[PATCH] D139210: [llvm-objcopy] Fix --section-add when section contain empty bytes

[Guilhem Morer via Phabricator via llvm-commits]

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Implicit cast between char* and StringRef when writing sections.

Reproduce:

  $> llvm-objcopy --dump-section=name=name.data out.wasm
  $> llvm-objcopy --remove-section=name out.wasm out_no_name.wasm
  $> llvm-objcopy --add-section=name=name.data out_no_name.wasm out_new_name.wasm
  
  # With wasm-objdump -h we can see that the name section is not totally copied in the new wasm file (if it actually contain empty bytes)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139210

Files:
  llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp


Index: llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp
===================================================================
--- llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp
+++ llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp
@@ -126,9 +126,11 @@
     Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
     Sec.Name = NewSection.SectionName;
 
+    llvm::StringRef InputData =
+        llvm::StringRef(NewSection.SectionData->getBufferStart(),
+                        NewSection.SectionData->getBufferSize());
     std::unique_ptr<MemoryBuffer> BufferCopy = MemoryBuffer::getMemBufferCopy(
-        NewSection.SectionData->getBufferStart(),
-        NewSection.SectionData->getBufferIdentifier());
+        InputData, NewSection.SectionData->getBufferIdentifier());
     Sec.Contents = makeArrayRef<uint8_t>(
         reinterpret_cast<const uint8_t *>(BufferCopy->getBufferStart()),
         BufferCopy->getBufferSize());


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