[clang][modules] Don't prevent translation of FW_Private includes when explicitly building FW

[jansvoboda11]

We prevent translating #include <FW/PrivateHeader.h> into an import of FW_Private when compiling the implementation of FW or FW_Private. This is specified via -fmodule-name= on the TU command line (used to be -fmodule-implementation-of).

This logic is supposed to only kick in when imported directly from a TU, but it currently also kicks in when compiling the public FW module explicitly (since it also has -fmodule-name= on the command line).

This patch makes sure this logic only kicks in for the case that used to be -fmodule-implementation-of (for the TU), and not for all -fmodule-name= cases (especially for the explicit compile of a module).

rdar://101051277; related: rdar://37500098&38434694

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-modules

Author: Jan Svoboda (jansvoboda11)

Changes

We prevent translating #include <FW/PrivateHeader.h> into an import of FW_Private when compiling the implementation of FW or FW_Private. This is specified via -fmodule-name= on the TU command line (used to be -fmodule-implementation-of).

This logic is supposed to only kick in when imported directly from a TU, but it currently also kicks in when compiling the public FW module explicitly (since it also has -fmodule-name= on the command line).

This patch makes sure this logic only kicks in for the case that used to be -fmodule-implementation-of (for the TU), and not for all -fmodule-name= cases (especially for the explicit compile of a module).

rdar://101051277; related: rdar://37500098&38434694

---

Full diff: https://github.com/llvm/llvm-project/pull/70714.diff

2 Files Affected:

• (modified) clang/lib/Basic/Module.cpp (+4-3)
• (added) clang/test/ClangScanDeps/modules-priv-fw-from-pub.m (+121)

diff --git a/clang/lib/Basic/Module.cpp b/clang/lib/Basic/Module.cpp
index cc2e5be98d32d34..e4ac1abf12a7f8e 100644
--- a/clang/lib/Basic/Module.cpp
+++ b/clang/lib/Basic/Module.cpp
@@ -161,9 +161,10 @@ bool Module::isForBuilding(const LangOptions &LangOpts) const {
   StringRef TopLevelName = getTopLevelModuleName();
   StringRef CurrentModule = LangOpts.CurrentModule;
 
-  // When building framework Foo, we want to make sure that Foo *and*
-  // Foo_Private are textually included and no modules are built for both.
-  if (getTopLevelModule()->IsFramework &&
+  // When building the implementation of framework Foo, we want to make sure
+  // that Foo *and* Foo_Private are textually included and no modules are built
+  // for either.
+  if (!LangOpts.isCompilingModule() && getTopLevelModule()->IsFramework &&
       CurrentModule == LangOpts.ModuleName &&
       !CurrentModule.endswith("_Private") && TopLevelName.endswith("_Private"))
     TopLevelName = TopLevelName.drop_back(8);
diff --git a/clang/test/ClangScanDeps/modules-priv-fw-from-pub.m b/clang/test/ClangScanDeps/modules-priv-fw-from-pub.m
new file mode 100644
index 000000000000000..cb82e0c366322c9
--- /dev/null
+++ b/clang/test/ClangScanDeps/modules-priv-fw-from-pub.m
@@ -0,0 +1,121 @@
+// This test checks that importing private headers from the public headers of
+// a framework is consistent between the dependency scanner and the explicit build.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+//--- frameworks/FW.framework/Modules/module.modulemap
+framework module FW { header "FW.h" }
+//--- frameworks/FW.framework/Modules/module.private.modulemap
+framework module FW_Private { header "FW_Private.h"}
+//--- frameworks/FW.framework/Headers/FW.h
+#include <FW/FW_Private.h>
+//--- frameworks/FW.framework/PrivateHeaders/FW_Private.h
+@import Dependency;
+
+//--- modules/module.modulemap
+module Dependency { header "dependency.h" }
+//--- modules/dependency.h
+// empty
+
+//--- tu.m
+#include <FW/FW.h>
+
+//--- cdb.json.in
+[{
+  "file": "DIR/tu.m",
+  "directory": "DIR",
+  "command": "clang -fmodules -fmodules-cache-path=DIR/cache -fimplicit-module-maps -I DIR/modules -F DIR/frameworks -Wno-framework-include-private-from-public -Wno-atimport-in-framework-header -c DIR/tu.m -o DIR/tu.o"
+}]
+
+// RUN: sed -e "s|DIR|%/t|g" %t/cdb.json.in > %t/cdb.json
+// RUN: clang-scan-deps -compilation-database %t/cdb.json -format experimental-full > %t/deps.json
+
+// Check that FW is reported to depend on FW_Private.
+// RUN: cat %t/deps.json | sed 's:\\\\\?:/:g' | FileCheck %s -DPREFIX=%/t
+// CHECK:      {
+// CHECK-NEXT:   "modules": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "clang-module-deps": [],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/modules/module.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/modules/dependency.h",
+// CHECK-NEXT:         "[[PREFIX]]/modules/module.modulemap"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "Dependency"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "clang-module-deps": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "context-hash": "{{.*}}",
+// CHECK-NEXT:           "module-name": "FW_Private"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/frameworks/FW.framework/Modules/module.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/frameworks/FW.framework/Headers/FW.h",
+// CHECK-NEXT:         "[[PREFIX]]/frameworks/FW.framework/Modules/module.modulemap",
+// CHECK-NEXT:         "[[PREFIX]]/frameworks/FW.framework/Modules/module.private.modulemap"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "FW"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "clang-module-deps": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "context-hash": "{{.*}}",
+// CHECK-NEXT:           "module-name": "Dependency"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/frameworks/FW.framework/Modules/module.private.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/frameworks/FW.framework/Modules/module.private.modulemap",
+// CHECK-NEXT:         "[[PREFIX]]/frameworks/FW.framework/PrivateHeaders/FW_Private.h",
+// CHECK-NEXT:         "[[PREFIX]]/modules/module.modulemap"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "FW_Private"
+// CHECK-NEXT:     }
+// CHECK-NEXT:   ],
+// CHECK-NEXT:   "translation-units": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "commands": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "clang-context-hash": "{{.*}}",
+// CHECK-NEXT:           "clang-module-deps": [
+// CHECK-NEXT:             {
+// CHECK-NEXT:               "context-hash": "{{.*}}",
+// CHECK-NEXT:               "module-name": "FW"
+// CHECK-NEXT:             }
+// CHECK-NEXT:           ],
+// CHECK-NEXT:           "command-line": [
+// CHECK:                ],
+// CHECK-NEXT:           "executable": "clang",
+// CHECK-NEXT:           "file-deps": [
+// CHECK-NEXT:             "[[PREFIX]]/tu.m"
+// CHECK-NEXT:           ],
+// CHECK-NEXT:           "input-file": "[[PREFIX]]/tu.m"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ]
+// CHECK-NEXT:     }
+// CHECK-NEXT:   ]
+// CHECK-NEXT: }
+
+// Check that building FW succeeds. If FW_Private was to be treated textually,
+// building FW would fail due to Dependency not being present on the command line.
+// RUN: %deps-to-rsp %t/deps.json --module-name=Dependency > %t/Dependency.cc1.rsp
+// RUN: %deps-to-rsp %t/deps.json --module-name=FW_Private > %t/FW_Private.cc1.rsp
+// RUN: %deps-to-rsp %t/deps.json --module-name=FW > %t/FW.cc1.rsp
+// RUN: %deps-to-rsp %t/deps.json --tu-index=0 > %t/tu.rsp
+
+// RUN: %clang @%t/Dependency.cc1.rsp
+// RUN: %clang @%t/FW_Private.cc1.rsp
+// RUN: %clang @%t/FW.cc1.rsp
+// RUN: %clang @%t/tu.rsp