[clang] [clang] Delay normalization of `-fmodules-cache-path` (PR #150123)
Jan Svoboda via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 10 08:49:01 PDT 2025
https://github.com/jansvoboda11 updated https://github.com/llvm/llvm-project/pull/150123
>From a3221d4adcacb3cb53edf785a9b21028188797f5 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Tue, 22 Jul 2025 14:46:09 -0700
Subject: [PATCH 1/4] [clang] Delay normalization of `-fmodules-cache-path`
---
clang/include/clang/Driver/Options.td | 3 +-
clang/lib/Frontend/CompilerInstance.cpp | 7 +-
clang/lib/Frontend/CompilerInvocation.cpp | 20 +----
clang/lib/Serialization/ASTWriter.cpp | 77 +++++++------------
...dules-cache-path-canonicalization-output.c | 18 +++++
5 files changed, 55 insertions(+), 70 deletions(-)
create mode 100644 clang/test/Modules/modules-cache-path-canonicalization-output.c
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 49e917a6a0786..40486e3b169aa 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3281,7 +3281,8 @@ defm declspec : BoolOption<"f", "declspec",
def fmodules_cache_path : Joined<["-"], "fmodules-cache-path=">, Group<i_Group>,
Flags<[]>, Visibility<[ClangOption, CC1Option]>,
MetaVarName<"<directory>">,
- HelpText<"Specify the module cache path">;
+ HelpText<"Specify the module cache path">,
+ MarshallingInfoString<HeaderSearchOpts<"ModuleCachePath">>;
def fmodules_user_build_path : Separate<["-"], "fmodules-user-build-path">, Group<i_Group>,
Flags<[]>, Visibility<[ClangOption, CC1Option]>,
MetaVarName<"<directory>">,
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index b2c566f44c27f..24222dfe70a8e 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -548,9 +548,14 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
}
std::string CompilerInstance::getSpecificModuleCachePath(StringRef ModuleHash) {
+ if (getHeaderSearchOpts().ModuleCachePath.empty())
+ return "";
+
// Set up the module path, including the hash for the module-creation options.
SmallString<256> SpecificModuleCache(getHeaderSearchOpts().ModuleCachePath);
- if (!SpecificModuleCache.empty() && !getHeaderSearchOpts().DisableModuleHash)
+ FileMgr->makeAbsolutePath(SpecificModuleCache);
+ llvm::sys::path::remove_dots(SpecificModuleCache);
+ if (!getHeaderSearchOpts().DisableModuleHash)
llvm::sys::path::append(SpecificModuleCache, ModuleHash);
return std::string(SpecificModuleCache);
}
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 8411d00cc7812..931766db4b0c8 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3315,9 +3315,6 @@ static void GenerateHeaderSearchArgs(const HeaderSearchOptions &Opts,
if (Opts.UseLibcxx)
GenerateArg(Consumer, OPT_stdlib_EQ, "libc++");
- if (!Opts.ModuleCachePath.empty())
- GenerateArg(Consumer, OPT_fmodules_cache_path, Opts.ModuleCachePath);
-
for (const auto &File : Opts.PrebuiltModuleFiles)
GenerateArg(Consumer, OPT_fmodule_file, File.first + "=" + File.second);
@@ -3420,8 +3417,7 @@ static void GenerateHeaderSearchArgs(const HeaderSearchOptions &Opts,
}
static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
- DiagnosticsEngine &Diags,
- const std::string &WorkingDir) {
+ DiagnosticsEngine &Diags) {
unsigned NumErrorsBefore = Diags.getNumErrors();
HeaderSearchOptions *HeaderSearchOpts = &Opts;
@@ -3434,17 +3430,6 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
if (const Arg *A = Args.getLastArg(OPT_stdlib_EQ))
Opts.UseLibcxx = (strcmp(A->getValue(), "libc++") == 0);
- // Canonicalize -fmodules-cache-path before storing it.
- SmallString<128> P(Args.getLastArgValue(OPT_fmodules_cache_path));
- if (!(P.empty() || llvm::sys::path::is_absolute(P))) {
- if (WorkingDir.empty())
- llvm::sys::fs::make_absolute(P);
- else
- llvm::sys::fs::make_absolute(WorkingDir, P);
- }
- llvm::sys::path::remove_dots(P);
- Opts.ModuleCachePath = std::string(P);
-
// Only the -fmodule-file=<name>=<file> form.
for (const auto *A : Args.filtered(OPT_fmodule_file)) {
StringRef Val = A->getValue();
@@ -5021,8 +5006,7 @@ bool CompilerInvocation::CreateFromArgsImpl(
InputKind DashX = Res.getFrontendOpts().DashX;
ParseTargetArgs(Res.getTargetOpts(), Args, Diags);
llvm::Triple T(Res.getTargetOpts().Triple);
- ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), Args, Diags,
- Res.getFileSystemOpts().WorkingDir);
+ ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), Args, Diags);
if (Res.getFrontendOpts().GenReducedBMI ||
Res.getFrontendOpts().ProgramAction ==
frontend::GenerateReducedModuleInterface ||
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 293b67aac0219..29e42b20b16eb 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1185,51 +1185,36 @@ static bool cleanPathForOutput(FileManager &FileMgr,
return Changed | llvm::sys::path::remove_dots(Path);
}
-/// Adjusts the given filename to only write out the portion of the
-/// filename that is not part of the system root directory.
+/// Adjusts the given filename to only write out the portion of the filename
+/// that is not part of the base directory.
///
/// \param Filename the file name to adjust.
///
-/// \param BaseDir When non-NULL, the PCH file is a relocatable AST file and
-/// the returned filename will be adjusted by this root directory.
+/// \param BasePath When not empty, the AST file is relocatable and the returned
+/// filename will be adjusted to be relative to this path.
///
-/// \returns either the original filename (if it needs no adjustment) or the
-/// adjusted filename (which points into the @p Filename parameter).
-static const char *
-adjustFilenameForRelocatableAST(const char *Filename, StringRef BaseDir) {
- assert(Filename && "No file name to adjust?");
-
- if (BaseDir.empty())
- return Filename;
-
- // Verify that the filename and the system root have the same prefix.
- unsigned Pos = 0;
- for (; Filename[Pos] && Pos < BaseDir.size(); ++Pos)
- if (Filename[Pos] != BaseDir[Pos])
- return Filename; // Prefixes don't match.
-
- // We hit the end of the filename before we hit the end of the system root.
- if (!Filename[Pos])
- return Filename;
-
- // If there's not a path separator at the end of the base directory nor
- // immediately after it, then this isn't within the base directory.
- if (!llvm::sys::path::is_separator(Filename[Pos])) {
- if (!llvm::sys::path::is_separator(BaseDir.back()))
- return Filename;
- } else {
- // If the file name has a '/' at the current position, skip over the '/'.
- // We distinguish relative paths from absolute paths by the
- // absence of '/' at the beginning of relative paths.
- //
- // FIXME: This is wrong. We distinguish them by asking if the path is
- // absolute, which isn't the same thing. And there might be multiple '/'s
- // in a row. Use a better mechanism to indicate whether we have emitted an
- // absolute or relative path.
- ++Pos;
- }
+/// \returns true when \c Filename was adjusted, false otherwise.
+static bool adjustFilenameForRelocatableAST(SmallVectorImpl<char> &Filename,
+ StringRef BasePath) {
+ auto FileIt = llvm::sys::path::begin({Filename.begin(), Filename.size()});
+ auto FileEnd = llvm::sys::path::end({Filename.begin(), Filename.size()});
+
+ auto BaseIt = llvm::sys::path::begin(BasePath);
+ auto BaseEnd = llvm::sys::path::end(BasePath);
+
+ for (; FileIt != FileEnd && BaseIt != BaseEnd; ++FileIt, ++BaseIt)
+ if (*FileIt != *BaseIt)
+ return false;
+
+ if (FileIt == FileEnd)
+ return false;
+
+ SmallString<128> Clean;
+ for (; FileIt != FileEnd; ++FileIt)
+ llvm::sys::path::append(Clean, *FileIt);
- return Filename + Pos;
+ Filename.assign(Clean.begin(), Clean.end());
+ return true;
}
std::pair<ASTFileSignature, ASTFileSignature>
@@ -1712,7 +1697,7 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, StringRef isysroot) {
AddString(HSOpts.Sysroot, Record);
AddString(HSOpts.ResourceDir, Record);
- AddString(HSOpts.ModuleCachePath, Record);
+ AddPath(HSOpts.ModuleCachePath, Record);
AddString(HSOpts.ModuleUserBuildPath, Record);
Record.push_back(HSOpts.DisableModuleHash);
Record.push_back(HSOpts.ImplicitModuleMaps);
@@ -5342,16 +5327,8 @@ bool ASTWriter::PreparePathForOutput(SmallVectorImpl<char> &Path) {
return false;
bool Changed = cleanPathForOutput(PP->getFileManager(), Path);
-
- // Remove a prefix to make the path relative, if relevant.
- const char *PathBegin = Path.data();
- const char *PathPtr =
- adjustFilenameForRelocatableAST(PathBegin, BaseDirectory);
- if (PathPtr != PathBegin) {
- Path.erase(Path.begin(), Path.begin() + (PathPtr - PathBegin));
+ if (adjustFilenameForRelocatableAST(Path, BaseDirectory))
Changed = true;
- }
-
return Changed;
}
diff --git a/clang/test/Modules/modules-cache-path-canonicalization-output.c b/clang/test/Modules/modules-cache-path-canonicalization-output.c
new file mode 100644
index 0000000000000..ad71b69e5299e
--- /dev/null
+++ b/clang/test/Modules/modules-cache-path-canonicalization-output.c
@@ -0,0 +1,18 @@
+// This checks that implicitly-built modules produce identical PCM
+// files regardless of the spelling of the same module cache path.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fsyntax-only %t/tu.c \
+// RUN: -fmodules-cache-path=%t/cache -fdisable-module-hash
+// RUN: mv %t/cache/M.pcm %t/M.pcm
+// RUN: %clang_cc1 -fmodules -fimplicit-module-maps -fsyntax-only %t/tu.c \
+// RUN: -fmodules-cache-path=%t/./cache -fdisable-module-hash
+// RUN: diff %t/./cache/M.pcm %t/M.pcm
+
+//--- tu.c
+#include "M.h"
+//--- M.h
+//--- module.modulemap
+module M { header "M.h" }
>From 43623d3a57e1e5a421f38cd058e01c01cbb3040b Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Tue, 9 Sep 2025 15:25:54 -0700
Subject: [PATCH 2/4] Fix Windows CI
---
.../DependencyScanning/DependencyScanningWorker.cpp | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
index b2b61de790e8f..e3fb9ae351e60 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -448,9 +448,10 @@ class DependencyScanningAction {
// Use the dependency scanning optimized file system if requested to do so.
if (DepFS) {
- StringRef ModulesCachePath =
- ScanInstance.getHeaderSearchOpts().ModuleCachePath;
-
+ SmallString<256> ModulesCachePath(
+ ScanInstance.getHeaderSearchOpts().ModuleCachePath);
+ FileMgr->makeAbsolutePath(ModulesCachePath);
+ llvm::sys::path::remove_dots(ModulesCachePath);
DepFS->resetBypassedPathPrefix();
if (!ModulesCachePath.empty())
DepFS->setBypassedPathPrefix(ModulesCachePath);
>From 0e174e97999fc759a127480950cd007078124a22 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Tue, 9 Sep 2025 15:28:40 -0700
Subject: [PATCH 3/4] Minimize ASTWriter diff
---
clang/lib/Serialization/ASTWriter.cpp | 81 ++++++++++++++++++---------
1 file changed, 54 insertions(+), 27 deletions(-)
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 29e42b20b16eb..ec308ffcd4de9 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1185,36 +1185,51 @@ static bool cleanPathForOutput(FileManager &FileMgr,
return Changed | llvm::sys::path::remove_dots(Path);
}
-/// Adjusts the given filename to only write out the portion of the filename
-/// that is not part of the base directory.
+/// Adjusts the given filename to only write out the portion of the
+/// filename that is not part of the system root directory.
///
/// \param Filename the file name to adjust.
///
-/// \param BasePath When not empty, the AST file is relocatable and the returned
-/// filename will be adjusted to be relative to this path.
+/// \param BaseDir When non-NULL, the PCH file is a relocatable AST file and
+/// the returned filename will be adjusted by this root directory.
///
-/// \returns true when \c Filename was adjusted, false otherwise.
-static bool adjustFilenameForRelocatableAST(SmallVectorImpl<char> &Filename,
- StringRef BasePath) {
- auto FileIt = llvm::sys::path::begin({Filename.begin(), Filename.size()});
- auto FileEnd = llvm::sys::path::end({Filename.begin(), Filename.size()});
-
- auto BaseIt = llvm::sys::path::begin(BasePath);
- auto BaseEnd = llvm::sys::path::end(BasePath);
-
- for (; FileIt != FileEnd && BaseIt != BaseEnd; ++FileIt, ++BaseIt)
- if (*FileIt != *BaseIt)
- return false;
-
- if (FileIt == FileEnd)
- return false;
-
- SmallString<128> Clean;
- for (; FileIt != FileEnd; ++FileIt)
- llvm::sys::path::append(Clean, *FileIt);
+/// \returns either the original filename (if it needs no adjustment) or the
+/// adjusted filename (which points into the @p Filename parameter).
+static const char *
+adjustFilenameForRelocatableAST(const char *Filename, StringRef BaseDir) {
+ assert(Filename && "No file name to adjust?");
+
+ if (BaseDir.empty())
+ return Filename;
+
+ // Verify that the filename and the system root have the same prefix.
+ unsigned Pos = 0;
+ for (; Filename[Pos] && Pos < BaseDir.size(); ++Pos)
+ if (Filename[Pos] != BaseDir[Pos])
+ return Filename; // Prefixes don't match.
+
+ // We hit the end of the filename before we hit the end of the system root.
+ if (!Filename[Pos])
+ return Filename;
+
+ // If there's not a path separator at the end of the base directory nor
+ // immediately after it, then this isn't within the base directory.
+ if (!llvm::sys::path::is_separator(Filename[Pos])) {
+ if (!llvm::sys::path::is_separator(BaseDir.back()))
+ return Filename;
+ } else {
+ // If the file name has a '/' at the current position, skip over the '/'.
+ // We distinguish relative paths from absolute paths by the
+ // absence of '/' at the beginning of relative paths.
+ //
+ // FIXME: This is wrong. We distinguish them by asking if the path is
+ // absolute, which isn't the same thing. And there might be multiple '/'s
+ // in a row. Use a better mechanism to indicate whether we have emitted an
+ // absolute or relative path.
+ ++Pos;
+ }
- Filename.assign(Clean.begin(), Clean.end());
- return true;
+ return Filename + Pos;
}
std::pair<ASTFileSignature, ASTFileSignature>
@@ -1697,7 +1712,11 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, StringRef isysroot) {
AddString(HSOpts.Sysroot, Record);
AddString(HSOpts.ResourceDir, Record);
- AddPath(HSOpts.ModuleCachePath, Record);
+
+ SmallString<256> ModuleCachePath(HSOpts.ModuleCachePath);
+ (void)cleanPathForOutput(PP.getFileManager(), ModuleCachePath);
+ AddString(ModuleCachePath, Record);
+
AddString(HSOpts.ModuleUserBuildPath, Record);
Record.push_back(HSOpts.DisableModuleHash);
Record.push_back(HSOpts.ImplicitModuleMaps);
@@ -5327,8 +5346,16 @@ bool ASTWriter::PreparePathForOutput(SmallVectorImpl<char> &Path) {
return false;
bool Changed = cleanPathForOutput(PP->getFileManager(), Path);
- if (adjustFilenameForRelocatableAST(Path, BaseDirectory))
+
+ // Remove a prefix to make the path relative, if relevant.
+ const char *PathBegin = Path.data();
+ const char *PathPtr =
+ adjustFilenameForRelocatableAST(PathBegin, BaseDirectory);
+ if (PathPtr != PathBegin) {
+ Path.erase(Path.begin(), Path.begin() + (PathPtr - PathBegin));
Changed = true;
+ }
+
return Changed;
}
>From 6e845bba063d95ae087eaa6686cbbf783556b108 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Wed, 10 Sep 2025 08:48:47 -0700
Subject: [PATCH 4/4] Centralize module cache normalization
---
clang/include/clang/Frontend/CompilerInstance.h | 2 ++
clang/lib/Frontend/CompilerInstance.cpp | 16 +++++++++++++---
clang/lib/Serialization/ASTWriter.cpp | 10 +++++-----
.../DependencyScanningWorker.cpp | 6 ++----
4 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/clang/include/clang/Frontend/CompilerInstance.h b/clang/include/clang/Frontend/CompilerInstance.h
index 64ebb70a6a24c..4254dbbc4fce0 100644
--- a/clang/include/clang/Frontend/CompilerInstance.h
+++ b/clang/include/clang/Frontend/CompilerInstance.h
@@ -699,6 +699,8 @@ class CompilerInstance : public ModuleLoader {
GetDependencyDirectives = std::move(Getter);
}
+ static SmallString<256> normalizeModuleCachePath(FileManager &FileMgr,
+ StringRef ModuleCachePath);
std::string getSpecificModuleCachePath(StringRef ModuleHash);
std::string getSpecificModuleCachePath() {
return getSpecificModuleCachePath(getInvocation().getModuleHash());
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 24222dfe70a8e..995ecbd4a6e79 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -547,14 +547,24 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
PP->setDependencyDirectivesGetter(*GetDependencyDirectives);
}
+SmallString<256>
+CompilerInstance::normalizeModuleCachePath(FileManager &FileMgr,
+ StringRef ModuleCachePath) {
+ SmallString<256> NormalizedModuleCachePath(ModuleCachePath);
+ FileMgr.makeAbsolutePath(NormalizedModuleCachePath);
+ llvm::sys::path::remove_dots(NormalizedModuleCachePath);
+ return NormalizedModuleCachePath;
+}
+
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(getHeaderSearchOpts().ModuleCachePath);
- FileMgr->makeAbsolutePath(SpecificModuleCache);
- llvm::sys::path::remove_dots(SpecificModuleCache);
+ SmallString<256> SpecificModuleCache =
+ normalizeModuleCachePath(*FileMgr, getHeaderSearchOpts().ModuleCachePath);
if (!getHeaderSearchOpts().DisableModuleHash)
llvm::sys::path::append(SpecificModuleCache, ModuleHash);
return std::string(SpecificModuleCache);
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index ec308ffcd4de9..604ce113cbc97 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -57,6 +57,7 @@
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TargetOptions.h"
#include "clang/Basic/Version.h"
+#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/HeaderSearchOptions.h"
#include "clang/Lex/MacroInfo.h"
@@ -1710,13 +1711,12 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, StringRef isysroot) {
const HeaderSearchOptions &HSOpts =
PP.getHeaderSearchInfo().getHeaderSearchOpts();
+ auto HSOpts_ModuleCachePath = CompilerInstance::normalizeModuleCachePath(
+ PP.getFileManager(), HSOpts.ModuleCachePath);
+
AddString(HSOpts.Sysroot, Record);
AddString(HSOpts.ResourceDir, Record);
-
- SmallString<256> ModuleCachePath(HSOpts.ModuleCachePath);
- (void)cleanPathForOutput(PP.getFileManager(), ModuleCachePath);
- AddString(ModuleCachePath, Record);
-
+ AddString(HSOpts_ModuleCachePath, Record);
AddString(HSOpts.ModuleUserBuildPath, Record);
Record.push_back(HSOpts.DisableModuleHash);
Record.push_back(HSOpts.ImplicitModuleMaps);
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
index e3fb9ae351e60..a2a6776b89fd6 100644
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -448,10 +448,8 @@ class DependencyScanningAction {
// Use the dependency scanning optimized file system if requested to do so.
if (DepFS) {
- SmallString<256> ModulesCachePath(
- ScanInstance.getHeaderSearchOpts().ModuleCachePath);
- FileMgr->makeAbsolutePath(ModulesCachePath);
- llvm::sys::path::remove_dots(ModulesCachePath);
+ auto ModulesCachePath = CompilerInstance::normalizeModuleCachePath(
+ *FileMgr, ScanInstance.getHeaderSearchOpts().ModuleCachePath);
DepFS->resetBypassedPathPrefix();
if (!ModulesCachePath.empty())
DepFS->setBypassedPathPrefix(ModulesCachePath);
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