[PATCH] D143508: [ELF][llvm-objcopy] Reject duplicate SHT_SYMTAB sections.

[Moshe via Phabricator via llvm-commits]

MosheBerman created this revision.
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This commit addresses [issue #60448][1].

- Add a check for duplicate `SHT_SYMTAB` sections.
- Add a test that verifies that the error is logged as expected.

Code Style
----------

I looked at the relevant parts of the [LLVM Coding Standards][2] for guidance on formatting the logic checking, but didn't see anything explicit.

  1. Error message
- I included the quote from the ELF gABI docs in the error message to make it more searchable online.
  - If we can add a suggestion for how a user can proceed that would be great, imo.

[1]: https://github.com/llvm/llvm-project/issues/60448
[2]: https://llvm.org/docs/CodingStandards.html#assert-liberally


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D143508

Files:
  llvm/lib/ObjCopy/ELF/ELFObject.cpp
  llvm/test/tools/llvm-objcopy/ELF/symtab-duplicate.test


Index: llvm/test/tools/llvm-objcopy/ELF/symtab-duplicate.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-objcopy/ELF/symtab-duplicate.test
@@ -0,0 +1,18 @@
+# RUN: yaml2obj %s -o %t
+# RUN: not llvm-objcopy -O binary %t - 2>&1 | FileCheck %s --check-prefix=SYMTAB
+# SYMTAB: found multiple SHT_SYMTAB sections; Currently, an object file may have only one
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .symtab
+    Type: SHT_SYMTAB
+    Flags: [ SHF_ALLOC ]
+  - Name: .symtab2
+    Type: SHT_SYMTAB
+    Flags: [ SHF_ALLOC ]
+    
\ No newline at end of file
Index: llvm/lib/ObjCopy/ELF/ELFObject.cpp
===================================================================
--- llvm/lib/ObjCopy/ELF/ELFObject.cpp
+++ llvm/lib/ObjCopy/ELF/ELFObject.cpp
@@ -1704,6 +1704,11 @@
     else
       return Data.takeError();
   case SHT_SYMTAB: {
+    // Duplicate SHT_SYMTAB sections are forbidden by the ELF gABI.
+    if (Obj.SymbolTable != nullptr)
+      return createStringError(llvm::errc::invalid_argument,
+                               "found multiple SHT_SYMTAB sections. "
+                               "Currently, an object file may have only one");
     auto &SymTab = Obj.addSection<SymbolTableSection>();
     Obj.SymbolTable = &SymTab;
     return SymTab;


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