[llvm-objcopy] - Reimplement strip-dwo-groups.test to stop using the precompiled object.

[grimar]

Summary

When llvm-copy removes .dwo sections the index of symbol table,
the indices of the symbols and the indices of the sections which go
after the removed ones changes. That affects on SHT_GROUP sections,
which needs to be updated.

Initially this test used a precompiled object, I rewrote it to use YAML
and improved a bit.

[MaskRay]

test/tools/llvm-objcopy/ELF/strip-dwo-groups.test

5–11

The comment may be too verbose. Suggested wording (please improve as you rewrite :) ):

After the removal of .dwo sections, the indices of sections which go after them will change. Check that the sh_link and sh_info fields of .group and their contents (indices of member sections) are updated.

69

Delete the empty Relocations:

[jhenderson]

LGTM, once @MaskRay's comments have been addressed.

[grimar]

• Addressed review comments.

test/tools/llvm-objcopy/ELF/strip-dwo-groups.test

5–11

Your version looks OK to me.

But I do not feel that "too verbose" is a problem,
I like to read the description of the problem and the details.
Unfortunately often svn/git commit comments are the only source.
"too verbose" is in my understanding can be used for the code comments,
but while we are in the test cases area, If you do not mind, I would keep it verbose.

69

Done (I thought this is a mandatory field, but it is not).

[MaskRay]

test/tools/llvm-objcopy/ELF/strip-dwo-groups.test

5–11

Unfortunately often svn/git commit comments are the only source.

Agreed.

"too verbose" is in my understanding can be used for the code comments, but while we are in the test cases area, If you do not mind, I would keep it verbose.

I am fine with the current version but I feel we can convey the same information while making it more concise. For example, we don't have to emphasize the previous bug:

In the past llvm-objcopy --strip-dwo used to produce invalid binaries with broken .group section, this test verifies the correctness of Link, Info and the content of this section.

The expected behavior is kind of self-explanatory with the existence of the test.

their contents (indices of member sections) are updated.

It emphasizes the purpose updating the contents.

[grimar]

test/tools/llvm-objcopy/ELF/strip-dwo-groups.test

5–11

For example, we don't have to emphasize the previous bug

Sometimes the description of the previous bug can be helpful, but I agree with you that here it is not.
I'll remove the part that starts from "In the past..." before the commit.

[grimar]

Revision: 367202

[gchatelet]

The test appears to fail when the compilation path contains the debug_ substring.
This is not ideal.

FAIL: LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test (1254 of 2021)
******************** TEST 'LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test' FAILED ********************
Script:
--
: 'RUN: at line 1';   /tmp/llvm-project_debug_compiled-with-clang/bin/yaml2obj /redacted/llvm-project/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test -o /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
: 'RUN: at line 2';   /tmp/llvm-project_debug_compiled-with-clang/bin/llvm-objcopy --strip-dwo /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
: 'RUN: at line 3';   /tmp/llvm-project_debug_compiled-with-clang/bin/llvm-readobj --symbols -S --elf-section-groups /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp | /tmp/llvm-project_debug_compiled-with-clang/bin/FileCheck /redacted/llvm-project/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test --implicit-check-not=debug_
--
Exit Code: 1

Command Output (stderr):
--
command line:1:22: error: CHECK-NOT: excluded string found in input
-implicit-check-not='debug_'
                     ^
<stdin>:2:25: note: found here
File: /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
                        ^~~~~~

--

********************
Testing Time: 6.87s
********************
Failing Tests (1):
    LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test

[grimar]

In D65273#1612246, @gchatelet wrote:

The test appears to fail when the compilation path contains the debug_ substring.
This is not ideal.

FAIL: LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test (1254 of 2021)
******************** TEST 'LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test' FAILED ********************
Script:
--
: 'RUN: at line 1';   /tmp/llvm-project_debug_compiled-with-clang/bin/yaml2obj /redacted/llvm-project/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test -o /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
: 'RUN: at line 2';   /tmp/llvm-project_debug_compiled-with-clang/bin/llvm-objcopy --strip-dwo /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
: 'RUN: at line 3';   /tmp/llvm-project_debug_compiled-with-clang/bin/llvm-readobj --symbols -S --elf-section-groups /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp | /tmp/llvm-project_debug_compiled-with-clang/bin/FileCheck /redacted/llvm-project/llvm/test/tools/llvm-objcopy/ELF/strip-dwo-groups.test --implicit-check-not=debug_
--
Exit Code: 1

Command Output (stderr):
--
command line:1:22: error: CHECK-NOT: excluded string found in input
-implicit-check-not='debug_'
                     ^
<stdin>:2:25: note: found here
File: /tmp/llvm-project_debug_compiled-with-clang/test/tools/llvm-objcopy/ELF/Output/strip-dwo-groups.test.tmp
                        ^~~~~~

--

********************
Testing Time: 6.87s
********************
Failing Tests (1):
    LLVM :: tools/llvm-objcopy/ELF/strip-dwo-groups.test

Thanks for reporting! I committed rL367702, it should fix this.

test/tools/llvm-objcopy/ELF/strip-dwo-groups.test

-# RUN: cp %p/Inputs/groups.o %t
+# RUN: yaml2obj %s -o %t
 # RUN: llvm-objcopy --strip-dwo %t
-# RUN: llvm-readobj --elf-section-groups %t | FileCheck %s
+# RUN: llvm-readobj --symbols -S --elf-section-groups %t | FileCheck %s --implicit-check-not=debug_
 
-// Source code of groups.o:
-//
-// template <class T>
-// struct S {
-//    static constexpr T X = T(1);
-//    T getX() { return X; }
-// };
-// void f() {
-//  S<int> A;
-//  S<double> B;
-//  int a = A.getX();
-//  int b = B.getX();
-// }
-//
-// clang -g -gsplit-dwarf -std=c++11 -c groups.cpp -o groups.o
+## `llvm-objcopy --strip-dwo` strips out dwo sections, as a result, the index of 
+## the symbol table, the indices of the symbols and the indices of the sections
+## which go after the removed ones will change. Consequently, the fields 
+## Link, Info and the content of .group need to be updated. In the past 
+## `llvm-objcopy --strip-dwo` used to produce invalid binaries with 
+## broken .group section, this test verifies the correctness of 
+## Link, Info and the content of this section.
 
-// `llvm-objcopy --strip-dwo` strips out dwo sections, as a result, the index of 
-// the symbol table, the indices of the symbols and the indices of the sections 
-// which go after the removed ones will change. Consequently, the fields 
-// Link, Info and the content of .group need to be updated. In the past 
-// `llvm-objcopy --strip-dwo` used to produce invalid binaries with 
-// broken .group section, this test verifies the correctness of 
-// Link, Info and the content of this section.
+# CHECK:      Groups {
+# CHECK:       Name: .group (1)
+# CHECK-NEXT:  Index: 1{{$}}
+# CHECK-NEXT:  Link: 6
+# CHECK-NEXT:  Info: 2
+# CHECK-NEXT:  Type: COMDAT (0x1)
+# CHECK-NEXT:  Signature: group1
+# CHECK-NEXT:  Section(s) in group [
+# CHECK-NEXT:    .text.group1 (3)
+# CHECK-NEXT:  ]
 
-CHECK:          Name: .group (179)
-CHECK-NEXT:     Index: 1{{$}}
-CHECK-NEXT:     Link: 19
-CHECK-NEXT:     Info: 14
-CHECK:          .text._ZN1SIiE4getXEv
+# CHECK:      Name: .group (1)
+# CHECK-NEXT: Index: 2{{$}}
+# CHECK-NEXT: Link: 6
+# CHECK-NEXT: Info: 1
+# CHECK-NEXT: Type: COMDAT (0x1)
+# CHECK-NEXT: Signature: group2
+# CHECK-NEXT: Section(s) in group [
+# CHECK-NEXT:   .text.group2 (4)
+# CHECK-NEXT:   .rela.text.group2 (5)
+# CHECK-NEXT: ]
 
-CHECK:          Name: .group (179)
-CHECK-NEXT:     Index: 2{{$}}
-CHECK-NEXT:     Link: 19
-CHECK-NEXT:     Info: 13
-CHECK:          .text._ZN1SIdE4getXEv
-CHECK-NEXT:     .rela.text._ZN1SIdE4getXEv
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_X86_64
+Sections:
+  - Name: .debug_before.dwo
+    Type: SHT_PROGBITS
+  - Name: .group
+    Type: SHT_GROUP
+    Link: .symtab
+    Info: group1
+    Members:
+      - SectionOrType: GRP_COMDAT
+      - SectionOrType: .text.group1
+  - Name:  .text.group1
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+  - Name: '.group [1]'
+    Type: SHT_GROUP
+    Link: .symtab
+    Info: group2
+    Members:
+      - SectionOrType: GRP_COMDAT
+      - SectionOrType: .text.group2
+      - SectionOrType: .rela.text.group2
+  - Name:  .text.group2
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]
+  - Name:  .rela.text.group2
+    Type:  SHT_RELA
+    Flags: [ SHF_GROUP ]
+    Info:  .text.group2
+  - Name: .debug_after.dwo
+    Type: SHT_PROGBITS
+Symbols:
+  - Name:    debug_before
+    Section: .debug_before.dwo
+  - Name:    group2
+    Section: .text.group2
+  - Name:    group1
+    Section: .text.group1
+  - Name:    debug_after
+    Section: .debug_after.dwo