From: David Blaikie <dblaikie@gmail.com>
Date: Thu, 2 Nov 2017 22:28:50 +0000 (+0000)
Subject: Modular Codegen: Don't home always_inline functions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4e3af04476f8d7714ccdcfe6c6bf56050fdfba45;p=clang

Modular Codegen: Don't home always_inline functions

Since they'll likely (not always - if the address is taken, etc) be
inlined away, even at -O0, separately provided weak definitions are
likely to be unused so skip all of that.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@317279 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index bf34d01751..e940806094 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -2270,9 +2270,11 @@ void ASTRecordWriter::AddFunctionDefinition(const FunctionDecl *FD) {
     if (Writer->Context->getLangOpts().ModulesCodegen) {
       // Under -fmodules-codegen, codegen is performed for all non-internal,
       // non-always_inline functions.
-      if (!Linkage)
-        Linkage = Writer->Context->GetGVALinkageForFunction(FD);
-      ModulesCodegen = *Linkage != GVA_Internal;
+      if (!FD->hasAttr<AlwaysInlineAttr>()) {
+        if (!Linkage)
+          Linkage = Writer->Context->GetGVALinkageForFunction(FD);
+        ModulesCodegen = *Linkage != GVA_Internal;
+      }
     }
   }
   Record->push_back(ModulesCodegen);
diff --git a/test/Modules/Inputs/codegen/foo.h b/test/Modules/Inputs/codegen/foo.h
index bd3b6489e7..76ad6559cc 100644
--- a/test/Modules/Inputs/codegen/foo.h
+++ b/test/Modules/Inputs/codegen/foo.h
@@ -29,4 +29,7 @@ inline void inst_decl() {
   inst<float>();
 }
 
+__attribute__((always_inline)) inline void always_inl() {
+}
+
 asm("narf");
diff --git a/test/Modules/Inputs/codegen/use.cpp b/test/Modules/Inputs/codegen/use.cpp
index cd1a4a642d..3e551881f6 100644
--- a/test/Modules/Inputs/codegen/use.cpp
+++ b/test/Modules/Inputs/codegen/use.cpp
@@ -6,3 +6,6 @@ void non_modular_use_of_implicit_dtor() {
 void use_of_instantiated_declaration_without_definition() {
   inst<int>();
 }
+void call_always_inline() {
+  always_inl();
+}
diff --git a/test/Modules/codegen.test b/test/Modules/codegen.test
index 1bdea5df43..a919933da2 100644
--- a/test/Modules/codegen.test
+++ b/test/Modules/codegen.test
@@ -4,7 +4,7 @@ REQUIRES: x86-registered-target
 RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -fmodules-debuginfo -x c++ -fmodules -emit-module -fmodule-name=foo %S/Inputs/codegen/foo.modulemap -o %t/foo.pcm
 
 RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -debug-info-kind=limited -o - %t/foo.pcm | FileCheck --check-prefix=FOO --check-prefix=BOTH %s
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -debug-info-kind=limited -o - -fmodules -fmodule-file=%t/foo.pcm %S/Inputs/codegen/use.cpp | FileCheck --check-prefix=BOTH --check-prefix=USE %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -debug-info-kind=limited -o - -fmodules -disable-llvm-passes -fmodule-file=%t/foo.pcm %S/Inputs/codegen/use.cpp | FileCheck --check-prefix=BOTH --check-prefix=USE %s
 
 For want of any better definition, inline asm goes "everywhere" the same as it
 if it were in a header (with the disadvantage that the inline asm will be
@@ -23,6 +23,7 @@ USE: module asm "narf"
 FOO: $_Z2f1PKcz = comdat any
 FOO: $_ZN13implicit_dtorD1Ev = comdat any
 USE: $_Z4instIiEvv = comdat any
+USE: $_Z10always_inlv = comdat any
 FOO: $_ZN13implicit_dtorD2Ev = comdat any
 FOO: define weak_odr void @_Z2f1PKcz(i8* %fmt, ...) #{{[0-9]+}} comdat
 FOO:   call void @llvm.va_start(i8* %{{[a-zA-Z0-9]*}})
@@ -38,6 +39,7 @@ FOO: define weak_odr void @_ZN13implicit_dtorD2Ev
 
 USE: define linkonce_odr void @_ZN20uninst_implicit_dtorD1Ev
 USE: define linkonce_odr void @_Z4instIiEvv
+USE: define linkonce_odr void @_Z10always_inlv
 USE: define linkonce_odr void @_ZN20uninst_implicit_dtorD2Ev
 
 Modular debug info puts the definition of a class defined in a module in that