[ThinLTO] Internalize readonly globals

An attempt to recommit r346584 after failure on OSX build bot.
Fixed cache key computation in ThinLTOCodeGenerator and added
test case

llvm-svn: 347033

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/ThinLTO/X86/index-const-prop-gvref.ll b/llvm/test/ThinLTO/X86/index-const-prop-gvref.ll
new file mode 100644
index 00000000000..87103fee141
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/index-const-prop-gvref.ll
@@ -0,0 +1,27 @@
+; RUN: opt -module-summary %s -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/index-const-prop-gvref.ll -o %t2.bc
+; RUN: llvm-lto2 run -save-temps %t2.bc -r=%t2.bc,b,pl -r=%t2.bc,a,pl \
+; RUN:               %t1.bc -r=%t1.bc,main,plx -r=%t1.bc,a, -r=%t1.bc,b, -o %t3
+; RUN: llvm-dis %t3.1.3.import.bc -o - | FileCheck %s --check-prefix=SRC
+; RUN: llvm-dis %t3.2.3.import.bc -o - | FileCheck %s --check-prefix=DEST
+
+; No variable in the source module should have been internalized
+; SRC:      @b = dso_local global i32* @a
+; SRC-NEXT: @a = dso_local global i32 42
+
+; We can't internalize globals referenced by other live globals
+; DEST:      @b = external dso_local global i32*
+; DEST-NEXT: @a = available_externally dso_local global i32 42, align 4
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@a = external global i32
+@b = external global i32*
+
+define i32 @main() {
+  %p = load i32*, i32** @b, align 8  
+  store i32 33, i32* %p, align 4
+  %v = load i32, i32* @a, align 4
+  ret i32 %v
+}