[PATCH] D59496: [llvm-objcopy] - Fix a st_name of the first symbol table entry.

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 191268.
grimar marked 6 inline comments as done.
grimar added a comment.

- Addressed review comments.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59496/new/

https://reviews.llvm.org/D59496

Files:
  test/tools/llvm-objcopy/ELF/symbol-empty-name.test
  tools/llvm-objcopy/ELF/Object.cpp


Index: tools/llvm-objcopy/ELF/Object.cpp
===================================================================
--- tools/llvm-objcopy/ELF/Object.cpp
+++ tools/llvm-objcopy/ELF/Object.cpp
@@ -297,9 +297,16 @@
   Visitor.visit(*this);
 }
 
-void StringTableSection::addString(StringRef Name) { StrTabBuilder.add(Name); }
+void StringTableSection::addString(StringRef Name) {
+  // Ignore the symbols with empty names, e.g. the null symbol entry,
+  // some section symbols etc.
+  if (!Name.empty())
+    StrTabBuilder.add(Name);
+}
 
 uint32_t StringTableSection::findIndex(StringRef Name) const {
+  if (Name.empty())
+    return 0;
   return StrTabBuilder.getOffset(Name);
 }
 
Index: test/tools/llvm-objcopy/ELF/symbol-empty-name.test
===================================================================
--- /dev/null
+++ test/tools/llvm-objcopy/ELF/symbol-empty-name.test
@@ -0,0 +1,47 @@
+# RUN: yaml2obj %s > %t
+# RUN: llvm-objcopy %t %t2
+# RUN: llvm-readobj -t %t2 | FileCheck %s
+
+## Check that all values of the null symbol are zeroes.
+
+# CHECK:      Symbols [
+# CHECK-NEXT:  Symbol {
+# CHECK-NEXT:    Name:  (0)
+# CHECK-NEXT:    Value: 0x0
+# CHECK-NEXT:    Size: 0
+# CHECK-NEXT:    Binding: Local (0x0)
+# CHECK-NEXT:    Type: None (0x0)
+# CHECK-NEXT:    Other: 0
+# CHECK-NEXT:    Section: Undefined (0x0)
+# CHECK-NEXT:  }
+
+## Check we emit a zero in st_name field when a symbol has no name.
+
+# CHECK:       Name: .text (0)
+# CHECK-NEXT:   Value: 0x0
+# CHECK-NEXT:   Size: 0
+# CHECK-NEXT:   Binding: Local (0x0)
+# CHECK-NEXT:   Type: Section (0x3)
+# CHECK-NEXT:   Other: 0
+# CHECK-NEXT:   Section: .text (0x1)
+# CHECK-NEXT: }
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+Symbols:
+  Local:
+    - Name:     ""
+      Type:     STT_SECTION
+      Section:  .text
+  Global:
+  # We need to have a named symbol, otherwise the original
+  # issue that was fixed is not reproduced by this test.
+    - Name:     foo


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