llvm/clang/unittests/Serialization/ModuleCacheTest.cpp
Ben Barham 766a08df12 [Frontend] Only compile modules if not already finalized
It was possible to re-add a module to a shared in-memory module cache
when search paths are changed. This can eventually cause a crash if the
original module is referenced after this occurs.
  1. Module A depends on B
  2. B exists in two paths C and D
  3. First run only has C on the search path, finds A and B and loads
     them
  4. Second run adds D to the front of the search path. A is loaded and
     contains a reference to the already compiled module from C. But
     searching finds the module from D instead, causing a mismatch
  5. B and the modules that depend on it are considered out of date and
     thus rebuilt
  6. The recompiled module A is added to the in-memory cache, freeing
     the previously inserted one

This can never occur from a regular clang process, but is very easy to
do through the API - whether through the use of a shared case or just
running multiple compilations from a single `CompilerInstance`. Update
the compilation to return early if a module is already finalized so that
the pre-condition in the in-memory module cache holds.

Resolves rdar://78180255

Differential Revision: https://reviews.llvm.org/D105328
2021-07-15 18:27:08 -07:00

179 lines
6.3 KiB
C++

//===- unittests/Serialization/ModuleCacheTest.cpp - CI tests -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "clang/Basic/FileManager.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Frontend/FrontendActions.h"
#include "clang/Lex/HeaderSearch.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/raw_ostream.h"
#include "gtest/gtest.h"
using namespace llvm;
using namespace clang;
namespace {
class ModuleCacheTest : public ::testing::Test {
void SetUp() override {
ASSERT_FALSE(sys::fs::createUniqueDirectory("modulecache-test", TestDir));
ModuleCachePath = SmallString<256>(TestDir);
sys::path::append(ModuleCachePath, "mcp");
ASSERT_FALSE(sys::fs::create_directories(ModuleCachePath));
}
void TearDown() override { sys::fs::remove_directories(TestDir); }
public:
SmallString<256> TestDir;
SmallString<256> ModuleCachePath;
void addFile(StringRef Path, StringRef Contents) {
ASSERT_FALSE(sys::path::is_absolute(Path));
SmallString<256> AbsPath(TestDir);
sys::path::append(AbsPath, Path);
std::error_code EC;
ASSERT_FALSE(
sys::fs::create_directories(llvm::sys::path::parent_path(AbsPath)));
llvm::raw_fd_ostream OS(AbsPath, EC);
ASSERT_FALSE(EC);
OS << Contents;
}
void addDuplicateFrameworks() {
addFile("test.m", R"cpp(
@import Top;
)cpp");
addFile("frameworks/Top.framework/Headers/top.h", R"cpp(
@import M;
)cpp");
addFile("frameworks/Top.framework/Modules/module.modulemap", R"cpp(
framework module Top [system] {
header "top.h"
export *
}
)cpp");
addFile("frameworks/M.framework/Headers/m.h", R"cpp(
void foo();
)cpp");
addFile("frameworks/M.framework/Modules/module.modulemap", R"cpp(
framework module M [system] {
header "m.h"
export *
}
)cpp");
addFile("frameworks2/M.framework/Headers/m.h", R"cpp(
void foo();
)cpp");
addFile("frameworks2/M.framework/Modules/module.modulemap", R"cpp(
framework module M [system] {
header "m.h"
export *
}
)cpp");
}
};
TEST_F(ModuleCacheTest, CachedModuleNewPath) {
addDuplicateFrameworks();
SmallString<256> MCPArg("-fmodules-cache-path=");
MCPArg.append(ModuleCachePath);
IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
CompilerInstance::createDiagnostics(new DiagnosticOptions());
// First run should pass with no errors
const char *Args[] = {"clang", "-fmodules", "-Fframeworks",
MCPArg.c_str(), "-working-directory", TestDir.c_str(),
"test.m"};
std::shared_ptr<CompilerInvocation> Invocation =
createInvocationFromCommandLine(Args, Diags);
ASSERT_TRUE(Invocation);
CompilerInstance Instance;
Instance.setDiagnostics(Diags.get());
Instance.setInvocation(Invocation);
SyntaxOnlyAction Action;
ASSERT_TRUE(Instance.ExecuteAction(Action));
ASSERT_FALSE(Diags->hasErrorOccurred());
// Now add `frameworks2` to the search path. `Top.pcm` will have a reference
// to the `M` from `frameworks`, but a search will find the `M` from
// `frameworks2` - causing a mismatch and it to be considered out of date.
//
// Normally this would be fine - `M` and the modules it depends on would be
// rebuilt. However, since we have a shared module cache and thus an already
// finalized `Top`, recompiling `Top` will cause the existing module to be
// removed from the cache, causing possible crashed if it is ever used.
//
// Make sure that an error occurs instead.
const char *Args2[] = {"clang", "-fmodules", "-Fframeworks2",
"-Fframeworks", MCPArg.c_str(), "-working-directory",
TestDir.c_str(), "test.m"};
std::shared_ptr<CompilerInvocation> Invocation2 =
createInvocationFromCommandLine(Args2, Diags);
ASSERT_TRUE(Invocation2);
CompilerInstance Instance2(Instance.getPCHContainerOperations(),
&Instance.getModuleCache());
Instance2.setDiagnostics(Diags.get());
Instance2.setInvocation(Invocation2);
SyntaxOnlyAction Action2;
ASSERT_FALSE(Instance2.ExecuteAction(Action2));
ASSERT_TRUE(Diags->hasErrorOccurred());
}
TEST_F(ModuleCacheTest, CachedModuleNewPathAllowErrors) {
addDuplicateFrameworks();
SmallString<256> MCPArg("-fmodules-cache-path=");
MCPArg.append(ModuleCachePath);
IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
CompilerInstance::createDiagnostics(new DiagnosticOptions());
// First run should pass with no errors
const char *Args[] = {"clang", "-fmodules", "-Fframeworks",
MCPArg.c_str(), "-working-directory", TestDir.c_str(),
"test.m"};
std::shared_ptr<CompilerInvocation> Invocation =
createInvocationFromCommandLine(Args, Diags);
ASSERT_TRUE(Invocation);
CompilerInstance Instance;
Instance.setDiagnostics(Diags.get());
Instance.setInvocation(Invocation);
SyntaxOnlyAction Action;
ASSERT_TRUE(Instance.ExecuteAction(Action));
ASSERT_FALSE(Diags->hasErrorOccurred());
// Same as `CachedModuleNewPath` but while allowing errors. This is a hard
// failure where the module wasn't created, so it should still fail.
const char *Args2[] = {
"clang", "-fmodules", "-Fframeworks2",
"-Fframeworks", MCPArg.c_str(), "-working-directory",
TestDir.c_str(), "-Xclang", "-fallow-pcm-with-compiler-errors",
"test.m"};
std::shared_ptr<CompilerInvocation> Invocation2 =
createInvocationFromCommandLine(Args2, Diags);
ASSERT_TRUE(Invocation2);
CompilerInstance Instance2(Instance.getPCHContainerOperations(),
&Instance.getModuleCache());
Instance2.setDiagnostics(Diags.get());
Instance2.setInvocation(Invocation2);
SyntaxOnlyAction Action2;
ASSERT_FALSE(Instance2.ExecuteAction(Action2));
ASSERT_TRUE(Diags->hasErrorOccurred());
}
} // anonymous namespace