[Lldb-commits] [lldb] r327123 - [elf] Remove one copy of the section merging code

[Pavel Labath via lldb-commits]

Author: labath
Date: Fri Mar  9 04:30:09 2018
New Revision: 327123

URL: http://llvm.org/viewvc/llvm-project?rev=327123&view=rev
Log:
[elf] Remove one copy of the section merging code

Summary:
Besides being superfluous, this double merging was actually wrong and
causing some sections to be added twice. The reason for that was that
the code assumes section IDs are unique in the section list, but this is
only true if all sections in the list come from the same object file.

Reviewers: fjricci, jankratochvil

Subscribers: emaste, lldb-commits, arichardson

Differential Revision: https://reviews.llvm.org/D44157

Added:
    lldb/trunk/lit/Modules/elf-duplicate-section.yaml
Modified:
    lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

Added: lldb/trunk/lit/Modules/elf-duplicate-section.yaml
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/Modules/elf-duplicate-section.yaml?rev=327123&view=auto
==============================================================================
--- lldb/trunk/lit/Modules/elf-duplicate-section.yaml (added)
+++ lldb/trunk/lit/Modules/elf-duplicate-section.yaml Fri Mar  9 04:30:09 2018
@@ -0,0 +1,42 @@
+# RUN: mkdir -p %t/.build-id/1b
+# RUN: yaml2obj %s > %t/.build-id/1b/8a73ac238390e32a7ff4ac8ebe4d6a41ecf5c9.debug
+# RUN: cd %t
+# RUN: llvm-objcopy --strip-all --add-gnu-debuglink=.build-id/1b/8a73ac238390e32a7ff4ac8ebe4d6a41ecf5c9.debug %t/.build-id/1b/8a73ac238390e32a7ff4ac8ebe4d6a41ecf5c9.debug %t/stripped.out
+# RUN: lldb-test module-sections %t/stripped.out | FileCheck %s
+
+# Make sure that the debug_frame section is present only once.
+# CHECK: Name: .debug_frame
+# CHECK-NOT: .debug_frame
+
+--- !ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+  Entry:           0x00000000004003D0
+Sections:
+  - Name:            .note.gnu.build-id
+    Type:            SHT_NOTE
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x0000000000400274
+    AddressAlign:    0x0000000000000004
+    Content:         040000001400000003000000474E55001B8A73AC238390E32A7FF4AC8EBE4D6A41ECF5C9
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x00000000004003D0
+    AddressAlign:    0x0000000000000010
+    Content:         DEADBEEFBAADF00D
+  - Name:            .debug_frame
+    Type:            SHT_PROGBITS
+    AddressAlign:    0x0000000000000008
+    Content:         DEADBEEFBAADF00D
+Symbols:
+  Local:
+    - Name:            main
+      Type:            STT_FUNC
+      Section:         .text
+      Value:           0x00000000004003D0
+      Size:            0x0000000000000008
+...

Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp?rev=327123&r1=327122&r2=327123&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp Fri Mar  9 04:30:09 2018
@@ -1986,38 +1986,10 @@ void ObjectFileELF::CreateSections(Secti
     }
   }
 
-  if (m_sections_ap.get()) {
-    if (GetType() == eTypeDebugInfo) {
-      static const SectionType g_sections[] = {
-          eSectionTypeDWARFDebugAbbrev,   eSectionTypeDWARFDebugAddr,
-          eSectionTypeDWARFDebugAranges,  eSectionTypeDWARFDebugCuIndex,
-          eSectionTypeDWARFDebugFrame,    eSectionTypeDWARFDebugInfo,
-          eSectionTypeDWARFDebugLine,     eSectionTypeDWARFDebugLoc,
-          eSectionTypeDWARFDebugMacInfo,  eSectionTypeDWARFDebugPubNames,
-          eSectionTypeDWARFDebugPubTypes, eSectionTypeDWARFDebugRanges,
-          eSectionTypeDWARFDebugStr,      eSectionTypeDWARFDebugStrOffsets,
-          eSectionTypeELFSymbolTable,
-      };
-      SectionList *elf_section_list = m_sections_ap.get();
-      for (size_t idx = 0; idx < sizeof(g_sections) / sizeof(g_sections[0]);
-           ++idx) {
-        SectionType section_type = g_sections[idx];
-        SectionSP section_sp(
-            elf_section_list->FindSectionByType(section_type, true));
-        if (section_sp) {
-          SectionSP module_section_sp(
-              unified_section_list.FindSectionByType(section_type, true));
-          if (module_section_sp)
-            unified_section_list.ReplaceSection(module_section_sp->GetID(),
-                                                section_sp);
-          else
-            unified_section_list.AddSection(section_sp);
-        }
-      }
-    } else {
-      unified_section_list = *m_sections_ap;
-    }
-  }
+  // For eTypeDebugInfo files, the Symbol Vendor will take care of updating the
+  // unified section list.
+  if (GetType() != eTypeDebugInfo)
+    unified_section_list = *m_sections_ap;
 }
 
 // Find the arm/aarch64 mapping symbol character in the given symbol name.