} }
static std::unique_ptr<Module> static std::unique_ptr<Module> loadArFile(const char *Argv0,
loadArFile(const char *Argv0, std::unique_ptr<MemoryBuffer> Buffer, std::unique_ptr<MemoryBuffer> Buffer,
LLVMContext &Context, unsigned OrigFlags, unsigned ApplicableFlags) { LLVMContext &Context) {
std::unique_ptr<Module> Result(new Module("ArchiveModule", Context)); std::unique_ptr<Module> Result(new Module("ArchiveModule", Context));
StringRef ArchiveName = Buffer->getBufferIdentifier(); StringRef ArchiveName = Buffer->getBufferIdentifier();
if (Verbose) if (Verbose)
@ -197,9 +197,8 @@ loadArFile(const char *Argv0, std::unique_ptr<MemoryBuffer> Buffer,
} }
if (Verbose) if (Verbose)
errs() << "Linking member '" << ChildName << "' of archive library.\n"; errs() << "Linking member '" << ChildName << "' of archive library.\n";
if (Linker::linkModules(*Result, std::move(M), ApplicableFlags)) if (Linker::linkModules(*Result, std::move(M)))
return nullptr; return nullptr;
ApplicableFlags = OrigFlags;
} // end for each child } // end for each child
ExitOnErr(std::move(Err)); ExitOnErr(std::move(Err));
return Result; return Result;
@ -354,8 +353,7 @@ static bool linkFiles(const char *argv0, LLVMContext &Context, Linker &L,
std::unique_ptr<Module> M = std::unique_ptr<Module> M =
identify_magic(Buffer->getBuffer()) == file_magic::archive identify_magic(Buffer->getBuffer()) == file_magic::archive
? loadArFile(argv0, std::move(Buffer), Context, Flags, ? loadArFile(argv0, std::move(Buffer), Context)
ApplicableFlags)
: loadFile(argv0, std::move(Buffer), Context); : loadFile(argv0, std::move(Buffer), Context);
if (!M.get()) { if (!M.get()) {
errs() << argv0 << ": "; errs() << argv0 << ": ";