[PATCH] D107273: [llvm-objcopy] IHexELFBuilder::addDataSections - fix evaluation ordering static analyzer warning

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: evgeny777, rupprecht, jhenderson.
Herald added subscribers: manas, steakhal, ASDenysPetrov, abrachet, dkrupp, donat.nagy, Szelethus, a.sidorin, baloghadamsoftware, emaste.
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As detailed on https://pvs-studio.com/en/blog/posts/cpp/0771/ and raised on D62583 <https://reviews.llvm.org/D62583>, the SecNo++increment is not guaranteed to occur before the second use of SecNo in the same addSection() call.

This patch pulls out the increment and adjusts the second use of SecNo accordingly.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D107273

Files:
  llvm/tools/llvm-objcopy/ELF/Object.cpp


Index: llvm/tools/llvm-objcopy/ELF/Object.cpp
===================================================================
--- llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -1342,13 +1342,15 @@
       if (R.HexData.empty())
         continue;
       RecAddr = R.Addr + SegmentAddr + BaseAddr;
-      if (!Section || Section->Addr + Section->Size != RecAddr)
+      if (!Section || (Section->Addr + Section->Size) != RecAddr) {
         // OriginalOffset field is only used to sort section properly, so
         // instead of keeping track of real offset in IHEX file, we use
         // section number.
         Section = &Obj->addSection<OwnedDataSection>(
-            ".sec" + std::to_string(SecNo++), RecAddr,
-            ELF::SHF_ALLOC | ELF::SHF_WRITE, SecNo);
+            ".sec" + std::to_string(SecNo), RecAddr,
+            ELF::SHF_ALLOC | ELF::SHF_WRITE, SecNo + 1);
+        ++SecNo;
+      }
       Section->appendHexData(R.HexData);
       break;
     case IHexRecord::EndOfFile:


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