RUN: rm -rf %t 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 -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 included in the program if the module is used, even if the header containing the inline asm is never included - unlike a non-modular build). This is inconsistent with how namespace scope static variables are handled - where they only appear in the code that includes a header. This functionality was implemented to workaround/support the initialization of iostreams (implemented as a namespace scope static in the header - only to be provided when that specific header is included in the program). FOO: module asm "narf" 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]*}}) Test that implicit special members are emitted into the FOO module if they're ODR used there, otherwise emit them linkonce_odr as usual in the use. FIXME: Proactively instantiate any valid implicit special members to emit them into the module object. FOO: define weak_odr void @_ZN13implicit_dtorD1Ev FOO: define weak_odr void @_Z4instIfEvv 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 module's object. Users of the module only get a declaration. 'distinct' is used for definition records (the flags field is empty/unspecified) FOO: = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "implicit_dtor" Declarations are non-distinct and include the 'DIFlagFwdDecl' flag. USE: = !DICompositeType(tag: DW_TAG_structure_type, name: "implicit_dtor", {{.*}}, flags: DIFlagFwdDecl