[PATCH] D26537: Fix llvm-symbolizer to correctly sort a symbol array and calculate symbol sizes

[Kuba Brecka via llvm-commits]

kubabrecka created this revision.
kubabrecka added reviewers: aprantl, dvyukov, kcc, rafael.
kubabrecka added subscribers: llvm-commits, zaks.anna.
kubabrecka set the repository for this revision to rL LLVM.

I noticed that llvm-symbolizer gives wrong results sometimes, this was due to incorrect sizes of some symbols.  The reason for that was an incorrectly sorted array in computeSymbolSizes.  The comparison function used subtraction of unsigned types, which is incorrect.  Let's change this to return explicit -1 or 1.


Repository:
  rL LLVM

https://reviews.llvm.org/D26537

Files:
  lib/Object/SymbolSize.cpp


Index: lib/Object/SymbolSize.cpp
===================================================================
--- lib/Object/SymbolSize.cpp
+++ lib/Object/SymbolSize.cpp
@@ -27,8 +27,10 @@
 
 static int compareAddress(const SymEntry *A, const SymEntry *B) {
   if (A->SectionID != B->SectionID)
-    return A->SectionID - B->SectionID;
-  return A->Address - B->Address;
+    return A->SectionID < B->SectionID ? -1 : 1;
+  if (A->Address != B->Address)
+    return A->Address < B->Address ? -1 : 1;
+  return 0;
 }
 
 static unsigned getSectionID(const ObjectFile &O, SectionRef Sec) {


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