[clang] 94ae5f9 - [clang][modules][deps] Implicit modules are out of date when their explicit imports are (#138920)

via cfe-commits cfe-commits at lists.llvm.org
Fri May 9 10:32:52 PDT 2025


Author: Jan Svoboda
Date: 2025-05-09T10:32:48-07:00
New Revision: 94ae5f9e877be7490687c35ec9883ff9746721d6

URL: https://github.com/llvm/llvm-project/commit/94ae5f9e877be7490687c35ec9883ff9746721d6
DIFF: https://github.com/llvm/llvm-project/commit/94ae5f9e877be7490687c35ec9883ff9746721d6.diff

LOG: [clang][modules][deps] Implicit modules are out of date when their explicit imports are (#138920)

The dependency scanner mixes implicitly- and explicitly-built modules.
When an implicitly-built module imports an explicitly-built one, we
never run the modification time validation checks, resulting in an
out-of-date module cache. This PR fixes that by only skipping the
modification time validation checks when both the imported module and
its importer are built explicitly.

rdar://150230022

Added: 
    clang/test/ClangScanDeps/modules-pch-common-stale.c

Modified: 
    clang/lib/Serialization/ModuleManager.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index e3d7ff4fd82a7..7f3f246bfb49e 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -110,10 +110,12 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
   // Look for the file entry. This only fails if the expected size or
   // modification time 
diff er.
   OptionalFileEntryRef Entry;
-  const bool IgnoreModTime =
-      (Type == MK_ExplicitModule || Type == MK_PrebuiltModule);
+  bool IgnoreModTime = Type == MK_ExplicitModule || Type == MK_PrebuiltModule;
+  if (ImportedBy)
+    IgnoreModTime &= ImportedBy->Kind == MK_ExplicitModule ||
+                     ImportedBy->Kind == MK_PrebuiltModule;
   if (IgnoreModTime) {
-    // If we're not expecting to pull this file out of the module cache, it
+    // If neither this file nor the importer are in the module cache, this file
     // might have a 
diff erent mtime due to being moved across filesystems in
     // a distributed build. The size must still match, though. (As must the
     // contents, but we can't check that.)

diff  --git a/clang/test/ClangScanDeps/modules-pch-common-stale.c b/clang/test/ClangScanDeps/modules-pch-common-stale.c
new file mode 100644
index 0000000000000..100124d9ad0b0
--- /dev/null
+++ b/clang/test/ClangScanDeps/modules-pch-common-stale.c
@@ -0,0 +1,178 @@
+// Test that modifications to a common header (imported from both a PCH and a TU)
+// cause rebuilds of dependent modules imported from the TU on incremental build.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+//--- module.modulemap
+module mod_common { header "mod_common.h" }
+module mod_tu { header "mod_tu.h" }
+module mod_tu_extra { header "mod_tu_extra.h" }
+
+//--- mod_common.h
+#define MOD_COMMON_MACRO 0
+//--- mod_tu.h
+#include "mod_common.h"
+#if MOD_COMMON_MACRO
+#include "mod_tu_extra.h"
+#endif
+
+//--- mod_tu_extra.h
+
+//--- prefix.h
+#include "mod_common.h"
+
+//--- tu.c
+#include "mod_tu.h"
+
+// Clean: scan the PCH.
+// RUN: clang-scan-deps -format experimental-full -o %t/deps_pch_clean.json -- \
+// RUN:     %clang -x c-header %t/prefix.h -o %t/prefix.h.pch -F %t \
+// RUN:     -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache
+
+// Clean: build the PCH.
+// RUN: %deps-to-rsp %t/deps_pch_clean.json --module-name mod_common > %t/mod_common.rsp
+// RUN: %deps-to-rsp %t/deps_pch_clean.json --tu-index 0 > %t/pch.rsp
+// RUN: %clang @%t/mod_common.rsp
+// RUN: %clang @%t/pch.rsp
+
+// Clean: scan the TU.
+// RUN: clang-scan-deps -format experimental-full -o %t/deps_tu_clean.json -- \
+// RUN:     %clang -c %t/tu.c -o %t/tu.o -include %t/prefix.h -F %t \
+// RUN:     -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache
+// RUN: cat %t/deps_tu_clean.json | sed 's:\\\\\?:/:g' | FileCheck %s --check-prefix=CHECK-TU-CLEAN -DPREFIX=%/t
+// CHECK-TU-CLEAN:      {
+// CHECK-TU-CLEAN-NEXT:   "modules": [
+// CHECK-TU-CLEAN-NEXT:     {
+// CHECK-TU-CLEAN-NEXT:       "clang-module-deps": [],
+// CHECK-TU-CLEAN-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-TU-CLEAN-NEXT:       "command-line": [
+// CHECK-TU-CLEAN:            ],
+// CHECK-TU-CLEAN-NEXT:       "context-hash": "{{.*}}",
+// CHECK-TU-CLEAN-NEXT:       "file-deps": [
+// CHECK-TU-CLEAN-NEXT:         "[[PREFIX]]/module.modulemap",
+// CHECK-TU-CLEAN-NEXT:         "[[PREFIX]]/mod_tu.h"
+// CHECK-TU-CLEAN-NEXT:       ],
+// CHECK-TU-CLEAN-NEXT:       "link-libraries": [],
+// CHECK-TU-CLEAN-NEXT:       "name": "mod_tu"
+// CHECK-TU-CLEAN-NEXT:     }
+// CHECK-TU-CLEAN-NEXT:   ],
+// CHECK-TU-CLEAN-NEXT:   "translation-units": [
+// CHECK-TU-CLEAN-NEXT:     {
+// CHECK-TU-CLEAN-NEXT:       "commands": [
+// CHECK-TU-CLEAN-NEXT:         {
+// CHECK-TU-CLEAN-NEXT:           "clang-context-hash": "{{.*}}",
+// CHECK-TU-CLEAN-NEXT:           "clang-module-deps": [
+// CHECK-TU-CLEAN-NEXT:             {
+// CHECK-TU-CLEAN-NEXT:               "context-hash": "{{.*}}",
+// CHECK-TU-CLEAN-NEXT:               "module-name": "mod_tu"
+// CHECK-TU-CLEAN-NEXT:             }
+// CHECK-TU-CLEAN-NEXT:           ],
+// CHECK-TU-CLEAN-NEXT:           "command-line": [
+// CHECK-TU-CLEAN:                ],
+// CHECK-TU-CLEAN-NEXT:           "executable": "{{.*}}",
+// CHECK-TU-CLEAN-NEXT:           "file-deps": [
+// CHECK-TU-CLEAN-NEXT:             "[[PREFIX]]/tu.c",
+// CHECK-TU-CLEAN-NEXT:             "[[PREFIX]]/prefix.h.pch"
+// CHECK-TU-CLEAN-NEXT:           ],
+// CHECK-TU-CLEAN-NEXT:           "input-file": "[[PREFIX]]/tu.c"
+// CHECK-TU-CLEAN-NEXT:         }
+// CHECK-TU-CLEAN-NEXT:       ]
+// CHECK-TU-CLEAN-NEXT:     }
+// CHECK-TU-CLEAN:        ]
+// CHECK-TU-CLEAN:      }
+
+// Clean: build the TU.
+// RUN: %deps-to-rsp %t/deps_tu_clean.json --module-name mod_tu > %t/mod_tu.rsp
+// RUN: %deps-to-rsp %t/deps_tu_clean.json --tu-index 0 > %t/tu.rsp
+// RUN: %clang @%t/mod_tu.rsp
+// RUN: %clang @%t/tu.rsp
+
+// Incremental: modify the common module.
+// RUN: sleep 1
+// RUN: echo "#define MOD_COMMON_MACRO 1" > %t/mod_common.h
+
+// Incremental: scan the PCH.
+// RUN: clang-scan-deps -format experimental-full -o %t/deps_pch_incremental.json -- \
+// RUN:     %clang -x c-header %t/prefix.h -o %t/prefix.h.pch -F %t \
+// RUN:     -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache
+
+// Incremental: build the PCH.
+// RUN: %deps-to-rsp %t/deps_pch_incremental.json --module-name mod_common > %t/mod_common.rsp
+// RUN: %deps-to-rsp %t/deps_pch_incremental.json --tu-index 0 > %t/pch.rsp
+// RUN: %clang @%t/mod_common.rsp
+// RUN: %clang @%t/pch.rsp
+
+// Incremental: scan the TU. This needs to invalidate modules imported from the
+//              TU that depend on modules imported from the PCH and discover the
+//              new dependency on 'mod_tu_extra'.
+// RUN: clang-scan-deps -format experimental-full -o %t/deps_tu_incremental.json -- \
+// RUN:     %clang -c %t/tu.c -o %t/tu.o -include %t/prefix.h -F %t \
+// RUN:     -fmodules -fimplicit-module-maps -fmodules-cache-path=%t/cache
+// RUN: cat %t/deps_tu_incremental.json | sed 's:\\\\\?:/:g' | FileCheck %s --check-prefix=CHECK-TU-INCREMENTAL -DPREFIX=%/t
+// CHECK-TU-INCREMENTAL:      {
+// CHECK-TU-INCREMENTAL-NEXT:   "modules": [
+// CHECK-TU-INCREMENTAL-NEXT:     {
+// CHECK-TU-INCREMENTAL-NEXT:       "clang-module-deps": [
+// CHECK-TU-INCREMENTAL-NEXT:         {
+// CHECK-TU-INCREMENTAL-NEXT:           "context-hash": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:           "module-name": "mod_tu_extra"
+// CHECK-TU-INCREMENTAL-NEXT:         }
+// CHECK-TU-INCREMENTAL-NEXT:       ],
+// CHECK-TU-INCREMENTAL-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-TU-INCREMENTAL-NEXT:       "command-line": [
+// CHECK-TU-INCREMENTAL:            ],
+// CHECK-TU-INCREMENTAL-NEXT:       "context-hash": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:       "file-deps": [
+// CHECK-TU-INCREMENTAL-NEXT:         "[[PREFIX]]/module.modulemap",
+// CHECK-TU-INCREMENTAL-NEXT:         "[[PREFIX]]/mod_tu.h"
+// CHECK-TU-INCREMENTAL-NEXT:       ],
+// CHECK-TU-INCREMENTAL-NEXT:       "link-libraries": [],
+// CHECK-TU-INCREMENTAL-NEXT:       "name": "mod_tu"
+// CHECK-TU-INCREMENTAL-NEXT:     },
+// CHECK-TU-INCREMENTAL-NEXT:     {
+// CHECK-TU-INCREMENTAL-NEXT:       "clang-module-deps": [],
+// CHECK-TU-INCREMENTAL-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-TU-INCREMENTAL-NEXT:       "command-line": [
+// CHECK-TU-INCREMENTAL:            ],
+// CHECK-TU-INCREMENTAL-NEXT:       "context-hash": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:       "file-deps": [
+// CHECK-TU-INCREMENTAL-NEXT:         "[[PREFIX]]/module.modulemap",
+// CHECK-TU-INCREMENTAL-NEXT:         "[[PREFIX]]/mod_tu_extra.h"
+// CHECK-TU-INCREMENTAL-NEXT:       ],
+// CHECK-TU-INCREMENTAL-NEXT:       "link-libraries": [],
+// CHECK-TU-INCREMENTAL-NEXT:       "name": "mod_tu_extra"
+// CHECK-TU-INCREMENTAL-NEXT:     }
+// CHECK-TU-INCREMENTAL-NEXT:   ],
+// CHECK-TU-INCREMENTAL-NEXT:   "translation-units": [
+// CHECK-TU-INCREMENTAL-NEXT:     {
+// CHECK-TU-INCREMENTAL-NEXT:       "commands": [
+// CHECK-TU-INCREMENTAL-NEXT:         {
+// CHECK-TU-INCREMENTAL-NEXT:           "clang-context-hash": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:           "clang-module-deps": [
+// CHECK-TU-INCREMENTAL-NEXT:             {
+// CHECK-TU-INCREMENTAL-NEXT:               "context-hash": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:               "module-name": "mod_tu"
+// CHECK-TU-INCREMENTAL-NEXT:             }
+// CHECK-TU-INCREMENTAL-NEXT:           ],
+// CHECK-TU-INCREMENTAL-NEXT:           "command-line": [
+// CHECK-TU-INCREMENTAL:                ],
+// CHECK-TU-INCREMENTAL-NEXT:           "executable": "{{.*}}",
+// CHECK-TU-INCREMENTAL-NEXT:           "file-deps": [
+// CHECK-TU-INCREMENTAL-NEXT:             "[[PREFIX]]/tu.c",
+// CHECK-TU-INCREMENTAL-NEXT:             "[[PREFIX]]/prefix.h.pch"
+// CHECK-TU-INCREMENTAL-NEXT:           ],
+// CHECK-TU-INCREMENTAL-NEXT:           "input-file": "[[PREFIX]]/tu.c"
+// CHECK-TU-INCREMENTAL-NEXT:         }
+// CHECK-TU-INCREMENTAL-NEXT:       ]
+// CHECK-TU-INCREMENTAL-NEXT:     }
+// CHECK-TU-INCREMENTAL:        ]
+// CHECK-TU-INCREMENTAL:      }
+
+// Incremental: build the TU.
+// RUN: %deps-to-rsp %t/deps_tu_incremental.json --module-name mod_tu_extra > %t/mod_tu_extra.rsp
+// RUN: %deps-to-rsp %t/deps_tu_incremental.json --module-name mod_tu > %t/mod_tu.rsp
+// RUN: %deps-to-rsp %t/deps_tu_incremental.json --tu-index 0 > %t/tu.rsp
+// RUN: %clang @%t/mod_tu_extra.rsp
+// RUN: %clang @%t/mod_tu.rsp
+// RUN: %clang @%t/tu.rsp


        


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