[LLD][ELF] Use offset in thin archives to disambiguate thinLTO members

This is fixing a thinLTO module collision issue for thin archives. The problem is that we always use a zero offset to name members in a thin archive and that causes the following build error:

    ld.lld: error: Expected at most one ThinLTO module per bitcode file

which happens to a thin archive that has two members with the same object file name (whose paths will be ignored by thinLTO driver)

The fix here is to use real member offset instead as is done for non-thin archives.

Differential Revision: https://reviews.llvm.org/D79880

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 7facee3..7a165e2 100644 (file)
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -1162,8 +1162,7 @@ void ArchiveFile::fetch(const Archive::Symbol &sym) {
   if (tar && c.getParent()->isThin())
     tar->append(relativeToRoot(CHECK(c.getFullName(), this)), mb.getBuffer());
 
-  InputFile *file = createObjectFile(
-      mb, getName(), c.getParent()->isThin() ? 0 : c.getChildOffset());
+  InputFile *file = createObjectFile(mb, getName(), c.getChildOffset());
   file->groupId = groupId;
   parseFile(file);
 }

diff --git a/lld/test/ELF/lto/thinlto-thin-archive-collision.ll b/lld/test/ELF/lto/thinlto-thin-archive-collision.ll
new file mode 100644 (file)
index 0000000..1a175f2
--- /dev/null
+++ b/lld/test/ELF/lto/thinlto-thin-archive-collision.ll
@@ -0,0 +1,27 @@
+; REQUIRES: x86
+; RUN: rm -fr %t && mkdir %t && cd %t
+; RUN: mkdir thinlto-archives thinlto-archives/a thinlto-archives/b
+; RUN: opt -thinlto-bc -o thinlto-archives/main.o %s
+; RUN: opt -thinlto-bc -o thinlto-archives/a/thin.o %S/Inputs/thin1.ll
+; RUN: opt -thinlto-bc -o thinlto-archives/b/thin.o %S/Inputs/thin2.ll
+; RUN: llvm-ar qcT thinlto-archives/thin.a thinlto-archives/a/thin.o thinlto-archives/b/thin.o
+; RUN: ld.lld thinlto-archives/main.o thinlto-archives/thin.a -o thinlto-archives/main.exe --save-temps
+; RUN: FileCheck %s < thinlto-archives/main.exe.resolution.txt
+
+; CHECK: thinlto-archives/main.o
+; CHECK: thinlto-archives/thin.a(thin.o at {{[1-9][0-9]+}})
+; CHECK-NEXT: -r=thinlto-archives/thin.a(thin.o at {{[1-9][0-9]+}}),foo,pl
+; CHECK: thinlto-archives/thin.a(thin.o at {{[1-9][0-9]+}})
+; CHECK-NEXT: -r=thinlto-archives/thin.a(thin.o at {{[1-9][0-9]+}}),blah,pl
+
+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-scei-ps4"
+
+declare i32 @blah(i32 %meh)
+declare i32 @foo(i32 %goo)
+
+define i32 @_start() {
+  call i32 @foo(i32 0)
+  call i32 @blah(i32 0)
+  ret i32 0
+}

diff --git a/lld/test/ELF/lto/thinlto.ll b/lld/test/ELF/lto/thinlto.ll
index 918f6ff..5d5df64 100644 (file)
--- a/lld/test/ELF/lto/thinlto.ll
+++ b/lld/test/ELF/lto/thinlto.ll
@@ -62,7 +62,7 @@
 ; 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 %t.null
-; RUN: ls '%t.dir/t.a(t.o at 0).0.preopt.bc'
+; RUN: ls %t.dir/t.a*.0.preopt.bc
 
 ; NM1: T f
 ; NM2: T g