Reland r313157, "ThinLTO: Correctly follow aliasee references when dead stripping." which was reverted in r313222.

This reland includes a fix for the LowerTypeTests pass so that it
looks past aliases when determining which type identifiers are live.

Differential Revision: https://reviews.llvm.org/D37842

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313229 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 36 insertions, 1 deletions

diff --git a/test/LTO/Resolution/X86/Inputs/dead-strip-alias.ll b/test/LTO/Resolution/X86/Inputs/dead-strip-alias.ll
new file mode 100644
index 00000000000..16154d2c45b
--- /dev/null
+++ b/test/LTO/Resolution/X86/Inputs/dead-strip-alias.ll
@@ -0,0 +1,4 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@external = global i8 42
diff --git a/test/LTO/Resolution/X86/dead-strip-alias.ll b/test/LTO/Resolution/X86/dead-strip-alias.ll
new file mode 100644
index 00000000000..d009a484e4f
--- /dev/null
+++ b/test/LTO/Resolution/X86/dead-strip-alias.ll
@@ -0,0 +1,20 @@
+; RUN: opt -module-summary -o %t %s
+; RUN: opt -module-summary -o %t2 %S/Inputs/dead-strip-alias.ll
+; RUN: llvm-lto2 run %t -r %t,main,px -r %t,alias,p -r %t,external, \
+; RUN:               %t2 -r %t2,external,p \
+; RUN: -save-temps -o %t3
+; RUN: llvm-nm %t3.1 | FileCheck %s
+
+; CHECK: D external
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@alias = alias i8*, i8** @internal
+
+@internal = internal global i8* @external
+@external = external global i8
+
+define i8** @main() {
+  ret i8** @alias
+}
diff --git a/test/LTO/Resolution/X86/lowertypetests.ll b/test/LTO/Resolution/X86/lowertypetests.ll
index c84a786e66f..b87452c8e7a 100644
--- a/test/LTO/Resolution/X86/lowertypetests.ll
+++ b/test/LTO/Resolution/X86/lowertypetests.ll
@@ -1,21 +1,32 @@
 ; RUN: opt -thinlto-bc -o %t %s
-; RUN: llvm-lto2 run -r %t,f,plx -r %t,foo,lx -r %t,foo,plx -o %t1 %t
+; RUN: llvm-lto2 run -r %t,f,plx -r %t,g_alias,plx -r %t,foo,lx -r %t,foo,plx -r %t,bar,lx -r %t,bar,plx -o %t1 %t
 ; RUN: llvm-nm %t1.0 | FileCheck --check-prefix=MERGED %s
 ; RUN: llvm-nm %t1.1 | FileCheck %s
 
+; MERGED: R __typeid_bar_global_addr
 ; MERGED: R __typeid_foo_global_addr
+; CHECK: U __typeid_bar_global_addr
 ; CHECK: U __typeid_foo_global_addr
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @foo = global i32 0, !type !0
+@bar = global i32 0, !type !1
 
 define i1 @f(i8* %ptr) {
   %p = call i1 @llvm.type.test(i8* %ptr, metadata !"foo")
   ret i1 %p
 }
 
+@g_alias = alias i1 (i8*), i1 (i8*)* @g
+
+define internal i1 @g(i8* %ptr) {
+  %p = call i1 @llvm.type.test(i8* %ptr, metadata !"bar")
+  ret i1 %p
+}
+
 declare i1 @llvm.type.test(i8* %ptr, metadata %typeid) nounwind readnone
 
 !0 = !{i32 0, !"foo"}
+!1 = !{i32 0, !"bar"}