[ThinLTO] Add an option to force summary call edges cold for debugging

Summary:
Useful to selectively disable importing into specific modules for
debugging/triaging/workarounds.

Reviewers: eraman

Subscribers: inglorion, llvm-commits

Differential Revision: https://reviews.llvm.org/D45062

llvm-svn: 328909

3 files changed, 77 insertions, 0 deletions

diff --git a/llvm/test/Transforms/FunctionImport/Inputs/funcimport_forcecold.ll b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_forcecold.ll
new file mode 100644
index 00000000000..a59d68c1e18
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/Inputs/funcimport_forcecold.ll
@@ -0,0 +1,4 @@
+define void @foo() {
+entry:
+  ret void
+}
diff --git a/llvm/test/Transforms/FunctionImport/funcimport_forcecold.ll b/llvm/test/Transforms/FunctionImport/funcimport_forcecold.ll
new file mode 100644
index 00000000000..a9aa77f9afe
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/funcimport_forcecold.ll
@@ -0,0 +1,36 @@
+; Test to ensure that building summary with -force-summary-edges-cold
+; blocks importing as expected.
+
+; "-stats" and "-debug-only" require +Asserts.
+; REQUIRES: asserts
+
+; First do with default options, which should import
+; RUN: opt -module-summary %s -o %t.bc
+; RUN: opt -module-summary %p/Inputs/funcimport_forcecold.ll -o %t2.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=IMPORT
+
+; Next rebuild caller module summary with non-critical edges forced cold (which
+; should affect all edges in this test as we don't have any sample pgo).
+; Make sure we don't import.
+; RUN: opt -force-summary-edges-cold=all-non-critical -module-summary %s -o %t.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=NOIMPORT
+
+; Next rebuild caller module summary with all edges forced cold.
+; Make sure we don't import.
+; RUN: opt -force-summary-edges-cold=all -module-summary %s -o %t.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=NOIMPORT
+
+define i32 @main() {
+entry:
+  call void @foo()
+  ret i32 0
+}
+
+; IMPORT: Import foo
+; NOIMPORT-NOT: Import foo
+; IMPORT: define available_externally void @foo()
+; NOIMPORT: declare void @foo()
+declare void @foo()
diff --git a/llvm/test/Transforms/FunctionImport/funcimport_forcecold_samplepgo.ll b/llvm/test/Transforms/FunctionImport/funcimport_forcecold_samplepgo.ll
new file mode 100644
index 00000000000..4ff02b9ba0f
--- /dev/null
+++ b/llvm/test/Transforms/FunctionImport/funcimport_forcecold_samplepgo.ll
@@ -0,0 +1,37 @@
+; Test to ensure that building summary with -force-summary-edges-cold
+; blocks importing as expected.
+
+; "-stats" and "-debug-only" require +Asserts.
+; REQUIRES: asserts
+
+; First do with default options, which should import
+; RUN: opt -module-summary %s -o %t.bc
+; RUN: opt -module-summary %p/Inputs/funcimport_forcecold.ll -o %t2.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=IMPORT
+
+; Next rebuild caller module summary with only non-critical edges forced cold,
+; which should still import in this case.
+; RUN: opt -force-summary-edges-cold=all-non-critical -module-summary %s -o %t.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=IMPORT
+
+; Next rebuild caller module summary with all edges forced cold.
+; Make sure we don't import.
+; RUN: opt -force-summary-edges-cold=all -module-summary %s -o %t.bc
+; RUN: llvm-lto -thinlto -o %t3 %t.bc %t2.bc
+; RUN: opt -function-import -stats -print-imports -summary-file %t3.thinlto.bc %t.bc -S 2>&1 | FileCheck %s --check-prefix=NOIMPORT
+
+define i32 @main() !prof !1 {
+entry:
+  call void @foo()
+  ret i32 0
+}
+
+; IMPORT: Import foo
+; NOIMPORT-NOT: Import foo
+; IMPORT: define available_externally void @foo()
+; NOIMPORT: declare void @foo()
+declare void @foo()
+
+!1 = !{!"function_entry_count", i64 110, i64 6699318081062747564}