[PATCH] D55235: llvm-objcopy: Improve/simplify llvm::Error handling during notes iteration

[David Blaikie via Phabricator via llvm-commits]

dblaikie updated this revision to Diff 176490.
dblaikie added a comment.

Strengthen require error checking from the iterator


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55235/new/

https://reviews.llvm.org/D55235

Files:
  include/llvm/Object/ELFTypes.h
  tools/llvm-objcopy/ELF/ELFObjcopy.cpp


Index: tools/llvm-objcopy/ELF/ELFObjcopy.cpp
===================================================================
--- tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -123,14 +123,9 @@
     if (Phdr.p_type != PT_NOTE)
       continue;
     Error Err = Error::success();
-    if (Err)
-      llvm_unreachable("Error::success() was an error.");
-    for (const auto &Note : In.notes(Phdr, Err)) {
-      if (Err)
-        return std::move(Err);
+    for (const auto &Note : In.notes(Phdr, Err))
       if (Note.getType() == NT_GNU_BUILD_ID && Note.getName() == ELF_NOTE_GNU)
         return Note.getDesc();
-    }
     if (Err)
       return std::move(Err);
   }
Index: include/llvm/Object/ELFTypes.h
===================================================================
--- include/llvm/Object/ELFTypes.h
+++ include/llvm/Object/ELFTypes.h
@@ -631,6 +631,7 @@
   // Stop iteration and indicate an overflow.
   void stopWithOverflowError() {
     Nhdr = nullptr;
+    ErrorAsOutParameter EAOP(Err);
     *Err = make_error<StringError>("ELF note overflows container",
                                    object_error::parse_failed);
   }
@@ -642,9 +643,12 @@
   // container, either cleanly or with an overflow error.
   void advanceNhdr(const uint8_t *NhdrPos, size_t NoteSize) {
     RemainingSize -= NoteSize;
-    if (RemainingSize == 0u)
+    if (RemainingSize == 0u) {
+      // Ensure that if the iterator walks to the end, the error is checked
+      // afterwards.
+      *Err = Error::success();
       Nhdr = nullptr;
-    else if (sizeof(*Nhdr) > RemainingSize)
+    } else if (sizeof(*Nhdr) > RemainingSize)
       stopWithOverflowError();
     else {
       Nhdr = reinterpret_cast<const Elf_Nhdr_Impl<ELFT> *>(NhdrPos + NoteSize);
@@ -657,6 +661,7 @@
   explicit Elf_Note_Iterator_Impl(Error &Err) : Err(&Err) {}
   Elf_Note_Iterator_Impl(const uint8_t *Start, size_t Size, Error &Err)
       : RemainingSize(Size), Err(&Err) {
+    consumeError(std::move(Err));
     assert(Start && "ELF note iterator starting at NULL");
     advanceNhdr(Start, 0u);
   }


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