This revision was automatically updated to reflect the committed changes.
Closed by commit rC325411: [ThinLTO] Allow indexing to request backend to
ignore the module (authored by vitalybuka, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D42995?vs=134657&id=134755#toc
Repository:
rC Clang
https://reviews.llvm.org/D42995
Files:
lib/CodeGen/BackendUtil.cpp
test/CodeGen/Inputs/thinlto-distributed-backend-skip.bc
test/CodeGen/thinlto-distributed-backend-skip.ll
Index: test/CodeGen/thinlto-distributed-backend-skip.ll
===================================================================
--- test/CodeGen/thinlto-distributed-backend-skip.ll
+++ test/CodeGen/thinlto-distributed-backend-skip.ll
@@ -0,0 +1,21 @@
+; REQUIRES: x86-registered-target
+
+; Check that ThinLTO backend respects "SkipModuleByDistributedBackend"
+; flag which can be set by indexing.
+
+; RUN: opt -thinlto-bc -o %t.o %s
+
+; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu \
+; RUN: -fthinlto-index=%S/Inputs/thinlto-distributed-backend-skip.bc \
+; RUN: -emit-llvm -o - -x ir %t.o | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-grtev4-linux-gnu"
+
+; CHECK: "empty"
+; CHECK: target triple =
+; CHECK-NOT: @main
+define i32 @main() {
+entry:
+ ret i32 0
+}
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -1153,6 +1153,7 @@
const llvm::DataLayout &TDesc, Module *M,
BackendAction Action,
std::unique_ptr<raw_pwrite_stream> OS) {
+ std::unique_ptr<llvm::Module> EmptyModule;
if (!CGOpts.ThinLTOIndexFile.empty()) {
// If we are performing a ThinLTO importing compile, load the function
index
// into memory and pass it into runThinLTOBackend, which will run the
@@ -1170,11 +1171,22 @@
// A null CombinedIndex means we should skip ThinLTO compilation
// (LLVM will optionally ignore empty index files, returning null instead
// of an error).
- bool DoThinLTOBackend = CombinedIndex != nullptr;
- if (DoThinLTOBackend) {
- runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
- LOpts, std::move(OS), CGOpts.SampleProfileFile,
Action);
- return;
+ if (CombinedIndex) {
+ if (!CombinedIndex->skipModuleByDistributedBackend()) {
+ runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
+ LOpts, std::move(OS), CGOpts.SampleProfileFile,
+ Action);
+ return;
+ }
+ // Distributed indexing detected that nothing from the module is needed
+ // for the final linking. So we can skip the compilation. We sill need to
+ // output an empty object file to make sure that a linker does not fail
+ // trying to read it. Also for some features, like CFI, we must skip
+ // the compilation as CombinedIndex does not contain all required
+ // information.
+ EmptyModule = llvm::make_unique<llvm::Module>("empty", M->getContext());
+ EmptyModule->setTargetTriple(M->getTargetTriple());
+ M = EmptyModule.get();
}
}
Index: test/CodeGen/thinlto-distributed-backend-skip.ll
===================================================================
--- test/CodeGen/thinlto-distributed-backend-skip.ll
+++ test/CodeGen/thinlto-distributed-backend-skip.ll
@@ -0,0 +1,21 @@
+; REQUIRES: x86-registered-target
+
+; Check that ThinLTO backend respects "SkipModuleByDistributedBackend"
+; flag which can be set by indexing.
+
+; RUN: opt -thinlto-bc -o %t.o %s
+
+; RUN: %clang_cc1 -triple x86_64-grtev4-linux-gnu \
+; RUN: -fthinlto-index=%S/Inputs/thinlto-distributed-backend-skip.bc \
+; RUN: -emit-llvm -o - -x ir %t.o | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-grtev4-linux-gnu"
+
+; CHECK: "empty"
+; CHECK: target triple =
+; CHECK-NOT: @main
+define i32 @main() {
+entry:
+ ret i32 0
+}
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -1153,6 +1153,7 @@
const llvm::DataLayout &TDesc, Module *M,
BackendAction Action,
std::unique_ptr<raw_pwrite_stream> OS) {
+ std::unique_ptr<llvm::Module> EmptyModule;
if (!CGOpts.ThinLTOIndexFile.empty()) {
// If we are performing a ThinLTO importing compile, load the function index
// into memory and pass it into runThinLTOBackend, which will run the
@@ -1170,11 +1171,22 @@
// A null CombinedIndex means we should skip ThinLTO compilation
// (LLVM will optionally ignore empty index files, returning null instead
// of an error).
- bool DoThinLTOBackend = CombinedIndex != nullptr;
- if (DoThinLTOBackend) {
- runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
- LOpts, std::move(OS), CGOpts.SampleProfileFile, Action);
- return;
+ if (CombinedIndex) {
+ if (!CombinedIndex->skipModuleByDistributedBackend()) {
+ runThinLTOBackend(CombinedIndex.get(), M, HeaderOpts, CGOpts, TOpts,
+ LOpts, std::move(OS), CGOpts.SampleProfileFile,
+ Action);
+ return;
+ }
+ // Distributed indexing detected that nothing from the module is needed
+ // for the final linking. So we can skip the compilation. We sill need to
+ // output an empty object file to make sure that a linker does not fail
+ // trying to read it. Also for some features, like CFI, we must skip
+ // the compilation as CombinedIndex does not contain all required
+ // information.
+ EmptyModule = llvm::make_unique<llvm::Module>("empty", M->getContext());
+ EmptyModule->setTargetTriple(M->getTargetTriple());
+ M = EmptyModule.get();
}
}
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