[clang] 39016e3 - [C++20] [Modules] Don't import non-inline function bodies even if it is always-inline
Chuanqi Xu via cfe-commits
cfe-commits at lists.llvm.org
Mon Apr 15 22:07:09 PDT 2024
Author: Chuanqi Xu
Date: 2024-04-16T13:06:44+08:00
New Revision: 39016e33b0fe78ddb1f11822f71a8a233af4dca9
URL: https://github.com/llvm/llvm-project/commit/39016e33b0fe78ddb1f11822f71a8a233af4dca9
DIFF: https://github.com/llvm/llvm-project/commit/39016e33b0fe78ddb1f11822f71a8a233af4dca9.diff
LOG: [C++20] [Modules] Don't import non-inline function bodies even if it is always-inline
Recommit
https://github.com/llvm/llvm-project/commit/1ecbab56dcbb78268c8d19af34a50591f90b12a0
Close https://github.com/llvm/llvm-project/issues/80949
The new thing in this commit is to allow to import the function body
from instantiations if it is marked with always-inline. See the
discussion in https://github.com/llvm/llvm-project/issues/86893 for
details.
Added:
Modified:
clang/lib/CodeGen/CodeGenModule.cpp
clang/test/CodeGenCXX/module-funcs-from-imports.cppm
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index e44749672d5827..0c447b20cef40d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3952,9 +3952,20 @@ bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
// behavior may break ABI compatibility of the current unit.
if (const Module *M = F->getOwningModule();
M && M->getTopLevelModule()->isNamedModule() &&
- getContext().getCurrentNamedModule() != M->getTopLevelModule() &&
- !F->hasAttr<AlwaysInlineAttr>())
- return false;
+ getContext().getCurrentNamedModule() != M->getTopLevelModule()) {
+ // There are practices to mark template member function as always-inline
+ // and mark the template as extern explicit instantiation but not give
+ // the definition for member function. So we have to emit the function
+ // from explicitly instantiation with always-inline.
+ //
+ // See https://github.com/llvm/llvm-project/issues/86893 for details.
+ //
+ // TODO: Maybe it is better to give it a warning if we call a non-inline
+ // function from other module units which is marked as always-inline.
+ if (!F->isTemplateInstantiation() || !F->hasAttr<AlwaysInlineAttr>()) {
+ return false;
+ }
+ }
if (F->hasAttr<NoInlineAttr>())
return false;
diff --git a/clang/test/CodeGenCXX/module-funcs-from-imports.cppm b/clang/test/CodeGenCXX/module-funcs-from-imports.cppm
index 33cdf437110a9e..a2a9122fc39130 100644
--- a/clang/test/CodeGenCXX/module-funcs-from-imports.cppm
+++ b/clang/test/CodeGenCXX/module-funcs-from-imports.cppm
@@ -23,6 +23,21 @@ int func_in_gmf_not_called() {
return 44;
}
+template <class T>
+class A {
+public:
+ __attribute__((always_inline))
+ inline constexpr int getValue() {
+ return 43;
+ }
+
+ inline constexpr int getValue2() {
+ return 43;
+ }
+};
+
+extern template class A<char>;
+
//--- M.cppm
module;
#include "foo.h"
@@ -47,17 +62,21 @@ int always_inline_func() {
return 45;
}
+export using ::A;
+
//--- Use.cpp
import M;
int use() {
- return exported_func() + always_inline_func();
+ A<char> a;
+ return exported_func() + always_inline_func() +
+ a.getValue() + a.getValue2();
}
-// Checks that none of the function (except the always_inline_func) in the importees
-// are generated in the importer's code.
// CHECK-O0: define{{.*}}_Z3usev(
// CHECK-O0: declare{{.*}}_ZW1M13exported_funcv(
-// CHECK-O0: define{{.*}}available_externally{{.*}}_ZW1M18always_inline_funcv(
+// CHECK-O0: declare{{.*}}_ZW1M18always_inline_funcv(
+// CHECK-O0: define{{.*}}@_ZN1AIcE8getValueEv(
+// CHECK-O0: declare{{.*}}@_ZN1AIcE9getValue2Ev(
// CHECK-O0-NOT: func_in_gmf
// CHECK-O0-NOT: func_in_gmf_not_called
// CHECK-O0-NOT: non_exported_func
@@ -68,7 +87,9 @@ int use() {
// O0 to keep consistent ABI.
// CHECK-O1: define{{.*}}_Z3usev(
// CHECK-O1: declare{{.*}}_ZW1M13exported_funcv(
-// CHECK-O1: define{{.*}}available_externally{{.*}}_ZW1M18always_inline_funcv(
+// CHECK-O1: declare{{.*}}_ZW1M18always_inline_funcv(
+// CHECK-O1: define{{.*}}@_ZN1AIcE8getValueEv(
+// CHECK-O1: declare{{.*}}@_ZN1AIcE9getValue2Ev(
// CHECK-O1-NOT: func_in_gmf
// CHECK-O1-NOT: func_in_gmf_not_called
// CHECK-O1-NOT: non_exported_func
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