ThinLTO/ModuleLinker: add a flag to not always pull-in linkonce when performing importing

Summary:
The function importer already decided what symbols need to be pulled
in. Also these magically added ones will not be in the export list
for the source module, which can confuse the internalizer for
instance.

Reviewers: tejohnson, rafael

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D19096

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266948

2 files changed, 57 insertions, 3 deletions

diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
index 79b766b386d..03ea3647fd7 100644
--- a/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport.ll
@@ -99,4 +99,46 @@ entry:
   ret void
 }
 
+define void @referencelargelinkonce() #0 {
+entry:
+  call void @linkonceodr()
+  ret void
+}
+
+; A large enough linkonce_odr function that should never be imported
+define linkonce_odr void @linkonceodr() #0 {
+entry:
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  call void @globalfunc2()
+  ret void
+}
+
 
diff --git a/llvm/test/Transforms/FunctionImport/funcimport.ll b/llvm/test/Transforms/FunctionImport/funcimport.ll
index 8e059ca59a7..f0df3200555 100644
--- a/llvm/test/Transforms/FunctionImport/funcimport.ll
+++ b/llvm/test/Transforms/FunctionImport/funcimport.ll
@@ -4,14 +4,19 @@
 ; RUN: llvm-lto -thinlto -print-summary-global-ids -o %t3 %t.bc %t2.bc 2>&1 | FileCheck %s --check-prefix=GUID
 
 ; Do the import now
-; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIMDEF
+; RUN: opt -disable-force-link-odr -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIMDEF
 ; "-stats" requires +Asserts.
 ; REQUIRES: asserts
 
 ; Test import with smaller instruction limit
-; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIM5
+; RUN: opt -disable-force-link-odr -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=CHECK --check-prefix=INSTLIM5
 ; INSTLIM5-NOT: @staticfunc.llvm.
 
+; Test import with smaller instruction limit and without the -disable-force-link-odr
+; RUN: opt -function-import -summary-file %t3.thinlto.bc %t.bc -import-instr-limit=5 -S | FileCheck %s --check-prefix=INSTLIM5ODR
+; INSTLIM5ODR: define linkonce_odr void @linkonceodr()
+
+
 define i32 @main() #0 {
 entry:
   call void (...) @weakalias()
@@ -23,6 +28,7 @@ entry:
   call void (...) @setfuncptr()
   call void (...) @callfuncptr()
   call void (...) @weakfunc()
+  call void (...) @referencelargelinkonce()
   ret i32 0
 }
 
@@ -78,6 +84,12 @@ declare void @callfuncptr(...) #1
 ; CHECK-DAG: %0 = load void ()*, void ()** @P.llvm.
 ; CHECK-DAG: store void ()* @staticfunc2.llvm.{{.*}}, void ()** @P.llvm.
 
+; Ensure that @referencelargelinkonce definition is pulled in, but later we
+; also check that the linkonceodr function is not.
+; CHECK-DAG: define available_externally void @referencelargelinkonce()
+; INSTLIM5-DAG: declare void @linkonceodr()
+declare void @referencelargelinkonce(...)
+
 ; Won't import weak func
 ; CHECK-DAG: declare void @weakfunc(...)
 declare void @weakfunc(...) #1
@@ -87,7 +99,7 @@ declare void @weakfunc(...) #1
 ; INSTLIM5-DAG: declare hidden void @funcwithpersonality.llvm.{{.*}}()
 
 ; INSTLIMDEF-DAG: Import globalfunc2
-; INSTLIMDEF-DAG: 11 function-import - Number of functions imported
+; INSTLIMDEF-DAG: 13 function-import - Number of functions imported
 
 ; The actual GUID values will depend on path to test.
 ; GUID-DAG: GUID {{.*}} is weakalias