[LLD][COFF] Add index to disambiguate archive members when using -wholearchive

Patch by Markus Böck.

PR42951: When linking an archive with members that have the same name linking
fails when using the -wholearchive option. This patch passes the index
of the member in the archive to the offset parameter to disambiguate the
member.

Differential Revision: https://reviews.llvm.org/D66239

llvm-svn: 371509

Author: rui314

lld/COFF/Driver.cpp

@@ -188,8 +188,9 @@ void LinkerDriver::addBuffer(std::unique_ptr<MemoryBuffer> mb,
       Archive *archive = file.get();
       make<std::unique_ptr<Archive>>(std::move(file)); // take ownership
 
+      int memberIndex = 0;
       for (MemoryBufferRef m : getArchiveMembers(archive))
-        addArchiveBuffer(m, "<whole-archive>", filename, 0);
+        addArchiveBuffer(m, "<whole-archive>", filename, memberIndex++);
       return;
     }
     symtab->addFile(make<ArchiveFile>(mbref));

lld/test/COFF/thinlto-whole-archives.ll

@@ -0,0 +1,30 @@
+; REQUIRES: x86
+; RUN: rm -fr %T/thinlto-whole-archives
+; RUN: mkdir %T/thinlto-whole-archives %T/thinlto-whole-archives/a %T/thinlto-whole-archives/b
+; RUN: opt -thinlto-bc -o %T/thinlto-whole-archives/main.obj %s
+; RUN: opt -thinlto-bc -o %T/thinlto-whole-archives/a/bar.obj %S/Inputs/lto-dep.ll
+; RUN: opt -thinlto-bc -o %T/thinlto-whole-archives/b/bar.obj %S/Inputs/bar.ll
+; RUN: llvm-ar crs %T/thinlto-whole-archives/a.lib %T/thinlto-whole-archives/a/bar.obj %T/thinlto-whole-archives/b/bar.obj
+; RUN: lld-link -out:%T/thinlto-whole-archives/main.exe -entry:main \
+; RUN:     -wholearchive -lldsavetemps -subsystem:console %T/thinlto-whole-archives/main.obj \
+; RUN:     %T/thinlto-whole-archives/a.lib
+; RUN: FileCheck %s < %T/thinlto-whole-archives/main.exe.resolution.txt
+
+; CHECK: {{[/\\]thinlto-whole-archives[/\\]main.obj$}}
+; CHECK: {{^-r=.*[/\\]thinlto-whole-archives[/\\]main.obj,main,px$}}
+; CHECK: {{[/\\]thinlto-whole-archives[/\\]a.libbar.obj[0-9]+$}}
+; CHECK-NEXT: {{^-r=.*[/\\]thinlto-whole-archives[/\\]a.libbar.obj[0-9]+,foo,p$}}
+; CHECK-NEXT: {{[/\\]thinlto-whole-archives[/\\]a.libbar.obj[0-9]+$}}
+; CHECK-NEXT: {{^-r=.*[/\\]thinlto-whole-archives[/\\]a.libbar.obj[0-9]+,bar,p$}}
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+declare void @bar()
+declare void @foo()
+
+define i32 @main() {
+  call void @foo()
+  call void @bar()
+  ret i32 0
+}