[llvm-objcopy] - Implement replaceSectionReferences for GroupSection class.

Currently, llvm-objcopy incorrectly handles compression and decompression of the
sections from COMDAT groups, because we do not implement the
replaceSectionReferences for this type of the sections.

The patch does that.

Differential revision: https://reviews.llvm.org/D59638

llvm-svn: 356738

4 files changed, 81 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml b/llvm/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
index a3c607cc72b..15fb7fdf58c 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
+++ b/llvm/test/tools/llvm-objcopy/ELF/Inputs/compress-debug-sections.yaml
@@ -25,6 +25,23 @@ Sections:
   - Name:            .debug_bar
     Type:            SHT_PROGBITS
     Content:         0000000000000000
+  - Name:            .group
+    Type:            SHT_GROUP
+    Link:            .symtab
+    EntSize:         0x0000000000000004
+    Info:            groupname
+    Members:         
+      - SectionOrType:   GRP_COMDAT
+      - SectionOrType:   .text.in.group
+      - SectionOrType:   .debug_in_group
+  - Name:            .text.in.group
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+    Content:         '00'
+  - Name:            .debug_in_group
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_GROUP ]
+    Content:         '00'
 Symbols:
   Global:
     - Name:    .debug_foo
@@ -35,4 +52,6 @@ Symbols:
       Section: .notdebug_foo
     - Name:    .Linfo_string0
       Section: .debug_bar
+    - Name:    groupname
+      Section: .group
 ...
diff --git a/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-groups.test b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-groups.test
new file mode 100644
index 00000000000..a72ecbfc04c
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-groups.test
@@ -0,0 +1,53 @@
+# REQUIRES: zlib
+
+## In this test, we check how llvm-objcopy handles compression/decompression
+## of debug sections included in a COMDAT group.
+
+# RUN: yaml2obj %p/Inputs/compress-debug-sections.yaml -o %t.o
+
+## Check compression of debug sections.
+# RUN: llvm-objcopy --compress-debug-sections %t.o %t-compressed.o
+# RUN: llvm-readobj -s -elf-section-groups %t-compressed.o | \
+# RUN:   FileCheck %s --check-prefixes=CHECK,COMPRESS
+
+## Check zlib-gnu compression of debug sections.
+# RUN: llvm-objcopy --compress-debug-sections=zlib-gnu %t.o %t-compressed-gnu.o
+# RUN: llvm-readobj -s -elf-section-groups %t-compressed-gnu.o | \
+# RUN:   FileCheck %s --check-prefixes=CHECK,COMPRESSZLIB
+
+## Check decompression of debug sections.
+# RUN: llvm-objcopy --decompress-debug-sections %t-compressed.o %t-decompressed.o
+# RUN: llvm-readobj -elf-section-groups %t-decompressed.o | \
+# RUN:   FileCheck %s --check-prefixes=CHECK,DECOMPRESS
+
+## Check decompression of zlib-gnu debug sections.
+# RUN: llvm-objcopy --decompress-debug-sections %t-compressed-gnu.o %t-decompressed-gnu.o
+# RUN: llvm-readobj -elf-section-groups %t-decompressed-gnu.o | \
+# RUN:   FileCheck %s --check-prefixes=CHECK,DECOMPRESS
+
+# COMPRESSZLIB:      Name: .zdebug_in_group
+# COMPRESSZLIB-NEXT: Type: SHT_PROGBITS
+# COMPRESSZLIB-NEXT: Flags [
+# COMPRESSZLIB-NEXT:   SHF_GROUP
+# COMPRESSZLIB-NEXT: ]
+
+# COMPRESS:      Name: .debug_in_group
+# COMPRESS-NEXT: Type: SHT_PROGBITS
+# COMPRESS-NEXT: Flags [
+# COMPRESS-NEXT:   SHF_COMPRESSED
+# COMPRESS-NEXT:   SHF_GROUP
+# COMPRESS-NEXT: ]
+
+# CHECK:           Group {
+# CHECK-NEXT:        Name: .group
+# CHECK-NEXT:        Index:
+# CHECK-NEXT:        Link:
+# CHECK-NEXT:        Info:
+# CHECK-NEXT:        Type: COMDAT
+# CHECK-NEXT:        Signature: groupname
+# CHECK-NEXT:        Section(s) in group [
+# CHECK-NEXT:          .text.in.group
+# COMPRESSZLIB-NEXT:   .zdebug_in_group
+# COMPRESS-NEXT:       .debug_in_group
+# DECOMPRESS-NEXT:     .debug_in_group
+# CHECK-NEXT:        ]
diff --git a/llvm/tools/llvm-objcopy/ELF/Object.cpp b/llvm/tools/llvm-objcopy/ELF/Object.cpp
index ccc6efa5dbd..38cf3ad50a5 100644
--- a/llvm/tools/llvm-objcopy/ELF/Object.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/Object.cpp
@@ -689,6 +689,13 @@ void GroupSection::markSymbols() {
     Sym->Referenced = true;
 }
 
+void GroupSection::replaceSectionReferences(
+    const DenseMap<SectionBase *, SectionBase *> &FromTo) {
+  for (SectionBase *&Sec : GroupMembers)
+    if (SectionBase *To = FromTo.lookup(Sec))
+      Sec = To;
+}
+
 void Section::initialize(SectionTableRef SecTable) {
   if (Link != ELF::SHN_UNDEF) {
     LinkSection =
diff --git a/llvm/tools/llvm-objcopy/ELF/Object.h b/llvm/tools/llvm-objcopy/ELF/Object.h
index 732ff898ed5..e892d066a6c 100644
--- a/llvm/tools/llvm-objcopy/ELF/Object.h
+++ b/llvm/tools/llvm-objcopy/ELF/Object.h
@@ -633,6 +633,8 @@ public:
   void finalize() override;
   Error removeSymbols(function_ref<bool(const Symbol &)> ToRemove) override;
   void markSymbols() override;
+  void replaceSectionReferences(
+      const DenseMap<SectionBase *, SectionBase *> &FromTo) override;
 
   static bool classof(const SectionBase *S) {
     return S->Type == ELF::SHT_GROUP;