[lld][ELF][COFF] Fix archived bitcode files naming

[evgeny777]

Summary

This makes LTO -save-temps usable when archive contains full path to file.

[MaskRay]

lld/test/ELF/lto/thinlto.ll

26

Enhance the test to check one of the produced temporary files.

; RUN: rm -fr %t.dir
; RUN: mkdir -p %t.dir
; RUN: cp %t2.o %t.dir/t.o
; RUN: llvm-ar rcsT %t.dir/t.a %t.dir/t.o
; RUN: ld.lld -save-temps %t1.o %t.dir/t.a -o - > /dev/null
; RUN: ls '%t.dir/t.a(t.o at 0).0.preopt.bc'

The last line makes it clear the indented filename.

[MaskRay]

For the title:

Fix archived bitcode files naming

Suggested: Support -save-temps for thin archives.

The thin archive is a GNU extension. Otherwise there is no POSIX requirement to support a full path for a member. So this is not a bug.

[evgeny777]

Suggested: Support -save-temps for thin archives.

Windows libraries are not thin archives, but still contain full paths to member objects. Without this patch /lldsavetemps is almost unusable for thin LTO clang/LLVM builds on Windows.

[evgeny777]

Added check for temp file

lld/COFF/InputFiles.cpp

BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
   // ThinLTO assumes that all MemoryBufferRefs given to it have a unique
   // name. If two archives define two members with the same name, this
   // causes a collision which result in only one of the objects being taken
   // into consideration at LTO time (which very likely causes undefined
   // symbols later in the link stage). So we append file offset to make
   // filename unique.
   MemoryBufferRef mbref(
       mb.getBuffer(),
-      saver.save(archiveName + path +
-                 (archiveName.empty() ? "" : utostr(offsetInArchive))));
+      saver.save(archiveName.empty() ? path
+                                     : archiveName + sys::path::filename(path) +
+                                           utostr(offsetInArchive)));
 
   obj = check(lto::InputFile::create(mbref));
 }
 
 BitcodeFile::~BitcodeFile() = default;
 
 void BitcodeFile::parse() {
   std::vector<std::pair<Symbol *, bool>> comdat(obj->getComdatTable().size());

lld/ELF/InputFiles.cpp

if (config->thinLTOIndexOnly)
     path = replaceThinLTOSuffix(mb.getBufferIdentifier());
 
   // ThinLTO assumes that all MemoryBufferRefs given to it have a unique
   // name. If two archives define two members with the same name, this
   // causes a collision which result in only one of the objects being taken
   // into consideration at LTO time (which very likely causes undefined
   // symbols later in the link stage). So we append file offset to make
   // filename unique.
-  StringRef name = archiveName.empty()
-                       ? saver.save(path)
-                       : saver.save(archiveName + "(" + path + " at " +
-                                    utostr(offsetInArchive) + ")");
+  StringRef name =
+      archiveName.empty()
+          : saver.save(archiveName + "(" + path::filename(path) + " at " +
   MemoryBufferRef mbref(mb.getBuffer(), name);
 
   obj = CHECK(lto::InputFile::create(mbref), this);
 
   Triple t(obj->getTargetTriple());
   ekind = getBitcodeELFKind(t);
   emachine = getBitcodeMachineKind(mb.getBufferIdentifier(), t);
 }

lld/test/COFF/thinlto.ll

 ; REQUIRES: x86
 ; RUN: rm -fr %T/thinlto
 ; RUN: mkdir %T/thinlto
 ; RUN: opt -thinlto-bc -o %T/thinlto/main.obj %s
 ; RUN: opt -thinlto-bc -o %T/thinlto/foo.obj %S/Inputs/lto-dep.ll
 ; RUN: lld-link /lldsavetemps /out:%T/thinlto/main.exe /entry:main /subsystem:console %T/thinlto/main.obj %T/thinlto/foo.obj
 ; RUN: llvm-nm %T/thinlto/main.exe1.lto.obj | FileCheck %s
 
+; This command will store full path to foo.obj in the archive %t.lib
+; Check that /lldsavetemps is still usable in such case.
+; RUN: lld-link /lib %T/thinlto/foo.obj /out:%t.lib
+; RUN: lld-link /lldsavetemps /out:%t.exe /entry:main /subsystem:console %T/thinlto/main.obj %t.lib
+; RUN: ls '%t.libfoo.obj230.0.preopt.bc'
+
 ; CHECK-NOT: U foo
 
 target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
 define i32 @main() {
   call void @foo()
   ret i32 0
 }
 
 declare void @foo()

lld/test/ELF/lto/thinlto.ll

 ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
 ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
 
 ; Then check without --thinlto-jobs (which currently default to hardware_concurrency)
 ; RUN: ld.lld -shared %t1.o %t2.o -o %t3
 ; RUN: llvm-nm %t31.lto.o | FileCheck %s --check-prefix=NM1
 ; RUN: llvm-nm %t32.lto.o | FileCheck %s --check-prefix=NM2
 
+; Check that -save-temps is usable with thin archives
+; RUN: rm -fr %t.dir
+; RUN: mkdir -p %t.dir
+; RUN: cp %t2.o %t.dir/t.o
+; RUN: llvm-ar rcsT %t.dir/t.a %t.dir/t.o
+; RUN: ld.lld -save-temps %t1.o %t.dir/t.a -o - > /dev/null
+; RUN: ls '%t.dir/t.a(t.o at 0).0.preopt.bc'
+
 ; NM1: T f
 ; NM2: T g
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 declare void @g(...)
 
 define void @f() {
 entry:
   call void (...) @g()
   ret void
 }