[PATCH] D158004: llvm-nm ignore the Import symbol file for the --export-symbol option.

[Digger Lin via Phabricator via llvm-commits]

DiggerLin created this revision.
DiggerLin added reviewers: stephenpeckham, hubert.reinterpretcast, jhenderson.
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in the https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/ToolChains/AIX.cpp#L236, 
clang use  llvm-nm to export symbol, but the input of the clang command line maybe include the imported symbol files(the first line of file begin with #!) which do not need to be exported by `llvm-nm --export-symbols'.

`llvm-nm --export-symbols`  reports "a invalid object file" error on the the Imported symbol files currently. When Clang driver invoke the `llvm-nm --export-symbols`  on imported symbol file, it will cause the clang has linker error on AIX OS.

in the patch, the  llvm-nm ignore the Import symbol file for the --export-symbol option. it will fix above defect.

in t


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D158004

Files:
  llvm/test/tools/llvm-nm/XCOFF/export-symbols.test
  llvm/tools/llvm-nm/llvm-nm.cpp


Index: llvm/tools/llvm-nm/llvm-nm.cpp
===================================================================
--- llvm/tools/llvm-nm/llvm-nm.cpp
+++ llvm/tools/llvm-nm/llvm-nm.cpp
@@ -2262,6 +2262,14 @@
   if (error(BufferOrErr.getError(), Filename))
     return SymbolList;
 
+  // Ignore parsing an imported symbol file that begins with #! when we export
+  // symbols.
+  const char *BuffStart = (*BufferOrErr)->getBufferStart();
+  size_t BufferSize = (*BufferOrErr)->getBufferSize();
+  if (ExportSymbols && BufferSize >= 2 && BuffStart[0] == '#' &&
+      BuffStart[1] == '!')
+    return SymbolList;
+
   LLVMContext Context;
   LLVMContext *ContextPtr = NoLLVMBitcode ? nullptr : &Context;
   Expected<std::unique_ptr<Binary>> BinaryOrErr =
Index: llvm/test/tools/llvm-nm/XCOFF/export-symbols.test
===================================================================
--- llvm/test/tools/llvm-nm/XCOFF/export-symbols.test
+++ llvm/test/tools/llvm-nm/XCOFF/export-symbols.test
@@ -52,6 +52,10 @@
 # RUN: yaml2obj -DFLAG=0x2000 --docnum=2 %s -o %t_shared.o
 # RUN: llvm-nm --export-symbols %t_shared.o | count 0
 
+## Test ignoring the parsing an imported symbol file that  begins with #!
+# RUN: echo "#!" > imp.txt
+# RUN: llvm-nm --export-symbols imp.txt 2>&1 | FileCheck --allow-empty --implicit-check-not={{.}} %s
+
 --- !XCOFF
 FileHeader:
   MagicNumber:       0x1DF


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