[PATCH] D25513: [ELF] - Do not crash on duplicate STT_SECTION symbol.

[George Rimar via llvm-commits]

grimar created this revision.
grimar added reviewers: ruiu, rafael, davide.
grimar added subscribers: llvm-commits, grimar, evgeny777.

Global symbols of type STT_SECTION has section filed null, because reference
relocation sections, for which we do not create input sections:

- Type:            STT_SECTION Section:         .rela.text

In case of duplicate symbol lld crashed trying to access nullptr.


https://reviews.llvm.org/D25513

Files:
  ELF/InputFiles.cpp
  ELF/SymbolTable.cpp
  ELF/SymbolTable.h
  test/ELF/invalid/report-duplicates.test


Index: test/ELF/invalid/report-duplicates.test
===================================================================
--- test/ELF/invalid/report-duplicates.test
+++ test/ELF/invalid/report-duplicates.test
@@ -0,0 +1,28 @@
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld %t.o -o %tout 2>&1 | FileCheck %s
+# CHECK: duplicate symbol: in (internal) and {{.*}}.o
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         "00000000"
+  - Name:            .rela.text
+    Type:            SHT_RELA
+    Link:            .symtab
+    AddressAlign:    0x0000000000000008
+    Info:            .text
+    Relocations:
+Symbols:
+  Global:
+    - Type:            STT_SECTION
+      Section:         .rela.text
+    - Type:            STT_SECTION
+      Section:         .rela.text
Index: ELF/SymbolTable.h
===================================================================
--- ELF/SymbolTable.h
+++ ELF/SymbolTable.h
@@ -63,7 +63,7 @@
                        uint8_t Type, bool CanOmitFromDynSym, InputFile *File);
 
   Symbol *addRegular(StringRef Name, const Elf_Sym &Sym,
-                     InputSectionBase<ELFT> *Section);
+                     InputSectionBase<ELFT> *Section, InputFile *File);
   Symbol *addRegular(StringRef Name, uint8_t Binding, uint8_t StOther);
   Symbol *addSynthetic(StringRef N, OutputSectionBase<ELFT> *Section,
                        uintX_t Value, uint8_t StOther);
Index: ELF/SymbolTable.cpp
===================================================================
--- ELF/SymbolTable.cpp
+++ ELF/SymbolTable.cpp
@@ -378,17 +378,17 @@
 
 template <typename ELFT>
 Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, const Elf_Sym &Sym,
-                                      InputSectionBase<ELFT> *Section) {
+                                      InputSectionBase<ELFT> *Section,
+                                      InputFile *File) {
   Symbol *S;
   bool WasInserted;
   std::tie(S, WasInserted) = insert(Name, Sym.getType(), Sym.getVisibility(),
-                                    /*CanOmitFromDynSym*/ false,
-                                    Section ? Section->getFile() : nullptr);
+                                    /*CanOmitFromDynSym*/ false, File);
   int Cmp = compareDefinedNonCommon(S, WasInserted, Sym.getBinding());
   if (Cmp > 0)
     replaceBody<DefinedRegular<ELFT>>(S, Name, Sym, Section);
   else if (Cmp == 0)
-    reportDuplicate(S->body(), Section->getFile());
+    reportDuplicate(S->body(), File);
   return S;
 }
 
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -458,7 +458,7 @@
                                                 /*CanOmitFromDynSym*/ false,
                                                 this)
           ->body();
-    return elf::Symtab<ELFT>::X->addRegular(Name, *Sym, Sec)->body();
+    return elf::Symtab<ELFT>::X->addRegular(Name, *Sym, Sec, this)->body();
   }
 }
 


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