[PATCH] D113545: [C++20] [Module] Support reachable definition initially/partially

Iain Sandoe via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Jun 21 03:19:19 PDT 2022

iains added a comment.

@ChuanqiXu - have you tried the test example from 10.6 ex1  - I did the impl as below, but the behaviour does not seem to be quite correct?
any thoughts?

As for review, I can try to pick up the "nits" but not sure that I know the instantiation sub=system too well, so it would be better if @rsmith could cast an eye over those parts.

let's discuss the 10.6 example first (I'd guess 10.7 cases will need to be reviewed too)

  // RUN: rm -rf %t
  // RUN: split-file %s %t
  // RUN: cd %t
  // RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-header-unit-header std-10-6-ex1-decl.h \
  // RUN: -o decl.pcm
  // RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-header-unit-header std-10-6-ex1-defn.h \
  // RUN: -o defn.pcm
  // RUN: %clang_cc1 -std=c++20 -emit-module-interface std-10-6-ex1-stuff.cpp \
  // RUN: -o stuff.pcm
  // RUN: %clang_cc1 -std=c++20 -emit-module-interface std-10-6-ex1-M1.cpp \
  // RUN: -fmodule-file=stuff.pcm -o M1.pcm  -fmodule-file=defn.pcm
  // RUN: %clang_cc1 -std=c++20 -emit-module-interface std-10-6-ex1-M2.cpp \
  // RUN: -fmodule-file=stuff.pcm -o M2.pcm  -fmodule-file=decl.pcm
  // RUN: %clang_cc1 -std=c++20 std-10-6-ex1-use.cpp \
  // RUN: -fmodule-file=M1.pcm -fmodule-file=M2.pcm  -fsyntax-only
  //--- std-10-6-ex1-decl.h
  struct X;
  //--- std-10-6-ex1-defn.h
  struct X {};
  //--- std-10-6-ex1-stuff.cpp
  export module stuff;
  export template<typename T, typename U> void foo(T, U u) { auto v = u; }
  export template<typename T, typename U> void bar(T, U u) { auto v = *u; }
  //--- std-10-6-ex1-M1.cpp
  export module M1;
  import "std-10-6-ex1-defn.h"; // provides struct X {};
  import stuff;
  export template<typename T> void f(T t) {
    X x;
    foo(t, x); 
  //--- std-10-6-ex1-M2.cpp
  export module M2;
  import "std-10-6-ex1-decl.h"; // provides struct X; (not a definition)
  import stuff;
  export template<typename T> void g(T t) {
    X *x;
    bar(t, x); 
  //--- std-10-6-ex1-use.cpp
  import M1;
  import M2;
  void test() {

(I think we might also have some issues with poor diagnostics for items in PMF (saying that an import is required before use, but of course that import is impossible - e.g. 10.5)



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