[PATCH] D23201: [ELF] - Fix for: error "invalid section index: xxx" when linking FreeBSD kernel.

[George Rimar via llvm-commits]

grimar updated this revision to Diff 67487.
grimar added a comment.

- Addressed review comments.


https://reviews.llvm.org/D23201

Files:
  ELF/InputFiles.cpp
  ELF/Writer.cpp
  test/ELF/section-symbols.test

Index: test/ELF/section-symbols.test
===================================================================
--- test/ELF/section-symbols.test
+++ test/ELF/section-symbols.test
@@ -0,0 +1,35 @@
+# RUN: yaml2obj %s -o %t
+# RUN: ld.lld -shared %t -o %tout
+
+# Verify that lld can handle STT_SECTION symbols associated
+# with SHT_REL[A]/SHT_SYMTAB/SHT_STRTAB sections.
+
+!ELF
+FileHeader:      
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  OSABI:           ELFOSABI_FREEBSD
+  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:
+  Local:
+    - Type:            STT_SECTION
+      Section:         .rela.text
+    - Type:            STT_SECTION
+      Section:         .shstrtab
+    - Type:            STT_SECTION
+      Section:         .symtab
+    - Type:            STT_SECTION
+      Section:         .strtab
Index: ELF/Writer.cpp
===================================================================
--- ELF/Writer.cpp
+++ ELF/Writer.cpp
@@ -97,7 +97,8 @@
 }
 
 template <class ELFT> void elf::reportDiscarded(InputSectionBase<ELFT> *IS) {
-  if (!Config->PrintGcSections || !IS || IS->Live)
+  if (!Config->PrintGcSections || !IS || IS->Live ||
+      IS == &InputSection<ELFT>::Discarded)
     return;
   errs() << "removing unused section from '" << IS->getSectionName()
          << "' in file '" << IS->getFile()->getName() << "'\n";
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -270,6 +270,16 @@
     default:
       Sections[I] = createInputSection(Sec);
     }
+
+    // We found that GNU assembler 2.17.50 [FreeBSD] 2007-07-03
+    // could generate broken objects. STT_SECTION symbols can be
+    // associated with SHT_REL[A]/SHT_SYMTAB/SHT_STRTAB sections.
+    // In this case we mark these sections as discarded to handle
+    // situation properly.
+    if (Sec.sh_type == SHT_SYMTAB || Sec.sh_type == SHT_STRTAB ||
+        Sec.sh_type == SHT_RELA || Sec.sh_type == SHT_RELA)
+      if (!Sections[I])
+        Sections[I] = &InputSection<ELFT>::Discarded;
   }
 }
 


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