https://github.com/naveen-seth updated
https://github.com/llvm/llvm-project/pull/133462
>From 957a45312767a40b513bfd4f545c23fda9c4866f Mon Sep 17 00:00:00 2001
From: naveen-seth <naveen.ha...@outlook.com>
Date: Tue, 8 Apr 2025 00:56:14 +0000
Subject: [PATCH] [clang][modules] Guard against bad -fmodule-file mappings
(#132059)
[clang][modules] Guard against invalid -fmodule-file mappings
Fixes #132059.
Providing incorrect mappings via `-fmodule-file=<name>=<path/to/bmi>`
can cause the compiler to crash when loading a module that imports an
incorrectly mapped module.
The crash occurs during AST body deserialization when the compiler
attempts to resolve remappings using the `ModuleFile` from the
incorrectly mapped module's BMI file.
The cause is an invalid access into an incorrectly loaded
`ModuleFile`.
This commit fixes the issue by verifying the identity of the imported
module.
---
clang/lib/Serialization/ASTReader.cpp | 12 +++++
clang/test/Modules/fmodule-file-mismatch.cppm | 48 +++++++++++++++++++
2 files changed, 60 insertions(+)
create mode 100644 clang/test/Modules/fmodule-file-mismatch.cppm
diff --git a/clang/lib/Serialization/ASTReader.cpp
b/clang/lib/Serialization/ASTReader.cpp
index 0cd2cedb48dd9..2f1627d234a4e 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -3318,6 +3318,18 @@ ASTReader::ReadControlBlock(ModuleFile &F,
Loaded, StoredSize, StoredModTime,
StoredSignature, Capabilities);
+ // Check the AST we just read from ImportedFile contains a different
+ // module than we expected (ImportedName). This can occur for C++20
+ // Modules when given a mismatch via -fmodule-file=<name>=<file>
+ if (IsImportingStdCXXModule) {
+ if (const auto *Imported =
+ getModuleManager().lookupByFileName(ImportedFile);
+ Imported != nullptr && Imported->ModuleName != ImportedName) {
+ Diag(diag::err_failed_to_find_module_file) << ImportedName;
+ Result = Missing;
+ }
+ }
+
// If we diagnosed a problem, produce a backtrace.
bool recompilingFinalized = Result == OutOfDate &&
(Capabilities & ARR_OutOfDate) &&
diff --git a/clang/test/Modules/fmodule-file-mismatch.cppm
b/clang/test/Modules/fmodule-file-mismatch.cppm
new file mode 100644
index 0000000000000..351f3f4295bf0
--- /dev/null
+++ b/clang/test/Modules/fmodule-file-mismatch.cppm
@@ -0,0 +1,48 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+
+// Related to issue #132059
+
+// Precompile the module dependencies correctly
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface a.cppm -o a.pcm
+// RUN: %clang_cc1 -std=c++20 -emit-module-interface b.cppm -o b.pcm \
+// RUN: -fmodule-file=A=a.pcm
+
+// Verify that providing incorrect mappings via
+// `-fmodule-file=<name>=<path/to/bmi>` does not crash the compiler when
loading
+// a module that imports the incorrectly mapped module.
+// RUN: not %clang_cc1 -std=c++20 main1.cpp -fmodule-file=A=b.pcm
+
+//--- a.cppm
+export module A;
+
+export int a() {
+ return 41;
+}
+
+//--- b.cppm
+export module B;
+import A;
+
+export int b() {
+ return a() + 1;
+}
+
+//--- main1.cpp
+import A;
+
+int main() {
+ return a();
+}
+
+// Test again for the case where the BMI is first loaded correctly
+// RUN: not %clang_cc1 -std=c++20 main2.cpp-fmodule-file=B=b.pcm \
+// RUN: -fmodule-file=A=b.pcm
+
+//--- main2.cpp
+import B;
+
+int main() {
+ return b();
+}
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