[clang] Improve module out of date error message

[Bigcheese]

When a pcm file has a different size or modification time than it had when it was written to another module's IMPORT table Clang emits:

<pcm> is out of date and needs to be rebuilt: module file out of date

This is difficult to understand what's happening because there are a lot of reasons that a module file can be out of date. This changes the latter part of that message to:

module file has a different size or mtime than expected

Which makes it clearer what the issue is. For future work it would be nice if a more detailed explanation of the issue could be emitted as a note instead.

[llvmbot]

@llvm/pr-subscribers-clang-modules

Author: Michael Spencer (Bigcheese)

Changes

When a pcm file has a different size or modification time than it had when it was written to another module's IMPORT table Clang emits:

<pcm> is out of date and needs to be rebuilt: module file out of date

This is difficult to understand what's happening because there are a lot of reasons that a module file can be out of date. This changes the latter part of that message to:

module file has a different size or mtime than expected

Which makes it clearer what the issue is. For future work it would be nice if a more detailed explanation of the issue could be emitted as a note instead.

---

Full diff: https://github.com/llvm/llvm-project/pull/128103.diff

1 Files Affected:

• (modified) clang/lib/Serialization/ModuleManager.cpp (+1-1)

diff --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index ba78c9ef5af67..4ecb776513d6f 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -119,7 +119,7 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
   // Note: ExpectedSize and ExpectedModTime will be 0 for MK_ImplicitModule
   // when using an ASTFileSignature.
   if (lookupModuleFile(FileName, ExpectedSize, ExpectedModTime, Entry)) {
-    ErrorStr = "module file out of date";
+    ErrorStr = "module file has a different size or mtime than expected";
     return OutOfDate;
   }
 

[llvmbot]

@llvm/pr-subscribers-clang

Author: Michael Spencer (Bigcheese)

Changes

When a pcm file has a different size or modification time than it had when it was written to another module's IMPORT table Clang emits:

<pcm> is out of date and needs to be rebuilt: module file out of date

This is difficult to understand what's happening because there are a lot of reasons that a module file can be out of date. This changes the latter part of that message to:

module file has a different size or mtime than expected

Which makes it clearer what the issue is. For future work it would be nice if a more detailed explanation of the issue could be emitted as a note instead.

---

Full diff: https://github.com/llvm/llvm-project/pull/128103.diff

1 Files Affected:

• (modified) clang/lib/Serialization/ModuleManager.cpp (+1-1)

diff --git a/clang/lib/Serialization/ModuleManager.cpp b/clang/lib/Serialization/ModuleManager.cpp
index ba78c9ef5af67..4ecb776513d6f 100644
--- a/clang/lib/Serialization/ModuleManager.cpp
+++ b/clang/lib/Serialization/ModuleManager.cpp
@@ -119,7 +119,7 @@ ModuleManager::addModule(StringRef FileName, ModuleKind Type,
   // Note: ExpectedSize and ExpectedModTime will be 0 for MK_ImplicitModule
   // when using an ASTFileSignature.
   if (lookupModuleFile(FileName, ExpectedSize, ExpectedModTime, Entry)) {
-    ErrorStr = "module file out of date";
+    ErrorStr = "module file has a different size or mtime than expected";
     return OutOfDate;
   }
 

[ChuanqiXu9]

would you like to add a test?

[Bigcheese]

Fixed the missing test change.