[llvm-objcopy] Fix SHT_GROUP ordering.
Summary:
When llvm-objcopy sorts sections during finalization, it only sorts based on the offset, which can cause the group section to come after the sections it contains. This causes link failures when using gold to link objects created by llvm-objcopy.
Fix this for now by copying GNU objcopy's behavior of placing SHT_GROUP sections first. In the future, we may want to remove this sorting entirely to more closely preserve the input file layout.
This fixes https://bugs.llvm.org/show_bug.cgi?id=42052.
Reviewers: jakehehrlich, jhenderson, MaskRay, espindola, alexshap
Reviewed By: MaskRay
Subscribers: phuongtrang148993, emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62620
llvm-svn: 362973
diff --git a/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
index 2abd22e..d2811b9 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib-gnu.test
@@ -14,8 +14,7 @@
# CHECK: .debug_foo:
# CHECK-NEXT: 0000 00000000 00000000
-# CHECK-HEADER: Index: 1
-# CHECK-HEADER-NEXT: Name: .debug_foo
+# CHECK-HEADER: Name: .debug_foo
# CHECK-HEADER-NEXT: Type: SHT_PROGBITS
# CHECK-HEADER-NEXT: Flags [
# CHECK-HEADER-NEXT: ]
@@ -27,9 +26,8 @@
# CHECK-COMPRESSED: ZLIB
# CHECK-COMPRESSED: .notdebug_foo:
-# CHECK-FLAGS-NOT: Name: .debug_foo
-# CHECK-FLAGS: Index: 1
-# CHECK-FLAGS-NEXT: Name: .zdebug_foo
+# CHECK-FLAGS-NOT: Name: .debug_foo
+# CHECK-FLAGS: Name: .zdebug_foo
# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
# CHECK-FLAGS-NEXT: Flags [
# CHECK-FLAGS-NEXT: ]
@@ -49,11 +47,6 @@
# CHECK-FLAGS-NEXT: Type: SHT_RELA
# CHECK-FLAGS-NEXT: Flags [
# CHECK-FLAGS-NEXT: ]
-# CHECK-FLAGS-NEXT: Address:
-# CHECK-FLAGS-NEXT: Offset:
-# CHECK-FLAGS-NEXT: Size:
-# CHECK-FLAGS-NEXT: Link:
-# CHECK-FLAGS-NEXT: Info: 1
# CHECK-FLAGS: Relocations [
# CHECK-FLAGS-NEXT: .rela.debug_foo {
diff --git a/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
index 374a826..481071a 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/compress-debug-sections-zlib.test
@@ -14,8 +14,7 @@
# CHECK: .debug_foo:
# CHECK-NEXT: 0000 00000000 00000000
-# CHECK-HEADER: Index: 1
-# CHECK-HEADER-NEXT: Name: .debug_foo
+# CHECK-HEADER: Name: .debug_foo
# CHECK-HEADER-NEXT: Type: SHT_PROGBITS
# CHECK-HEADER-NEXT: Flags [
# CHECK-HEADER-NEXT: ]
@@ -26,8 +25,7 @@
# CHECK-COMPRESSED: .debug_foo:
# CHECK-COMPRESSED: .notdebug_foo:
-# CHECK-FLAGS: Index: 1
-# CHECK-FLAGS-NEXT: Name: .debug_foo
+# CHECK-FLAGS: Name: .debug_foo
# CHECK-FLAGS-NEXT: Type: SHT_PROGBITS
# CHECK-FLAGS-NEXT: Flags [
# CHECK-FLAGS-NEXT: SHF_COMPRESSED
@@ -53,7 +51,6 @@
# CHECK-FLAGS-NEXT: Offset:
# CHECK-FLAGS-NEXT: Size:
# CHECK-FLAGS-NEXT: Link:
-# CHECK-FLAGS-NEXT: Info: 1
# CHECK-FLAGS: Relocations [
# CHECK-FLAGS-NEXT: .rela.debug_foo {
diff --git a/llvm/test/tools/llvm-objcopy/ELF/group-reorder.test b/llvm/test/tools/llvm-objcopy/ELF/group-reorder.test
new file mode 100644
index 0000000..25d0cd5
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/ELF/group-reorder.test
@@ -0,0 +1,64 @@
+# RUN: yaml2obj %s > %t.o
+# RUN: llvm-objcopy %t.o %t.2.o
+# RUN: llvm-readelf --elf-section-groups --sections %t.o | FileCheck %s --check-prefix=IN
+# RUN: llvm-readelf --elf-section-groups --sections %t.2.o | FileCheck %s --check-prefix=OUT
+
+# In this test, .group gets moved to the beginning. Run readelf -gS on input as
+# well as output to make sure it really moved, as well as to verify that we
+# aren't purely sorting based on offsets (it gets moved to the beginning
+# despite having a larger offset).
+
+# IN: There are 7 section headers, starting at offset 0x40:
+# IN: [Nr] Name Type Address Off Size
+# IN-NEXT: [ 0] NULL 0000000000000000 000000 000000
+# IN-NEXT: [ 1] .foo PROGBITS 0000000000000000 000200 000040
+# IN-NEXT: [ 2] .group GROUP 0000000000000000 000240 000008
+# IN-NEXT: [ 3] .bar PROGBITS 0000000000000000 000248 000040
+
+# IN: COMDAT group section [ 2] `.group' [bar] contains 1 sections:
+# IN-NEXT: [Index] Name
+# IN-NEXT: [ 3] .bar
+
+# OUT: There are 7 section headers, starting at offset 0x160:
+# OUT: [Nr] Name Type Address Off Size
+# OUT-NEXT: [ 0] NULL 0000000000000000 000000 000000
+# OUT-NEXT: [ 1] .group GROUP 0000000000000000 000040 000008
+# OUT-NEXT: [ 2] .foo PROGBITS 0000000000000000 000048 000040
+# OUT-NEXT: [ 3] .bar PROGBITS 0000000000000000 000088 000040
+
+# OUT: COMDAT group section [ 1] `.group' [bar] contains 1 sections:
+# OUT-NEXT: [Index] Name
+# OUT-NEXT: [ 3] .bar
+
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+Sections:
+ - Name: .foo
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ Size: 64
+ - Name: .group
+ Type: SHT_GROUP
+ Link: .symtab
+ Info: bar
+ Members:
+ - SectionOrType: GRP_COMDAT
+ - SectionOrType: .bar
+ - Name: .bar
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+ Size: 64
+Symbols:
+ - Name: .foo
+ Type: STT_SECTION
+ Section: .foo
+ - Name: .bar
+ Type: STT_SECTION
+ Section: .bar
+ - Name: bar
+ Type: STT_FUNC
+ Section: .foo
diff --git a/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test b/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test
index 724b063..6404bba 100644
--- a/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test
+++ b/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test
@@ -27,14 +27,14 @@
// Link, Info and the content of this section.
CHECK: Name: .group (179)
-CHECK-NEXT: Index: 17
+CHECK-NEXT: Index: 1{{$}}
CHECK-NEXT: Link: 19
CHECK-NEXT: Info: 14
-CHECK: .text._ZN1SIiE4getXEv (2)
+CHECK: .text._ZN1SIiE4getXEv
CHECK: Name: .group (179)
-CHECK-NEXT: Index: 18
+CHECK-NEXT: Index: 2{{$}}
CHECK-NEXT: Link: 19
CHECK-NEXT: Info: 13
-CHECK: .text._ZN1SIdE4getXEv (4)
-CHECK-NEXT: .rela.text._ZN1SIdE4getXEv (21)
+CHECK: .text._ZN1SIdE4getXEv
+CHECK-NEXT: .rela.text._ZN1SIdE4getXEv