https://github.com/bulbazord created
https://github.com/llvm/llvm-project/pull/147396
Iteration by index is not thread-safe with PathMapingList's design. Instead, we
can expose a `ForEach` method that grabs the PathMappingList's lock before the
callback.
There is a potential pitfall here where the callback tries to call another
PathMappingList method (causing a deadlock), but that seems a little easier to
debug than the PathMappingList getting updated in the middle of a loop
somewhere.
>From e58ab432e05c870ee760c60053bc3291dce8735a Mon Sep 17 00:00:00 2001
From: Alex Langford <alangf...@apple.com>
Date: Mon, 7 Jul 2025 11:53:45 -0700
Subject: [PATCH] [lldb] Replace PathMappingList::GetPathsAtIndex with
thread-safe alternative
Iteration by index is not thread-safe with PathMapingList's design.
Instead, we can expose a `ForEach` method that grabs the
PathMappingList's lock before the callback.
There is a potential pitfall here where the callback tries to call
another PathMappingList method (causing a deadlock), but that seems a
little to debug than the PathMappingList getting updated in the middle
of a loop somewhere.
---
lldb/include/lldb/Target/PathMappingList.h | 6 ++++--
lldb/source/Commands/CommandObjectTarget.cpp | 20 +++++++++++---------
lldb/source/Target/PathMappingList.cpp | 13 +++++--------
3 files changed, 20 insertions(+), 19 deletions(-)
diff --git a/lldb/include/lldb/Target/PathMappingList.h
b/lldb/include/lldb/Target/PathMappingList.h
index 2cf9569358f52..02fee4d8ed45f 100644
--- a/lldb/include/lldb/Target/PathMappingList.h
+++ b/lldb/include/lldb/Target/PathMappingList.h
@@ -61,8 +61,10 @@ class PathMappingList {
return m_pairs.size();
}
- bool GetPathsAtIndex(uint32_t idx, ConstString &path,
- ConstString &new_path) const;
+ /// Invokes callback for each pair of paths in the list. The callback can
+ /// return false to immediately stop iteration.
+ void
+ ForEach(std::function<bool(llvm::StringRef, llvm::StringRef)> callback)
const;
void Insert(llvm::StringRef path, llvm::StringRef replacement,
uint32_t insert_idx, bool notify);
diff --git a/lldb/source/Commands/CommandObjectTarget.cpp
b/lldb/source/Commands/CommandObjectTarget.cpp
index fe421adfe8709..e8ebcb8008ff9 100644
--- a/lldb/source/Commands/CommandObjectTarget.cpp
+++ b/lldb/source/Commands/CommandObjectTarget.cpp
@@ -1139,15 +1139,17 @@ class CommandObjectTargetModulesSearchPathsInsert :
public CommandObjectParsed {
Target *target = m_exe_ctx.GetTargetPtr();
const PathMappingList &list = target->GetImageSearchPathList();
- const size_t num = list.GetSize();
- ConstString old_path, new_path;
- for (size_t i = 0; i < num; ++i) {
- if (!list.GetPathsAtIndex(i, old_path, new_path))
- break;
- StreamString strm;
- strm << old_path << " -> " << new_path;
- request.TryCompleteCurrentArg(std::to_string(i), strm.GetString());
- }
+
+ StreamString strm;
+ size_t index = 0;
+ list.ForEach([&](llvm::StringRef orig_path, llvm::StringRef remap_path) {
+ strm << orig_path << " -> " << remap_path;
+ request.TryCompleteCurrentArg(std::to_string(index), strm.GetString());
+
+ index++;
+ strm.Clear();
+ return true;
+ });
}
protected:
diff --git a/lldb/source/Target/PathMappingList.cpp
b/lldb/source/Target/PathMappingList.cpp
index 0465b4280bbb1..d8dd9dde7a307 100644
--- a/lldb/source/Target/PathMappingList.cpp
+++ b/lldb/source/Target/PathMappingList.cpp
@@ -346,15 +346,12 @@ PathMappingList::FindIteratorForPath(ConstString path) {
return pos;
}
-bool PathMappingList::GetPathsAtIndex(uint32_t idx, ConstString &path,
- ConstString &new_path) const {
+void PathMappingList::ForEach(
+ std::function<bool(llvm::StringRef, llvm::StringRef)> callback) const {
std::lock_guard<std::mutex> lock(m_pairs_mutex);
- if (idx < m_pairs.size()) {
- path = m_pairs[idx].first;
- new_path = m_pairs[idx].second;
- return true;
- }
- return false;
+ for (const auto &[original, replacement] : m_pairs)
+ if (!callback(original, replacement))
+ break;
}
uint32_t
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
