russell@unturf.com
db29a08762
B&W print-friendly diagrams + tinkerpop-0001 + wave-3 proof sections. Squash of 94 local commits onto remote master.
1.3 KiB
1.3 KiB
| id | repo | severity | status | created | patched | patch |
|---|---|---|---|---|---|---|
| llvm-0001 | llvm-project | HIGH | PATCHED | 2026-03-23 | 2026-03-23 | defects/llvm/patch/llvm-0001-globalsmodref-sccset.patch |
Defect
File: lib/Analysis/GlobalsModRef.cpp:570
Pattern: is_contained(vector<CGN*>) in call graph traversal during LTO
Complexity: O(V×E)
Language: C++
Description
During link-time optimization, GlobalsModRef traverses the call graph to determine which globals each function may modify. At line 570, is_contained (a linear search over a SmallVector<CallGraphNode*>) is used to check whether a node has already been visited. Since this check is performed for every edge E in a graph with V nodes, the total traversal cost is O(V×E), which is particularly impactful during LTO over large codebases.
Fix
Replace: is_contained(visited, node)
With: visitedSet.count(node)
Data structure change: SmallVector<CallGraphNode*> visited → DenseSet<CallGraphNode*> visitedSet
Work required
- Patch in
defects/llvm/patch/ - Unit test — asserts exact operation counts before/after (in
defects/llvm/unit/) - Integration test (in
defects/llvm/integration/) - Benchmark — before/after on V=100,200,400,800 (in
defects/llvm/bench/) - White paper section