yinghuitan created this revision.
yinghuitan added reviewers: clayborg, labath, jingham, jdoerfert, JDevlieghere,
kusmour, GeorgeHuyubo.
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This patch fixes a 32bit integer overflow in lldb-vscode.
The current implementation of frame_id does `(thread_index << 19 |
frame_index)`. Since thread_index is a 32 bit integer this leaves only 32 - 19
== 13 bits available for the thread_index. As a result, lldb-vscode can only
handle 2^13 == 8192 threads. Normally, this would be sufficient, but we have
seen crazy process having +12000 threads, causing the frame_id algorithm above
to integer overflow during casting.
The patch fixes the overflow by up casting to 64 bit integer first before bit
shifiting.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D156375
Files:
lldb/tools/lldb-vscode/LLDBUtils.cpp
Index: lldb/tools/lldb-vscode/LLDBUtils.cpp
===================================================================
--- lldb/tools/lldb-vscode/LLDBUtils.cpp
+++ lldb/tools/lldb-vscode/LLDBUtils.cpp
@@ -79,8 +79,8 @@
}
int64_t MakeVSCodeFrameID(lldb::SBFrame &frame) {
- return (int64_t)(frame.GetThread().GetIndexID() << THREAD_INDEX_SHIFT |
- frame.GetFrameID());
+ return ((int64_t)frame.GetThread().GetIndexID() << THREAD_INDEX_SHIFT) |
+ frame.GetFrameID();
}
} // namespace lldb_vscode
Index: lldb/tools/lldb-vscode/LLDBUtils.cpp
===================================================================
--- lldb/tools/lldb-vscode/LLDBUtils.cpp
+++ lldb/tools/lldb-vscode/LLDBUtils.cpp
@@ -79,8 +79,8 @@
}
int64_t MakeVSCodeFrameID(lldb::SBFrame &frame) {
- return (int64_t)(frame.GetThread().GetIndexID() << THREAD_INDEX_SHIFT |
- frame.GetFrameID());
+ return ((int64_t)frame.GetThread().GetIndexID() << THREAD_INDEX_SHIFT) |
+ frame.GetFrameID();
}
} // namespace lldb_vscode
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