[llvm] [CodeExtractor] Resolving the Inconsistency of Compiled Binary Files (PR #86464)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: dong jianqiang (dongjianqiang2)

<details>
<summary>Changes</summary>

When the compiler enables ALSR by default, binary inconsistency occurs when the extractCodeRegion function is called. The reason is that the sequence of traversing ExitBlocks containers of the SmallPtrSet type is changed due to randomization of BasicBlock pointers.

---
Full diff: https://github.com/llvm/llvm-project/pull/86464.diff


2 Files Affected:

- (modified) llvm/include/llvm/Transforms/Utils/CodeExtractor.h (+2-1) 
- (modified) llvm/lib/Transforms/Utils/CodeExtractor.cpp (+2-2) 


``````````diff
diff --git a/llvm/include/llvm/Transforms/Utils/CodeExtractor.h b/llvm/include/llvm/Transforms/Utils/CodeExtractor.h
index 27b34ef023db72..7f21067e5487a3 100644
--- a/llvm/include/llvm/Transforms/Utils/CodeExtractor.h
+++ b/llvm/include/llvm/Transforms/Utils/CodeExtractor.h
@@ -18,6 +18,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SetVector.h"
 #include <limits>
+#include <unordered_set>
 
 namespace llvm {
 
@@ -249,7 +250,7 @@ class CodeExtractorAnalysisCache {
                        Instruction *Addr, BasicBlock *ExitBlock) const;
 
     void severSplitPHINodesOfEntry(BasicBlock *&Header);
-    void severSplitPHINodesOfExits(const SmallPtrSetImpl<BasicBlock *> &Exits);
+    void severSplitPHINodesOfExits(const std::unordered_set<BasicBlock *> &Exits);
     void splitReturnBlocks();
 
     Function *constructFunction(const ValueSet &inputs,
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 3191751d92e176..0184c1c996c5a7 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -745,7 +745,7 @@ void CodeExtractor::severSplitPHINodesOfEntry(BasicBlock *&Header) {
 /// and other with remaining incoming blocks; then first PHIs are placed in
 /// outlined region.
 void CodeExtractor::severSplitPHINodesOfExits(
-    const SmallPtrSetImpl<BasicBlock *> &Exits) {
+    const std::unordered_set<BasicBlock *> &Exits) {
   for (BasicBlock *ExitBB : Exits) {
     BasicBlock *NewBB = nullptr;
 
@@ -1751,7 +1751,7 @@ CodeExtractor::extractCodeRegion(const CodeExtractorAnalysisCache &CEAC,
   // Calculate the exit blocks for the extracted region and the total exit
   // weights for each of those blocks.
   DenseMap<BasicBlock *, BlockFrequency> ExitWeights;
-  SmallPtrSet<BasicBlock *, 1> ExitBlocks;
+  std::unordered_set<BasicBlock *> ExitBlocks;
   for (BasicBlock *Block : Blocks) {
     for (BasicBlock *Succ : successors(Block)) {
       if (!Blocks.count(Succ)) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/86464