From 272571718c07625206c4d57138c1cd1c1467f203 Mon Sep 17 00:00:00 2001
From: George Rimar <grimar@accesssoftek.com>
Date: Sun, 24 Mar 2019 14:41:45 +0000
Subject: [PATCH] Recommit r356738 "[llvm-objcopy] - Implement
 replaceSectionReferences for GroupSection class."

Fix: r356853 + set AddressAlign to 4 in
Inputs/compress-debug-sections.yaml for the new group section introduced.

Original commit message:

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: 356856
---
 .../ELF/Inputs/compress-debug-sections.yaml   | 20 +++++++
 .../ELF/compress-debug-sections-groups.test   | 53 +++++++++++++++++++
 llvm/tools/llvm-objcopy/ELF/Object.cpp        |  7 +++
 llvm/tools/llvm-objcopy/ELF/Object.h          |  2 +
 4 files changed, 82 insertions(+)
 create mode 100644 llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-groups.test

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 a3c607cc72bc..8da77b36a375 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 +25,24 @@ Sections:
   - Name:            .debug_bar
     Type:            SHT_PROGBITS
     Content:         0000000000000000
+  - Name:            .group
+    Type:            SHT_GROUP
+    Link:            .symtab
+    AddressAlign:    4
+    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 +53,6 @@ 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 000000000000..a72ecbfc04ca
--- /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 39bee8579459..4639d9053943 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 732ff898ed5b..e892d066a6cd 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;
-- 
2.34.1