Restore with fix "[ThinLTO] Ensure we always select the same function copy to import"

This restores r308078/r308079 with a fix for bot non-determinisim (make
sure we run llvm-lto in single threaded mode so the debug output doesn't get
interleaved).

llvm-svn: 308114

3 files changed, 86 insertions, 0 deletions

diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved1.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved1.ll
new file mode 100644
index 00000000000..2b2443c96af
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved1.ll
@@ -0,0 +1,34 @@
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+define void @foo() {
+  call void @linkonceodrfunc()
+  call void @linkonceodrfunc2()
+  ret void
+}
+
+define linkonce_odr void @linkonceodrfunc() {
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  ret void
+}
+
+define linkonce_odr void @linkonceodrfunc2() {
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  ret void
+}
+
+define internal void @f() {
+  ret void
+}
diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved2.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved2.ll
new file mode 100644
index 00000000000..278a7f4553f
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_resolved2.ll
@@ -0,0 +1,6 @@
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+define linkonce_odr void @linkonceodrfunc() {
+  ret void
+}
diff --git a/llvm/test/Transforms/FunctionImport/funcimport_resolved.ll b/llvm/test/Transforms/FunctionImport/funcimport_resolved.ll
new file mode 100644
index 00000000000..1d39a5a72a5
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/funcimport_resolved.ll
@@ -0,0 +1,46 @@
+; Test to ensure that we always select the same copy of a linkonce function
+; when it is encountered with different thresholds. Initially, we will encounter
+; the copy in funcimport_resolved1.ll with a lower threshold by reaching it
+; from the deeper call chain via foo(), and it won't be selected for importing.
+; Later we encounter it with a higher threshold via the direct call from main()
+; and it will be selected. We don't want to select both the copy from
+; funcimport_resolved1.ll and the smaller one from funcimport_resolved2.ll,
+; leaving it up to the backend to figure out which one to actually import.
+; The linkonce_odr may have different instruction counts in practice due to
+; different inlines in the compile step.
+
+; Require asserts so we can use -debug-only
+; REQUIRES: asserts
+
+; RUN: opt -module-summary %s -o %t.bc
+; RUN: opt -module-summary %p/Inputs/funcimport_resolved1.ll -o %t2.bc
+; RUN: opt -module-summary %p/Inputs/funcimport_resolved2.ll -o %t3.bc
+
+; First do a sanity check that all callees are imported with the default
+; instruction limit
+; RUN: llvm-lto2 run %t.bc %t2.bc %t3.bc -o %t4 -r=%t.bc,_main,pl -r=%t.bc,_linkonceodrfunc,l -r=%t.bc,_foo,l -r=%t2.bc,_foo,pl -r=%t2.bc,_linkonceodrfunc,pl -r=%t2.bc,_linkonceodrfunc2,pl -r=%t3.bc,_linkonceodrfunc,l -thinlto-threads=1 -debug-only=function-import 2>&1 | FileCheck %s --check-prefix=INSTLIMDEFAULT
+; INSTLIMDEFAULT-DAG: Is importing function {{.*}} foo from {{.*}}funcimport_resolved1.ll
+; INSTLIMDEFAULT-DAG: Is importing function {{.*}} linkonceodrfunc from {{.*}}funcimport_resolved1.ll
+; INSTLIMDEFAULT-DAG: Is importing function {{.*}} linkonceodrfunc2 from {{.*}}funcimport_resolved1.ll
+; INSTLIMDEFAULT-DAG: Is importing function {{.*}} f from {{.*}}funcimport_resolved1.ll
+
+; Now run with the lower threshold that will only allow linkonceodrfunc to be
+; imported from funcimport_resolved1.ll the second time it is encountered.
+; RUN: llvm-lto2 run %t.bc %t2.bc %t3.bc -o %t4 -r=%t.bc,_main,pl -r=%t.bc,_linkonceodrfunc,l -r=%t.bc,_foo,l -r=%t2.bc,_foo,pl -r=%t2.bc,_linkonceodrfunc,pl -r=%t2.bc,_linkonceodrfunc2,pl -r=%t3.bc,_linkonceodrfunc,l -thinlto-threads=1 -debug-only=function-import -import-instr-limit=8 2>&1 | FileCheck %s --check-prefix=INSTLIM8
+; INSTLIM8-DAG: Is importing function {{.*}} foo from {{.*}}funcimport_resolved1.ll
+; INSTLIM8-DAG: Is importing function {{.*}} linkonceodrfunc from {{.*}}funcimport_resolved1.ll
+; INSTLIM8-DAG: Not importing function {{.*}} linkonceodrfunc2 from {{.*}}funcimport_resolved1.ll
+; INSTLIM8-DAG: Is importing function {{.*}} f from {{.*}}funcimport_resolved1.ll
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+define i32 @main() #0 {
+entry:
+  call void (...) @foo()
+  call void (...) @linkonceodrfunc()
+  ret i32 0
+}
+
+declare void @foo(...) #1
+declare void @linkonceodrfunc(...) #1