https://github.com/ellishg created
https://github.com/llvm/llvm-project/pull/90925
Use `fs::equivalent()`, which follows symlinks, to check if two module cache
paths are equivalent. This prevents a PCH error when building from a different
path that is a symlink of the original.
```
error: PCH was compiled with module cache path
'/home/foo/blah/ModuleCache/2IBP1TNT8OR8D', but the path is currently
'/data/users/foo/blah/ModuleCache/2IBP1TNT8OR8D'
1 error generated.
```
>From 4760ebce0ff7725f4bb75f5107f551d867e4db6d Mon Sep 17 00:00:00 2001
From: Ellis Hoag <ellis.sparky.h...@gmail.com>
Date: Thu, 2 May 2024 17:47:38 -0700
Subject: [PATCH] [modules] Accept equivalent module caches from different
symlink
Use `fs::equivalent()`, which follows symlinks, to check if two module cache
paths are equivalent. This prevents a PCH error when building from a different
path that is a symlink of the original.
```
error: PCH was compiled with module cache path
'/home/foo/blah/ModuleCache/2IBP1TNT8OR8D', but the path is currently
'/data/users/foo/blah/ModuleCache/2IBP1TNT8OR8D'
1 error generated.
```
---
clang/lib/Serialization/ASTReader.cpp | 20 +++++++++-----------
clang/test/Modules/module-symlink.m | 11 +++++++++++
2 files changed, 20 insertions(+), 11 deletions(-)
create mode 100644 clang/test/Modules/module-symlink.m
diff --git a/clang/lib/Serialization/ASTReader.cpp
b/clang/lib/Serialization/ASTReader.cpp
index 0ef57a3ea804ef..c20ead8b865692 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -839,17 +839,15 @@ static bool checkHeaderSearchOptions(const
HeaderSearchOptions &HSOpts,
DiagnosticsEngine *Diags,
const LangOptions &LangOpts,
const PreprocessorOptions &PPOpts) {
- if (LangOpts.Modules) {
- if (SpecificModuleCachePath != ExistingModuleCachePath &&
- !PPOpts.AllowPCHWithDifferentModulesCachePath) {
- if (Diags)
- Diags->Report(diag::err_pch_modulecache_mismatch)
- << SpecificModuleCachePath << ExistingModuleCachePath;
- return true;
- }
- }
-
- return false;
+ if (!LangOpts.Modules || PPOpts.AllowPCHWithDifferentModulesCachePath ||
+ SpecificModuleCachePath == ExistingModuleCachePath ||
+ llvm::sys::fs::equivalent(SpecificModuleCachePath,
+ ExistingModuleCachePath))
+ return false;
+ if (Diags)
+ Diags->Report(diag::err_pch_modulecache_mismatch)
+ << SpecificModuleCachePath << ExistingModuleCachePath;
+ return true;
}
bool PCHValidator::ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
diff --git a/clang/test/Modules/module-symlink.m
b/clang/test/Modules/module-symlink.m
new file mode 100644
index 00000000000000..be447449a0e81e
--- /dev/null
+++ b/clang/test/Modules/module-symlink.m
@@ -0,0 +1,11 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t/modules -fmodules
-fimplicit-module-maps -I %S/Inputs -emit-pch -o %t.pch %s -verify
+
+// RUN: ln -s %t/modules %t/modules.symlink
+// RUN: %clang_cc1 -fmodules-cache-path=%t/modules.symlink -fmodules
-fimplicit-module-maps -I %S/Inputs -include-pch %t.pch %s -verify
+
+// expected-no-diagnostics
+
+@import ignored_macros;
+
+struct Point p;
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