Change ELF tools to allow multiple sections per file.

This is how multi-partition combined output files are going to look. If we
see multiple sections, the tools will just read the first one.

Differential Revision: https://reviews.llvm.org/D62349

llvm-svn: 361869

include/llvm/Object/ELFObjectFile.h

@@ -951,15 +951,13 @@ ELFObjectFile<ELFT>::create(MemoryBufferRef Object) {
   for (const Elf_Shdr &Sec : *SectionsOrErr) {
     switch (Sec.sh_type) {
     case ELF::SHT_DYNSYM: {
-      if (DotDynSymSec)
-        return createError("More than one dynamic symbol table!");
-      DotDynSymSec = &Sec;
+      if (!DotDynSymSec)
+        DotDynSymSec = &Sec;
       break;
     }
     case ELF::SHT_SYMTAB: {
-      if (DotSymtabSec)
-        return createError("More than one static symbol table!");
-      DotSymtabSec = &Sec;
+      if (!DotSymtabSec)
+        DotSymtabSec = &Sec;
       break;
     }
     case ELF::SHT_SYMTAB_SHNDX: {

test/Object/multiple-sections.yaml

@@ -0,0 +1,62 @@
+# RUN: yaml2obj %s -o %t.o
+# RUN: llvm-readobj -a --elf-cg-profile --addrsig %t.o | FileCheck %s
+
+# Test that multiple sections with the same type does not trigger an error.
+
+# CHECK: ElfHeader {
+# CHECK: SHT_GNU_verdef {
+# CHECK: SHT_GNU_verneed {
+# CHECK: CGProfile [
+# CHECK: Addrsig [
+
+--- !ELF
+FileHeader:      
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:        
+  - Name:            .symtab2
+    Type:            SHT_SYMTAB
+    Link:            .strtab
+    Content:         ''
+    EntSize:         24
+  - Name:            .versym
+    Type:            SHT_GNU_versym
+    Entries:         [ ]
+  - Name:            .versym2
+    Type:            SHT_GNU_versym
+    Entries:         [ ]
+  - Name:            .verdef
+    Type:            SHT_GNU_verdef
+    Info:            0x0000000000000000
+    Entries:
+  - Name:            .verdef2
+    Type:            SHT_GNU_verdef
+    Info:            0x0000000000000000
+    Entries:
+  - Name:            .verneed
+    Type:            SHT_GNU_verneed
+    Info:            0x0000000000000000
+    Dependencies:
+  - Name:            .verneed2
+    Type:            SHT_GNU_verneed
+    Info:            0x0000000000000000
+    Dependencies:
+  - Name:            .llvm.call-graph-profile
+    Type:            SHT_LLVM_CALL_GRAPH_PROFILE
+    Content:         ''
+    EntSize:         16
+  - Name:            .llvm.call-graph-profile2
+    Type:            SHT_LLVM_CALL_GRAPH_PROFILE
+    Content:         ''
+    EntSize:         16
+  - Name:            .llvm_addrsig
+    Type:            SHT_LLVM_ADDRSIG
+    Content:         ''
+  - Name:            .llvm_addrsig2
+    Type:            SHT_LLVM_ADDRSIG
+    Content:         ''
+Symbols:         
+  - Name:            f
+...

tools/llvm-readobj/ELFDumper.cpp

@@ -1414,45 +1414,40 @@ ELFDumper<ELFT>::ELFDumper(const object::ELFObjectFile<ELFT> *ObjF,
   for (const Elf_Shdr &Sec : unwrapOrError(Obj->sections())) {
     switch (Sec.sh_type) {
     case ELF::SHT_SYMTAB:
-      if (DotSymtabSec != nullptr)
-        reportError("Multiple SHT_SYMTAB");
-      DotSymtabSec = &Sec;
+      if (!DotSymtabSec)
+        DotSymtabSec = &Sec;
       break;
     case ELF::SHT_DYNSYM:
-      if (DynSymRegion.Size)
-        reportError("Multiple SHT_DYNSYM");
-      DynSymRegion = createDRIFrom(&Sec);
-      // This is only used (if Elf_Shdr present)for naming section in GNU style
-      DynSymtabName = unwrapOrError(Obj->getSectionName(&Sec));
-      DynamicStringTable = unwrapOrError(Obj->getStringTableForSymtab(Sec));
+      if (!DynSymRegion.Size) {
+        DynSymRegion = createDRIFrom(&Sec);
+        // This is only used (if Elf_Shdr present)for naming section in GNU
+        // style
+        DynSymtabName = unwrapOrError(Obj->getSectionName(&Sec));
+        DynamicStringTable = unwrapOrError(Obj->getStringTableForSymtab(Sec));
+      }
       break;
     case ELF::SHT_SYMTAB_SHNDX:
       ShndxTable = unwrapOrError(Obj->getSHNDXTable(Sec));
       break;
     case ELF::SHT_GNU_versym:
-      if (SymbolVersionSection != nullptr)
-        reportError("Multiple SHT_GNU_versym");
-      SymbolVersionSection = &Sec;
+      if (!SymbolVersionSection)
+        SymbolVersionSection = &Sec;
       break;
     case ELF::SHT_GNU_verdef:
-      if (SymbolVersionDefSection != nullptr)
-        reportError("Multiple SHT_GNU_verdef");
-      SymbolVersionDefSection = &Sec;
+      if (!SymbolVersionDefSection)
+        SymbolVersionDefSection = &Sec;
       break;
     case ELF::SHT_GNU_verneed:
-      if (SymbolVersionNeedSection != nullptr)
-        reportError("Multiple SHT_GNU_verneed");
-      SymbolVersionNeedSection = &Sec;
+      if (!SymbolVersionNeedSection)
+        SymbolVersionNeedSection = &Sec;
       break;
     case ELF::SHT_LLVM_CALL_GRAPH_PROFILE:
-      if (DotCGProfileSec != nullptr)
-        reportError("Multiple .llvm.call-graph-profile");
-      DotCGProfileSec = &Sec;
+      if (!DotCGProfileSec)
+        DotCGProfileSec = &Sec;
       break;
     case ELF::SHT_LLVM_ADDRSIG:
-      if (DotAddrsigSec != nullptr)
-        reportError("Multiple .llvm_addrsig");
-      DotAddrsigSec = &Sec;
+      if (!DotAddrsigSec)
+        DotAddrsigSec = &Sec;
       break;
     }
   }