[clang-tools-extra] e257c0a - [clang][clangd] Ensure the stack bottom before building AST
Younan Zhang via cfe-commits
cfe-commits at lists.llvm.org
Sat Sep 2 03:53:14 PDT 2023
Author: Younan Zhang
Date: 2023-09-02T18:53:06+08:00
New Revision: e257c0a9190637e44e292271103a13d70bec4b03
URL: https://github.com/llvm/llvm-project/commit/e257c0a9190637e44e292271103a13d70bec4b03
DIFF: https://github.com/llvm/llvm-project/commit/e257c0a9190637e44e292271103a13d70bec4b03.diff
LOG: [clang][clangd] Ensure the stack bottom before building AST
`clang::runWithSufficientStackSpace` requires the address of the
initial stack bottom to prevent potential stack overflows.
In addition, add a fallback to ASTFrontendAction in case any client
forgets to call it when not through CompilerInstance::ExecuteAction,
which is rare.
Fixes https://github.com/clangd/clangd/issues/1745.
Reviewed By: sammccall
Differential Revision: https://reviews.llvm.org/D158967
Added:
clang-tools-extra/clangd/test/infinite-instantiation.test
Modified:
clang-tools-extra/clangd/ClangdServer.cpp
clang-tools-extra/clangd/TUScheduler.cpp
clang-tools-extra/clangd/index/Background.cpp
clang-tools-extra/clangd/tool/ClangdMain.cpp
clang/lib/Frontend/FrontendAction.cpp
Removed:
################################################################################
diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
index 6610961b2202d1..57a4897a85efb1 100644
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -34,6 +34,7 @@
#include "support/MemoryTree.h"
#include "support/ThreadsafeFS.h"
#include "support/Trace.h"
+#include "clang/Basic/Stack.h"
#include "clang/Format/Format.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Tooling/CompilationDatabase.h"
@@ -52,8 +53,8 @@
#include <optional>
#include <string>
#include <type_traits>
-#include <vector>
#include <utility>
+#include <vector>
namespace clang {
namespace clangd {
@@ -112,6 +113,7 @@ struct UpdateIndexCallbacks : public ParsingCallbacks {
FIndex(FIndex),
// shared_ptr extends lifetime
Stdlib(Stdlib)]() mutable {
+ clang::noteBottomOfStack();
IndexFileIn IF;
IF.Symbols = indexStandardLibrary(std::move(CI), Loc, *TFS);
if (Stdlib->isBest(LO))
diff --git a/clang-tools-extra/clangd/TUScheduler.cpp b/clang-tools-extra/clangd/TUScheduler.cpp
index dd2ce16147a5dd..324ba1fc8cb895 100644
--- a/clang-tools-extra/clangd/TUScheduler.cpp
+++ b/clang-tools-extra/clangd/TUScheduler.cpp
@@ -63,6 +63,7 @@
#include "support/ThreadCrashReporter.h"
#include "support/Threading.h"
#include "support/Trace.h"
+#include "clang/Basic/Stack.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "llvm/ADT/FunctionExtras.h"
@@ -464,6 +465,10 @@ class PreambleThread {
}
void run() {
+ // We mark the current as the stack bottom so that clang running on this
+ // thread can notice the stack usage and prevent stack overflow with best
+ // efforts. Same applies to other calls thoughout clangd.
+ clang::noteBottomOfStack();
while (true) {
std::optional<PreambleThrottlerRequest> Throttle;
{
@@ -1383,6 +1388,7 @@ void ASTWorker::startTask(llvm::StringRef Name,
}
void ASTWorker::run() {
+ clang::noteBottomOfStack();
while (true) {
{
std::unique_lock<std::mutex> Lock(Mutex);
@@ -1777,6 +1783,7 @@ void TUScheduler::runWithPreamble(llvm::StringRef Name, PathRef File,
Ctx = Context::current().derive(FileBeingProcessed,
std::string(File)),
Action = std::move(Action), this]() mutable {
+ clang::noteBottomOfStack();
ThreadCrashReporter ScopedReporter([&Name, &Contents, &Command]() {
llvm::errs() << "Signalled during preamble action: " << Name << "\n";
crashDumpCompileCommand(llvm::errs(), Command);
diff --git a/clang-tools-extra/clangd/index/Background.cpp b/clang-tools-extra/clangd/index/Background.cpp
index cbeb74d145401c..5cde4937fee785 100644
--- a/clang-tools-extra/clangd/index/Background.cpp
+++ b/clang-tools-extra/clangd/index/Background.cpp
@@ -30,6 +30,7 @@
#include "support/Trace.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/Stack.h"
#include "clang/Frontend/FrontendAction.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseSet.h"
@@ -108,6 +109,7 @@ BackgroundIndex::BackgroundIndex(
for (unsigned I = 0; I < Opts.ThreadPoolSize; ++I) {
ThreadPool.runAsync("background-worker-" + llvm::Twine(I + 1),
[this, Ctx(Context::current().clone())]() mutable {
+ clang::noteBottomOfStack();
WithContext BGContext(std::move(Ctx));
Queue.work([&] { Rebuilder.idle(); });
});
diff --git a/clang-tools-extra/clangd/test/infinite-instantiation.test b/clang-tools-extra/clangd/test/infinite-instantiation.test
new file mode 100644
index 00000000000000..85a1b656f49086
--- /dev/null
+++ b/clang-tools-extra/clangd/test/infinite-instantiation.test
@@ -0,0 +1,13 @@
+// RUN: cp %s %t.cpp
+// RUN: not clangd -check=%t.cpp 2>&1 | FileCheck -strict-whitespace %s
+
+// CHECK: [template_recursion_depth_exceeded]
+
+template <typename... T>
+constexpr int f(T... args) {
+ return f(0, args...);
+}
+
+int main() {
+ auto i = f();
+}
diff --git a/clang-tools-extra/clangd/tool/ClangdMain.cpp b/clang-tools-extra/clangd/tool/ClangdMain.cpp
index ca5cced197cd24..f656a8c587c653 100644
--- a/clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ b/clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -29,6 +29,7 @@
#include "support/ThreadCrashReporter.h"
#include "support/ThreadsafeFS.h"
#include "support/Trace.h"
+#include "clang/Basic/Stack.h"
#include "clang/Format/Format.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
@@ -710,6 +711,9 @@ enum class ErrorResultCode : int {
};
int clangdMain(int argc, char *argv[]) {
+ // Clang could run on the main thread. e.g., when the flag '-check' or '-sync'
+ // is enabled.
+ clang::noteBottomOfStack();
llvm::InitializeAllTargetInfos();
llvm::sys::PrintStackTraceOnErrorSignal(argv[0]);
llvm::sys::AddSignalHandler(
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index f14557c316ec7a..2da25be1b9c7a2 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -15,6 +15,7 @@
#include "clang/Basic/FileEntry.h"
#include "clang/Basic/LangStandard.h"
#include "clang/Basic/Sarif.h"
+#include "clang/Basic/Stack.h"
#include "clang/Frontend/ASTUnit.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendDiagnostic.h"
@@ -1155,6 +1156,10 @@ void ASTFrontendAction::ExecuteAction() {
CompilerInstance &CI = getCompilerInstance();
if (!CI.hasPreprocessor())
return;
+ // This is a fallback: If the client forgets to invoke this, we mark the
+ // current stack as the bottom. Though not optimal, this could help prevent
+ // stack overflow during deep recursion.
+ clang::noteBottomOfStack();
// FIXME: Move the truncation aspect of this into Sema, we delayed this till
// here so the source manager would be initialized.
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