Bring r254336 back:
The difference is that now we don't error on out-of-comdat access to
internal global values. We copy them instead. This seems to match the
expectation of COFF linkers (see pr25686).
Original message:
Start deciding earlier what to link.
A traditional linker is roughly split in symbol resolution and
"copying
stuff".
The two tasks are badly mixed in lib/Linker.
This starts splitting them apart.
With this patch there are no direct call to linkGlobalValueBody or
linkGlobalValueProto. Everything is linked via WapValue.
This also includes a few fixes:
* A GV goes undefined if the comdat is dropped (comdat11.ll).
* We error if an internal GV goes undefined (comdat13.ll).
* We don't link an unused comdat.
The first two match the behavior of an ELF linker. The second one is
equivalent to running globaldce on the input.
llvm-svn: 254418
diff --git a/llvm/test/Linker/comdat11.ll b/llvm/test/Linker/comdat11.ll
new file mode 100644
index 0000000..dbade41
--- /dev/null
+++ b/llvm/test/Linker/comdat11.ll
@@ -0,0 +1,13 @@
+; RUN: llvm-link -S %s %p/Inputs/comdat11.ll -o - | FileCheck %s
+
+$foo = comdat any
+@foo = global i8 0, comdat
+
+; CHECK: @foo = global i8 0, comdat
+
+; CHECK: define void @zed() {
+; CHECK: call void @bar()
+; CHECK: ret void
+; CHECK: }
+
+; CHECK: declare void @bar()