Use the section name if a STT_SECTION symbol has empty name.

Without this we would have multiple relocations pointing to symbols
with the same name: the empty string. There was no way for yaml2obj to
be able to handle that.

A more general solution would be to unique symbol names in a similar
way to how we unique section names.  In practice I think this covers
all common cases and is a bit more user friendly than using names like
sym1, sym2, sym3, etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312603 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/Object/X86/obj2yaml-dup-symbol-name.s b/test/Object/X86/obj2yaml-dup-symbol-name.s
new file mode 100644 (file)
index 0000000..4cc175a
--- /dev/null
+++ b/test/Object/X86/obj2yaml-dup-symbol-name.s
@@ -0,0 +1,9 @@
+# RUN: llvm-mc %s -o %t.o -filetype=obj -triple=x86_64-pc-linux
+# RUN: obj2yaml %t.o | FileCheck %s
+
+# CHECK: Relocations:
+# CHECK:   Symbol:          .text
+# CHECK: Symbols:
+# CHECK:   - Name:            .text
+
+        .quad .text

diff --git a/test/Object/obj2yaml.test b/test/Object/obj2yaml.test
index 73d466cc4993e7b525ef3e7162b87284ec294e52..3d89f53bafca5db5d088273f5b73a13284facde8 100644 (file)
--- a/test/Object/obj2yaml.test
+++ b/test/Object/obj2yaml.test
@@ -268,19 +268,26 @@ ELF-MIPSEL-NEXT:     - Name:            '$.str'
 ELF-MIPSEL-NEXT:       Type:            STT_OBJECT
 ELF-MIPSEL-NEXT:       Section:         .rodata.str1.1
 ELF-MIPSEL-NEXT:       Size:            0x000000000000000D
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .text
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .text
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .data
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .data
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .bss
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .bss
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .mdebug.abi32
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .mdebug.abi32
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .rodata.str1.1
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .rodata.str1.1
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .reginfo
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .reginfo
-ELF-MIPSEL-NEXT:     - Type:            STT_SECTION
+ELF-MIPSEL-NEXT:     - Name:            .MIPS.abiflags
+ELF-MIPSEL-NEXT:       Type:            STT_SECTION
 ELF-MIPSEL-NEXT:       Section:         .MIPS.abiflags
 ELF-MIPSEL-NEXT:   Global:
 ELF-MIPSEL-NEXT:     - Name:            main
@@ -336,17 +343,22 @@ ELF-MIPS64EL-NEXT:     AddressAlign:    0x0000000000000004
 ELF-MIPS64EL-NEXT:     Content:         ''
 ELF-MIPS64EL-NEXT: Symbols:
 ELF-MIPS64EL-NEXT:   Local:
-ELF-MIPS64EL-NEXT:     - Type:            STT_SECTION
+ELF-MIPS64EL-NEXT:     - Name:            .text
+ELF-MIPS64EL-NEXT:       Type:            STT_SECTION
 ELF-MIPS64EL-NEXT:       Section:         .text
-ELF-MIPS64EL-NEXT:     - Type:            STT_SECTION
+ELF-MIPS64EL-NEXT:     - Name:            .data
+ELF-MIPS64EL-NEXT:       Type:            STT_SECTION
 ELF-MIPS64EL-NEXT:       Section:         .data
-ELF-MIPS64EL-NEXT:     - Type:            STT_SECTION
+ELF-MIPS64EL-NEXT:     - Name:            .bss
+ELF-MIPS64EL-NEXT:       Type:            STT_SECTION
 ELF-MIPS64EL-NEXT:       Section:         .bss
 ELF-MIPS64EL-NEXT:     - Name:            bar
 ELF-MIPS64EL-NEXT:       Section:         .data
-ELF-MIPS64EL-NEXT:     - Type:            STT_SECTION
+ELF-MIPS64EL-NEXT:     - Name:            .MIPS.options
+ELF-MIPS64EL-NEXT:       Type:            STT_SECTION
 ELF-MIPS64EL-NEXT:       Section:         .MIPS.options
-ELF-MIPS64EL-NEXT:     - Type:            STT_SECTION
+ELF-MIPS64EL-NEXT:     - Name:            .pdr
+ELF-MIPS64EL-NEXT:       Type:            STT_SECTION
 ELF-MIPS64EL-NEXT:       Section:         .pdr
 ELF-MIPS64EL-NEXT:   Global:
 ELF-MIPS64EL-NEXT:     - Name:            zed
@@ -382,7 +394,7 @@ ELF-X86-64-NEXT:     AddressAlign:    0x0000000000000008
 ELF-X86-64-NEXT:     Info:            .text
 ELF-X86-64-NEXT:     Relocations:
 ELF-X86-64-NEXT:       - Offset:          0x000000000000000D
-ELF-X86-64-NEXT:         Symbol:          ''
+ELF-X86-64-NEXT:         Symbol:          .rodata.str1.1
 ELF-X86-64-NEXT:         Type:            R_X86_64_32S
 ELF-X86-64-NEXT:       - Offset:          0x0000000000000012
 ELF-X86-64-NEXT:         Symbol:          puts
@@ -396,11 +408,14 @@ ELF-X86-64-NEXT: Symbols:
 ELF-X86-64-NEXT:   Local:
 ELF-X86-64-NEXT:     - Name:            trivial-object-test.s
 ELF-X86-64-NEXT:       Type:            STT_FILE
-ELF-X86-64-NEXT:     - Type:            STT_SECTION
+ELF-X86-64-NEXT:     - Name:            .text
+ELF-X86-64-NEXT:       Type:            STT_SECTION
 ELF-X86-64-NEXT:       Section:         .text
-ELF-X86-64-NEXT:     - Type:            STT_SECTION
+ELF-X86-64-NEXT:     - Name:            .rodata.str1.1
+ELF-X86-64-NEXT:       Type:            STT_SECTION
 ELF-X86-64-NEXT:       Section:         .rodata.str1.1
-ELF-X86-64-NEXT:     - Type:            STT_SECTION
+ELF-X86-64-NEXT:     - Name:            .note.GNU-stack
+ELF-X86-64-NEXT:       Type:            STT_SECTION
 ELF-X86-64-NEXT:       Section:         .note.GNU-stack
 ELF-X86-64-NEXT:   Global:
 ELF-X86-64-NEXT:     - Name:            main
@@ -431,9 +446,11 @@ ELF-AVR-NEXT:     AddressAlign:    0x0000000000000001
 ELF-AVR-NEXT:     Content:         ''
 ELF-AVR-NEXT: Symbols:
 ELF-AVR-NEXT:   Local:
-ELF-AVR-NEXT:     - Type:            STT_SECTION
+ELF-AVR-NEXT:     - Name:           .text
+ELF-AVR-NEXT:       Type:            STT_SECTION
 ELF-AVR-NEXT:       Section:         .text
-ELF-AVR-NEXT:     - Type:            STT_SECTION
+ELF-AVR-NEXT:     - Name:           .data
+ELF-AVR-NEXT:       Type:            STT_SECTION
 ELF-AVR-NEXT:       Section:         .data
 ELF-AVR-NEXT:       Value:           0x0000000000800060
 ELF-AVR-NEXT:     - Name:            a.o

diff --git a/tools/obj2yaml/elf2yaml.cpp b/tools/obj2yaml/elf2yaml.cpp
index b603cb84aea6a4b6ce06bef4408583dc650773cc..8997a5c4211b368afb3afc8d458c64e975c5e842 100644 (file)
--- a/tools/obj2yaml/elf2yaml.cpp
+++ b/tools/obj2yaml/elf2yaml.cpp
@@ -36,6 +36,8 @@ class ELFDumper {
   DenseSet<StringRef> UsedSectionNames;
   std::vector<std::string> SectionNames;
   Expected<StringRef> getUniquedSectionName(const Elf_Shdr *Sec);
+  Expected<StringRef> getSymbolName(const Elf_Sym *Sym, StringRef StrTable,
+                                    const Elf_Shdr *SymTab);
 
   const object::ELFFile<ELFT> &Obj;
   ArrayRef<Elf_Word> ShndxTable;
@@ -87,6 +89,23 @@ ELFDumper<ELFT>::getUniquedSectionName(const Elf_Shdr *Sec) {
   return Ret;
 }
 
+template <class ELFT>
+Expected<StringRef> ELFDumper<ELFT>::getSymbolName(const Elf_Sym *Sym,
+                                                   StringRef StrTable,
+                                                   const Elf_Shdr *SymTab) {
+  Expected<StringRef> SymbolNameOrErr = Sym->getName(StrTable);
+  if (!SymbolNameOrErr)
+    return SymbolNameOrErr;
+  StringRef Name = *SymbolNameOrErr;
+  if (Name.empty() && Sym->getType() == ELF::STT_SECTION) {
+    auto ShdrOrErr = Obj.getSection(Sym, SymTab, ShndxTable);
+    if (!ShdrOrErr)
+      return ShdrOrErr.takeError();
+    return getUniquedSectionName(*ShdrOrErr);
+  }
+  return Name;
+}
+
 template <class ELFT> ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
   auto Y = make_unique<ELFYAML::Object>();
 
@@ -217,7 +236,7 @@ ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
   S.Size = Sym->st_size;
   S.Other = Sym->st_other;
 
-  Expected<StringRef> SymbolNameOrErr = Sym->getName(StrTable);
+  Expected<StringRef> SymbolNameOrErr = getSymbolName(Sym, StrTable, SymTab);
   if (!SymbolNameOrErr)
     return errorToErrorCode(SymbolNameOrErr.takeError());
   S.Name = SymbolNameOrErr.get();
@@ -259,7 +278,7 @@ std::error_code ELFDumper<ELFT>::dumpRelocation(const RelT *Rel,
   StringRef StrTab = *StrTabOrErr;
 
   if (Sym) {
-    Expected<StringRef> NameOrErr = Sym->getName(StrTab);
+    Expected<StringRef> NameOrErr = getSymbolName(Sym, StrTab, SymTab);
     if (!NameOrErr)
       return errorToErrorCode(NameOrErr.takeError());
     R.Symbol = NameOrErr.get();
@@ -425,7 +444,7 @@ ErrorOr<ELFYAML::Group *> ELFDumper<ELFT>::dumpGroup(const Elf_Shdr *Shdr) {
   auto sectionContents = Obj.getSectionContents(Shdr);
   if (!sectionContents)
     return errorToErrorCode(sectionContents.takeError());
-  Expected<StringRef> symbolName = symbol->getName(StrTab);
+  Expected<StringRef> symbolName = getSymbolName(symbol, StrTab, Symtab);
   if (!symbolName)
     return errorToErrorCode(symbolName.takeError());
   S->Info = *symbolName;