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[clang][modules] Allow module maps with textual headers to be non-affecting #89441

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Merged
merged 8 commits into from
Apr 24, 2024
Merged

[clang][modules] Allow module maps with textual headers to be non-affecting #89441

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9165d60
[clang][modules] Allow module map files with textual header be non-af…
jansvoboda11 Apr 19, 2024
17b1860
[clang][modules] Mark 'use'd modules as affecting
jansvoboda11 Apr 22, 2024
9eeea3f
[clang][modules] Do consider module maps of included textual headers …
jansvoboda11 Apr 23, 2024
ddc6bf9
Reject all non-included headers from that are !isCompilingModuleHeade…
jansvoboda11 Apr 23, 2024
2993a63
Don't add modules for textual headers to `ModulesToProcess`
jansvoboda11 Apr 23, 2024
b03c34f
**Locally** included
jansvoboda11 Apr 23, 2024
1228f5c
Fix test on Windows
jansvoboda11 Apr 24, 2024
14ac904
Split out HFI conditions
jansvoboda11 Apr 24, 2024
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10 changes: 6 additions & 4 deletions clang/lib/Serialization/ASTWriter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -187,7 +187,8 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
continue;

const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader))
if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
!HFI->isCompilingModuleHeader))
continue;

for (const auto &KH : HS.findResolvedModulesForHeader(*File)) {
Expand Down Expand Up @@ -2055,11 +2056,12 @@ void ASTWriter::WriteHeaderSearch(const HeaderSearch &HS) {

// Get the file info. Skip emitting this file if we have no information on
// it as a header file (in which case HFI will be null) or if it hasn't
// changed since it was loaded. Also skip it if it's for a modular header
// from a different module; in that case, we rely on the module(s)
// changed since it was loaded. Also skip it if it's for a non-excluded
// header from a different module; in that case, we rely on the module(s)
// containing the header to provide this information.
const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader))
if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
!HFI->isCompilingModuleHeader))
continue;

// Massage the file path into an appropriate form.
Expand Down
26 changes: 26 additions & 0 deletions clang/test/Modules/prune-non-affecting-module-map-files-textual.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
// This test checks that a module map with a textual header can be marked as
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This is a useful test, I think there are a couple of other affecting-ness properties that are important to test:

  • that a textual header that is included means its module is affecting (i.e. the include matters)
  • that this textual-affecting-ness doesn't leak outside the module (a module depending on B isn't affected by A.modulemap)

I tried to cover these in https://github.com/llvm/llvm-project/pull/89729/files#diff-2eed05f9a85bc5a79b9651ee0f23e5f1494e94a2f32e093847aa6dae5ce5d839 - it might be nice to add these as a second test here (I can do it as a followup if you prefer)

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This patch unfortunately doesn't pass that test (on line 44) due to this: when computing affecting module maps for B, "A.h" makes it through the HFI filter, module A is added to ModulesToProcess and the module map for its import X is considered affecting.

I tried splitting up that logic so that we consider imports and undeclared uses only of the current module and its submodules. That doesn't work either, because PP.alreadyIncluded("X.h") returns true, since it checks the global (cross-module) state, not the local state. This might be possible with #71117. Until then, I think we need some "has this been included locally" state that's local to the current TU. Maybe that can live in HeaderFileInfo as per your patch, or as a Preprocessor state.

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Should work with b03c34f.

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(And thanks for the extended test case!)

// non-affecting.

// RUN: rm -rf %t && mkdir %t
// RUN: split-file %s %t

//--- A.modulemap
module A { textual header "A.h" }
//--- B.modulemap
module B { header "B.h" export * }
//--- A.h
typedef int A_int;
//--- B.h
#include "A.h"
typedef A_int B_int;

// RUN: %clang_cc1 -fmodules -emit-module %t/A.modulemap -fmodule-name=A -o %t/A.pcm \
// RUN: -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap

// RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B0.pcm \
// RUN: -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm

// RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B1.pcm \
// RUN: -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm

// RUN: diff %t/B0.pcm %t/B1.pcm