[clang] Make explicitly-built modules independent of the CWD #164840
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@llvm/pr-subscribers-clang-modules Author: Jan Svoboda (jansvoboda11) ChangesPR #150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string. Full diff: https://github.com/llvm/llvm-project/pull/164840.diff 4 Files Affected:
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 374138fe4cf8f..e3bf0eaa3c391 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -546,14 +546,11 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
std::string CompilerInstance::getSpecificModuleCachePath(StringRef ModuleHash) {
assert(FileMgr && "Specific module cache path requires a FileManager");
- if (getHeaderSearchOpts().ModuleCachePath.empty())
- return "";
-
// Set up the module path, including the hash for the module-creation options.
SmallString<256> SpecificModuleCache;
normalizeModuleCachePath(*FileMgr, getHeaderSearchOpts().ModuleCachePath,
SpecificModuleCache);
- if (!getHeaderSearchOpts().DisableModuleHash)
+ if (!SpecificModuleCache.empty() && !getHeaderSearchOpts().DisableModuleHash)
llvm::sys::path::append(SpecificModuleCache, ModuleHash);
return std::string(SpecificModuleCache);
}
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 238c5e2f2d9a5..65c324c10ca5d 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -2186,6 +2186,8 @@ std::string HeaderSearch::suggestPathToFileForDiagnostics(
void clang::normalizeModuleCachePath(FileManager &FileMgr, StringRef Path,
SmallVectorImpl<char> &NormalizedPath) {
NormalizedPath.assign(Path.begin(), Path.end());
- FileMgr.makeAbsolutePath(NormalizedPath);
- llvm::sys::path::remove_dots(NormalizedPath);
+ if (!NormalizedPath.empty()) {
+ FileMgr.makeAbsolutePath(NormalizedPath);
+ llvm::sys::path::remove_dots(NormalizedPath);
+ }
}
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
index 05d566922a441..42f52d0ff6241 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
@@ -524,13 +524,12 @@ bool initializeScanCompilerInstance(
// Use the dependency scanning optimized file system if requested to do so.
if (DepFS) {
DepFS->resetBypassedPathPrefix();
- if (!ScanInstance.getHeaderSearchOpts().ModuleCachePath.empty()) {
- SmallString<256> ModulesCachePath;
- normalizeModuleCachePath(
- ScanInstance.getFileManager(),
- ScanInstance.getHeaderSearchOpts().ModuleCachePath, ModulesCachePath);
+ SmallString<256> ModulesCachePath;
+ normalizeModuleCachePath(ScanInstance.getFileManager(),
+ ScanInstance.getHeaderSearchOpts().ModuleCachePath,
+ ModulesCachePath);
+ if (!ModulesCachePath.empty())
DepFS->setBypassedPathPrefix(ModulesCachePath);
- }
ScanInstance.setDependencyDirectivesGetter(
std::make_unique<ScanningDependencyDirectivesGetter>(
diff --git a/clang/test/Modules/explicit-build-cwd.c b/clang/test/Modules/explicit-build-cwd.c
new file mode 100644
index 0000000000000..af8b74361d685
--- /dev/null
+++ b/clang/test/Modules/explicit-build-cwd.c
@@ -0,0 +1,17 @@
+// This test checks that explicitly building the same module from different
+// working directories results in the same PCM contents.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: mkdir %t/one
+// RUN: mkdir %t/two
+
+//--- module.modulemap
+module M { header "M.h" }
+
+//--- M.h
+
+// RUN: cd %t/one && %clang_cc1 -fmodules -emit-module %t/module.modulemap -fmodule-name=M -o %t/M_one.pcm
+// RUN: cd %t/two && %clang_cc1 -fmodules -emit-module %t/module.modulemap -fmodule-name=M -o %t/M_two.pcm
+
+// RUN: diff %t/M_one.pcm %t/M_two.pcm
|
|
@llvm/pr-subscribers-clang Author: Jan Svoboda (jansvoboda11) ChangesPR #150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string. Full diff: https://github.com/llvm/llvm-project/pull/164840.diff 4 Files Affected:
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 374138fe4cf8f..e3bf0eaa3c391 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -546,14 +546,11 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
std::string CompilerInstance::getSpecificModuleCachePath(StringRef ModuleHash) {
assert(FileMgr && "Specific module cache path requires a FileManager");
- if (getHeaderSearchOpts().ModuleCachePath.empty())
- return "";
-
// Set up the module path, including the hash for the module-creation options.
SmallString<256> SpecificModuleCache;
normalizeModuleCachePath(*FileMgr, getHeaderSearchOpts().ModuleCachePath,
SpecificModuleCache);
- if (!getHeaderSearchOpts().DisableModuleHash)
+ if (!SpecificModuleCache.empty() && !getHeaderSearchOpts().DisableModuleHash)
llvm::sys::path::append(SpecificModuleCache, ModuleHash);
return std::string(SpecificModuleCache);
}
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 238c5e2f2d9a5..65c324c10ca5d 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -2186,6 +2186,8 @@ std::string HeaderSearch::suggestPathToFileForDiagnostics(
void clang::normalizeModuleCachePath(FileManager &FileMgr, StringRef Path,
SmallVectorImpl<char> &NormalizedPath) {
NormalizedPath.assign(Path.begin(), Path.end());
- FileMgr.makeAbsolutePath(NormalizedPath);
- llvm::sys::path::remove_dots(NormalizedPath);
+ if (!NormalizedPath.empty()) {
+ FileMgr.makeAbsolutePath(NormalizedPath);
+ llvm::sys::path::remove_dots(NormalizedPath);
+ }
}
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
index 05d566922a441..42f52d0ff6241 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScannerImpl.cpp
@@ -524,13 +524,12 @@ bool initializeScanCompilerInstance(
// Use the dependency scanning optimized file system if requested to do so.
if (DepFS) {
DepFS->resetBypassedPathPrefix();
- if (!ScanInstance.getHeaderSearchOpts().ModuleCachePath.empty()) {
- SmallString<256> ModulesCachePath;
- normalizeModuleCachePath(
- ScanInstance.getFileManager(),
- ScanInstance.getHeaderSearchOpts().ModuleCachePath, ModulesCachePath);
+ SmallString<256> ModulesCachePath;
+ normalizeModuleCachePath(ScanInstance.getFileManager(),
+ ScanInstance.getHeaderSearchOpts().ModuleCachePath,
+ ModulesCachePath);
+ if (!ModulesCachePath.empty())
DepFS->setBypassedPathPrefix(ModulesCachePath);
- }
ScanInstance.setDependencyDirectivesGetter(
std::make_unique<ScanningDependencyDirectivesGetter>(
diff --git a/clang/test/Modules/explicit-build-cwd.c b/clang/test/Modules/explicit-build-cwd.c
new file mode 100644
index 0000000000000..af8b74361d685
--- /dev/null
+++ b/clang/test/Modules/explicit-build-cwd.c
@@ -0,0 +1,17 @@
+// This test checks that explicitly building the same module from different
+// working directories results in the same PCM contents.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: mkdir %t/one
+// RUN: mkdir %t/two
+
+//--- module.modulemap
+module M { header "M.h" }
+
+//--- M.h
+
+// RUN: cd %t/one && %clang_cc1 -fmodules -emit-module %t/module.modulemap -fmodule-name=M -o %t/M_one.pcm
+// RUN: cd %t/two && %clang_cc1 -fmodules -emit-module %t/module.modulemap -fmodule-name=M -o %t/M_two.pcm
+
+// RUN: diff %t/M_one.pcm %t/M_two.pcm
|
benlangmuir
approved these changes
Oct 23, 2025
jansvoboda11
added a commit
to swiftlang/llvm-project
that referenced
this pull request
Oct 23, 2025
…4840) PR llvm#150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string.
dvbuka
pushed a commit
to dvbuka/llvm-project
that referenced
this pull request
Oct 27, 2025
…4840) PR llvm#150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string.
Lukacma
pushed a commit
to Lukacma/llvm-project
that referenced
this pull request
Oct 29, 2025
…4840) PR llvm#150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string.
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PR #150123 changed how we normalize the modules cache path. Unfortunately, empty path would get normalized to the current working directory. This means that even explicitly-built PCMs that don't rely on the CWD now embed it, leading to surprising behavior. This PR fixes that by normalizing an empty modules cache path to an empty string.