[LTO][ThinLTO] Use the linker resolutions to mark global values as dso_local.

Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.

Differential Revision: https://reviews.llvm.org/D35702

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317374 91177308-0d34-0410-b5e6-96231b3b80d8

test/Bitcode/thinlto-summary-local-5.0.ll

@@ -0,0 +1,22 @@
+; Bitcode compatibility test for dso_local flag in thin-lto summaries.
+; Checks that older bitcode summaries without the dso_local op are still
+; properly parsed and don't set GlobalValues as dso_local.
+
+; RUN: llvm-dis < %s.bc | FileCheck %s
+; RUN: llvm-bcanalyzer -dump %s.bc | FileCheck %s --check-prefix=BCAN
+
+define void @foo() {
+;CHECK-DAG:define void @foo()
+      ret void
+}
+
+@bar = global i32 0
+;CHECK-DAG: @bar = global i32 0
+
+@baz = alias i32, i32* @bar
+;CHECK-DAG: @bar = global i32 0
+
+;BCAN: <SOURCE_FILENAME
+;BCAN-NEXT: <GLOBALVAR {{.*}} op7=0/>
+;BCAN-NEXT: <FUNCTION {{.*}} op16=0/>
+;BCAN-NEXT: <ALIAS {{.*}} op9=0/>