RUN: rm -rf %t REQUIRES: x86-registered-target RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=foo %S/Inputs/codegen-opt/foo.modulemap -o %t/foo.pcm RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=bar %S/Inputs/codegen-opt/bar.modulemap -o %t/bar.pcm -fmodule-file=%t/foo.pcm RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/foo.pcm | FileCheck --check-prefix=FOO %s RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR %s RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen-opt/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE %s RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/foo.pcm | FileCheck --check-prefix=FOO %s RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR-OPT %s RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen-opt/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE-OPT %s FOO-NOT: comdat FOO: $_Z3foov = comdat any FOO: $_Z4foo2v = comdat any FOO: $_ZZ3foovE1i = comdat any FOO: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat FOO-NOT: {{comdat|define|declare}} FOO: define{{.*}} void @_Z7foo_extv() FOO-NOT: {{define|declare}} FOO: define weak_odr void @_Z3foov() #{{[0-9]+}} comdat FOO-NOT: {{define|declare}} FOO: declare void @_Z2f1Ri(i32* FOO-NOT: {{define|declare}} Internal functions are not modularly code generated - they are internal wherever they're used. This might not be ideal, but continues to workaround/support some oddities that backwards compatible modules have seen and supported in the wild. To remove the duplication here, the internal functions would need to be promoted to weak_odr, placed in comdat and given a new mangling - this would be needed for the C++ Modules TS anyway. FOO: define internal void @_ZL2f2v() #{{[0-9]+}} FOO-NOT: {{define|declare}} FOO: define weak_odr void @_Z4foo2v() #{{[0-9]+}} comdat FOO-NOT: {{define|declare}} BAR-CMN-NOT: comdat BAR-CMN: $_Z3barv = comdat any BAR-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat BAR-CMN-NOT: {{comdat|define|declare}} BAR-CMN: define weak_odr void @_Z3barv() #{{[0-9]+}} comdat BAR-CMN-NOT: {{define|declare}} BAR: declare void @_Z3foov() Include all the available_externally definitions required for bar (foo -> f2) BAR-OPT: define available_externally void @_Z3foov() BAR-CMN-NOT: {{define|declare}} BAR-OPT: declare void @_Z2f1Ri(i32* BAR-OPT-NOT: {{define|declare}} BAR-OPT: define internal void @_ZL2f2v() BAR-OPT-NOT: {{define|declare}} USE-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat USE-CMN-NOT: {{comdat|define|declare}} USE-CMN: define{{.*}} i32 @main() USE-CMN-NOT: {{define|declare}} USE: declare void @_Z3barv() Include all the available_externally definitions required for main (bar -> foo -> f2) USE-OPT: define available_externally void @_Z3barv() USE-CMN-NOT: {{define|declare}} USE-OPT: define available_externally void @_Z3foov() USE-OPT-NOT: {{define|declare}} USE-OPT: declare void @_Z2f1Ri(i32* USE-OPT-NOT: {{define|declare}} USE-OPT: define internal void @_ZL2f2v() USE-OPT-NOT: {{define|declare}}