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[clang][deps] Use top-level modules as precompiled dependencies
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The `ASTReader` populates `Module::PresumedModuleMapFile` only for top-level modules, not submodules. To avoid generating empty `-fmodule-map-file=` arguments, make discovered modules depend on top-level precompiled modules. The granularity of submodules is not important here.

The documentation of `Module::PresumedModuleMapFile` says this field is non-empty only when building from preprocessed source. This means there can still be cases where the dependency scanner generates empty `-fmodule-map-file=` arguments. That's being addressed in separate patch: D108544.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D108647
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@jansvoboda11
jansvoboda11 committed Aug 25, 2021
1 parent 46c947a commit 3b8f536
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Showing 10 changed files with 171 additions and 3 deletions.
6 changes: 3 additions & 3 deletions clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
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Expand Up @@ -257,9 +257,9 @@ void ModuleDepCollectorPP::addModulePrebuiltDeps(
llvm::DenseSet<const Module *> &SeenSubmodules) {
for (const Module *Import : M->Imports)
if (Import->getTopLevelModule() != M->getTopLevelModule())
if (MDC.isPrebuiltModule(Import))
if (SeenSubmodules.insert(Import).second)
MD.PrebuiltModuleDeps.emplace_back(Import);
if (MDC.isPrebuiltModule(Import->getTopLevelModule()))
if (SeenSubmodules.insert(Import->getTopLevelModule()).second)
MD.PrebuiltModuleDeps.emplace_back(Import->getTopLevelModule());
}

void ModuleDepCollectorPP::addAllSubmoduleDeps(
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7 changes: 7 additions & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/cdb_pch.json
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@@ -0,0 +1,7 @@
[
{
"directory": "DIR",
"command": "clang -x c-header DIR/pch.h -fmodules -gmodules -fimplicit-module-maps -fmodules-cache-path=DIR/cache -o DIR/pch.h.gch",
"file": "DIR/pch.h"
}
]
7 changes: 7 additions & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/cdb_tu.json
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@@ -0,0 +1,7 @@
[
{
"directory": "DIR",
"command": "clang -fsyntax-only DIR/tu.c -fmodules -gmodules -fimplicit-module-maps -fmodules-cache-path=DIR/cache -include DIR/pch.h -o DIR/tu.o",
"file": "DIR/tu.c"
}
]
Empty file added clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/mod_common.h
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Empty file added clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/mod_common_sub.h
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1 change: 1 addition & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/mod_tu.h
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@@ -0,0 +1 @@
#include "mod_common_sub.h"
11 changes: 11 additions & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/module.modulemap
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@@ -0,0 +1,11 @@
module ModCommon {
header "mod_common.h"

module ModCommonSub {
header "mod_common_sub.h"
}
}

module ModTU {
header "mod_tu.h"
}
1 change: 1 addition & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/pch.h
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@@ -0,0 +1 @@
#include "mod_common.h"
1 change: 1 addition & 0 deletions clang/test/ClangScanDeps/Inputs/modules-pch-common-submodule/tu.c
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@@ -0,0 +1 @@
#include "mod_tu.h"
140 changes: 140 additions & 0 deletions clang/test/ClangScanDeps/modules-pch-common-submodule.c
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@@ -0,0 +1,140 @@
// Check that when depending on a precompiled module, we depend on the
// **top-level** module. Submodules don't have some information present (for
// example the path to the modulemap file) and depending on them might cause
// problems in the dependency scanner (e.g. generating empty `-fmodule-map-file=`
// arguments).

// RUN: rm -rf %t && mkdir %t
// RUN: cp %S/Inputs/modules-pch-common-submodule/* %t

// Scan dependencies of the PCH:
//
// RUN: sed "s|DIR|%/t|g" %S/Inputs/modules-pch-common-submodule/cdb_pch.json > %t/cdb.json
// RUN: echo -%t > %t/result_pch.json
// RUN: clang-scan-deps -compilation-database %t/cdb.json -format experimental-full \
// RUN: -generate-modules-path-args -module-files-dir %t/build >> %t/result_pch.json
// RUN: cat %t/result_pch.json | sed 's:\\\\\?:/:g' | FileCheck %s -check-prefix=CHECK-PCH
//
// CHECK-PCH: -[[PREFIX:.*]]
// CHECK-PCH-NEXT: {
// CHECK-PCH-NEXT: "modules": [
// CHECK-PCH-NEXT: {
// CHECK-PCH-NEXT: "clang-module-deps": [],
// CHECK-PCH-NEXT: "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
// CHECK-PCH-NEXT: "command-line": [
// CHECK-PCH-NEXT: "-cc1"
// CHECK-PCH: "-emit-module"
// CHECK-PCH: "-fmodules"
// CHECK-PCH: "-fmodule-name=ModCommon"
// CHECK-PCH: "-fno-implicit-modules"
// CHECK-PCH: ],
// CHECK-PCH-NEXT: "context-hash": "[[HASH_MOD_COMMON:.*]]",
// CHECK-PCH-NEXT: "file-deps": [
// CHECK-PCH-NEXT: "[[PREFIX]]/mod_common.h",
// CHECK-PCH-NEXT: "[[PREFIX]]/mod_common_sub.h",
// CHECK-PCH-NEXT: "[[PREFIX]]/module.modulemap"
// CHECK-PCH-NEXT: ],
// CHECK-PCH-NEXT: "name": "ModCommon"
// CHECK-PCH-NEXT: }
// CHECK-PCH-NEXT: ],
// CHECK-PCH-NEXT: "translation-units": [
// CHECK-PCH-NEXT: {
// CHECK-PCH-NEXT: "clang-context-hash": "[[HASH_PCH:.*]]",
// CHECK-PCH-NEXT: "clang-module-deps": [
// CHECK-PCH-NEXT: {
// CHECK-PCH-NEXT: "context-hash": "[[HASH_MOD_COMMON]]",
// CHECK-PCH-NEXT: "module-name": "ModCommon"
// CHECK-PCH-NEXT: }
// CHECK-PCH-NEXT: ],
// CHECK-PCH-NEXT: "command-line": [
// CHECK-PCH-NEXT: "-fno-implicit-modules"
// CHECK-PCH-NEXT: "-fno-implicit-module-maps"
// CHECK-PCH-NEXT: "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_COMMON]]/ModCommon-{{.*}}.pcm"
// CHECK-PCH-NEXT: "-fmodule-map-file=[[PREFIX]]/module.modulemap"
// CHECK-PCH-NEXT: ],
// CHECK-PCH-NEXT: "file-deps": [
// CHECK-PCH-NEXT: "[[PREFIX]]/pch.h"
// CHECK-PCH-NEXT: ],
// CHECK-PCH-NEXT: "input-file": "[[PREFIX]]/pch.h"
// CHECK-PCH-NEXT: }
// CHECK-PCH-NEXT: ]
// CHECK-PCH-NEXT: }

// Explicitly build the PCH:
//
// RUN: tail -n +2 %t/result_pch.json > %t/result_pch_stripped.json
// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
// RUN: --module-name=ModCommon > %t/mod_common.cc1.rsp
// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
// RUN: --tu-index=0 > %t/pch.rsp
//
// RUN: %clang @%t/mod_common.cc1.rsp
// RUN: %clang -x c-header %t/pch.h -fmodules -gmodules -fimplicit-module-maps \
// RUN: -fmodules-cache-path=%t/cache -o %t/pch.h.gch @%t/pch.rsp

// Scan dependencies of the TU:
//
// RUN: sed "s|DIR|%/t|g" %S/Inputs/modules-pch-common-submodule/cdb_tu.json > %t/cdb.json
// RUN: echo -%t > %t/result_tu.json
// RUN: clang-scan-deps -compilation-database %t/cdb.json -format experimental-full \
// RUN: -generate-modules-path-args -module-files-dir %t/build >> %t/result_tu.json
// RUN: cat %t/result_tu.json | sed 's:\\\\\?:/:g' | FileCheck %s -check-prefix=CHECK-TU
//
// CHECK-TU: -[[PREFIX:.*]]
// CHECK-TU-NEXT: {
// CHECK-TU-NEXT: "modules": [
// CHECK-TU-NEXT: {
// CHECK-TU-NEXT: "clang-module-deps": [],
// CHECK-TU-NEXT: "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
// CHECK-TU-NEXT: "command-line": [
// CHECK-TU-NEXT: "-cc1"
// CHECK-TU: "-fmodule-map-file=[[PREFIX]]/module.modulemap"
// CHECK-TU: "-emit-module"
// CHECK-TU: "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_COMMON:.*]]/ModCommon-{{.*}}.pcm"
// CHECK-TU: "-fmodules"
// CHECK-TU: "-fmodule-name=ModTU"
// CHECK-TU: "-fno-implicit-modules"
// CHECK-TU: ],
// CHECK-TU-NEXT: "context-hash": "[[HASH_MOD_TU:.*]]",
// CHECK-TU-NEXT: "file-deps": [
// CHECK-TU-NEXT: "[[PREFIX]]/mod_tu.h",
// CHECK-TU-NEXT: "[[PREFIX]]/module.modulemap"
// CHECK-TU-NEXT: ],
// CHECK-TU-NEXT: "name": "ModTU"
// CHECK-TU-NEXT: }
// CHECK-TU-NEXT: ],
// CHECK-TU-NEXT: "translation-units": [
// CHECK-TU-NEXT: {
// CHECK-TU-NEXT: "clang-context-hash": "[[HASH_TU:.*]]",
// CHECK-TU-NEXT: "clang-module-deps": [
// CHECK-TU-NEXT: {
// CHECK-TU-NEXT: "context-hash": "[[HASH_MOD_TU]]"
// CHECK-TU-NEXT: "module-name": "ModTU"
// CHECK-TU-NEXT: }
// CHECK-TU-NEXT: ],
// CHECK-TU-NEXT: "command-line": [
// CHECK-TU-NEXT: "-fno-implicit-modules",
// CHECK-TU-NEXT: "-fno-implicit-module-maps",
// CHECK-TU-NEXT: "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_TU:.*]]/ModTU-{{.*}}.pcm",
// CHECK-TU-NEXT: "-fmodule-map-file=[[PREFIX]]/module.modulemap"
// CHECK-TU-NEXT: ],
// CHECK-TU-NEXT: "file-deps": [
// CHECK-TU-NEXT: "[[PREFIX]]/tu.c",
// CHECK-TU-NEXT: "[[PREFIX]]/pch.h.gch"
// CHECK-TU-NEXT: ],
// CHECK-TU-NEXT: "input-file": "[[PREFIX]]/tu.c"
// CHECK-TU-NEXT: }
// CHECK-TU-NEXT: ]
// CHECK-TU-NEXT: }

// Explicitly build the TU:
//
// RUN: tail -n +2 %t/result_tu.json > %t/result_tu_stripped.json
// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_stripped.json \
// RUN: --module-name=ModTU > %t/mod_tu.cc1.rsp
// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_stripped.json \
// RUN: --tu-index=0 > %t/tu.rsp
//
// RUN: %clang @%t/mod_tu.cc1.rsp
// RUN: %clang -fsyntax-only %t/tu.c -fmodules -gmodules -fimplicit-module-maps \
// RUN: -fmodules-cache-path=%t/cache -include %t/pch.h -o %t/tu.o @%t/tu.rsp

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