[llvm-readobj][llvm-readelf] - Refactor parsing of the SHT_GNU_versym section.

This introduce a new helper which is used to parse the SHT_GNU_versym section.
LLVM/GNU styles implementations now use it to share the logic.

Differential revision: https://reviews.llvm.org/D71054

4 files changed, 225 insertions, 3 deletions

diff --git a/llvm/test/tools/llvm-readobj/all.test b/llvm/test/tools/llvm-readobj/all.test
index 5edda0af1f9..1f617034d0e 100644
--- a/llvm/test/tools/llvm-readobj/all.test
+++ b/llvm/test/tools/llvm-readobj/all.test
@@ -53,6 +53,7 @@ Sections:
   - Name:    .gnu.version
     Type:    SHT_GNU_versym
     Entries: [ 0 ]
+    Link:    .dynsym
   - Name:    .gnu.version_d
     Type:    SHT_GNU_verdef
     Info:    0x0
@@ -111,3 +112,4 @@ ProgramHeaders:
     Sections:
       - Section: .note.gnu.build-id
 Symbols: []
+DynamicSymbols: []
diff --git a/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test b/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
index 2eb262f555c..f80e9383f70 100644
--- a/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
+++ b/llvm/test/tools/llvm-readobj/elf-verdef-invalid.test
@@ -275,6 +275,7 @@ DynamicSymbols:
 # INVALID-VERDEF-LLVM-NEXT:      Name:
 # INVALID-VERDEF-LLVM-NEXT:    }
 # INVALID-VERDEF-LLVM-NEXT:    Symbol {
+# INVALID-VERDEF-LLVM-NEXT:    Version: 2
 # INVALID-VERDEF-LLVM-EMPTY:
 # INVALID-VERDEF-LLVM-NEXT:  error: '[[FILE]]': invalid SHT_GNU_verdef section with index 2: version definition 1 goes past the end of the section
 
diff --git a/llvm/test/tools/llvm-readobj/elf-verneed-invalid.test b/llvm/test/tools/llvm-readobj/elf-verneed-invalid.test
index 6a04519a05d..e8d75afe1e6 100644
--- a/llvm/test/tools/llvm-readobj/elf-verneed-invalid.test
+++ b/llvm/test/tools/llvm-readobj/elf-verneed-invalid.test
@@ -101,9 +101,9 @@ DynamicSymbols:
 # LLVM-NOLINK-NEXT:     Name:
 # LLVM-NOLINK-NEXT:   }
 # LLVM-NOLINK-NEXT:   Symbol {
+# LLVM-NOLINK-NEXT:     Version: 2
 # LLVM-NOLINK-EMPTY:
 # LLVM-NOLINK-NEXT:  warning: '[[FILE]]': invalid string table linked to SHT_GNU_verneed section with index 2: invalid sh_type for string table section [index 0]: expected SHT_STRTAB, but got SHT_NULL
-# LLVM-NOLINK-NEXT:     Version: 2
 # LLVM-NOLINK-NEXT:     Name: foo@<corrupt>
 # LLVM-NOLINK-NEXT:   }
 # LLVM-NOLINK-NEXT: ]
@@ -183,8 +183,7 @@ Sections:
     AddressAlign: 4
 ## The byte offset to the auxiliary entry is 0x11, i.e. it is not correctly aligned in memory.
     Content: "0100010001000000110000000000000000000000"
-DynamicSymbols:
-  - Name: foo
+DynamicSymbols: []
 
 ## Here we check that we can properly dump the case when a dependency file name
 ## and/or a dependency name string offset is equal to the string table size.
diff --git a/llvm/test/tools/llvm-readobj/elf-versym-invalid.test b/llvm/test/tools/llvm-readobj/elf-versym-invalid.test
new file mode 100644
index 00000000000..a88318e5f49
--- /dev/null
+++ b/llvm/test/tools/llvm-readobj/elf-versym-invalid.test
@@ -0,0 +1,220 @@
+## Test how llvm-readobj/llvm-readelf tools handle invalid SHT_GNU_versym sections.
+
+## Check that we report a warning when sh_link references a non-existent section.
+
+# RUN: yaml2obj --docnum=1 %s -o %t1
+# RUN: llvm-readelf -V %t1 2>&1 | FileCheck -DFILE=%t1 %s --check-prefix=GNU-INVALID-LINK
+# RUN: llvm-readobj -V %t1 2>&1 | FileCheck -DFILE=%t1 %s --check-prefix=LLVM-INVALID-LINK
+
+# GNU-INVALID-LINK:       Version symbols section '.gnu.version' contains 0 entries:
+# GNU-INVALID-LINK-EMPTY:
+# GNU-INVALID-LINK-NEXT:  warning: '[[FILE]]': invalid section linked to SHT_GNU_versym section with index 1: invalid section index: 255
+# GNU-INVALID-LINK-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 255 (<corrupt>)
+
+# LLVM-INVALID-LINK:       VersionSymbols [
+# LLVM-INVALID-LINK-EMPTY:
+# LLVM-INVALID-LINK-NEXT:  warning: '[[FILE]]': invalid section linked to SHT_GNU_versym section with index 1: invalid section index: 255
+# LLVM-INVALID-LINK-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Link:    0xFF
+    Entries: [ ]
+
+## Check that we report a warning when the sh_link field of a SHT_GNU_versym section does not reference
+## a dynamic symbol table section.
+
+# RUN: yaml2obj --docnum=2 %s -o %t2
+# RUN: llvm-readelf -V %t2 2>&1 | FileCheck -DFILE=%t2 %s --check-prefix=INVALID-SYMBOL-TABLE-GNU
+# RUN: llvm-readobj -V %t2 2>&1 | FileCheck -DFILE=%t2 %s --check-prefix=INVALID-SYMBOL-TABLE-LLVM
+
+# INVALID-SYMBOL-TABLE-GNU:       Version symbols section '.gnu.version' contains 1 entries:
+# INVALID-SYMBOL-TABLE-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 0 ()
+# INVALID-SYMBOL-TABLE-GNU-EMPTY:
+# INVALID-SYMBOL-TABLE-GNU-NEXT:   warning: '[[FILE]]': invalid section linked to SHT_GNU_versym section with index 1: expected SHT_DYNSYM, but got SHT_NULL
+# INVALID-SYMBOL-TABLE-GNU-NEXT:   000:   0 (*local*)
+
+# INVALID-SYMBOL-TABLE-LLVM:       VersionSymbols [
+# INVALID-SYMBOL-TABLE-LLVM-EMPTY:
+# INVALID-SYMBOL-TABLE-LLVM-NEXT:  warning: '[[FILE]]': invalid section linked to SHT_GNU_versym section with index 1: expected SHT_DYNSYM, but got SHT_NULL
+# INVALID-SYMBOL-TABLE-LLVM-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Link:    0x0
+    Entries: [ 0 ]
+
+## Check we report a warning when something is wrong with a string table linked to a symbol table that
+## is linked with SHT_GNU_versym. In this case we are unable to produce LLVM style output,
+## but GNU style is fine because it does not need that string table.
+
+# RUN: yaml2obj --docnum=3 %s -o %t3
+# RUN: llvm-readelf -V %t3 2>&1 | FileCheck -DFILE=%t3 %s --check-prefix=INVALID-STRING-TABLE-GNU
+# RUN: llvm-readobj -V %t3 2>&1 | FileCheck -DFILE=%t3 %s --check-prefix=INVALID-STRING-TABLE-LLVM
+
+# INVALID-STRING-TABLE-GNU:       Version symbols section '.gnu.version' contains 1 entries:
+# INVALID-STRING-TABLE-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 5 (.dynsym)
+# INVALID-STRING-TABLE-GNU-EMPTY:
+# INVALID-STRING-TABLE-GNU-NEXT:   warning: '[[FILE]]': can't get a string table for the symbol table linked to SHT_GNU_versym section with index 1: invalid string table linked to SHT_DYNSYM section with index 5: invalid sh_type for string table section [index 2]: expected SHT_STRTAB, but got SHT_NULL
+# INVALID-STRING-TABLE-GNU-NEXT:   000:   0 (*local*)
+
+# INVALID-STRING-TABLE-LLVM:       VersionSymbols [
+# INVALID-STRING-TABLE-LLVM-EMPTY:
+# INVALID-STRING-TABLE-LLVM-NEXT:  warning: '[[FILE]]': can't get a string table for the symbol table linked to SHT_GNU_versym section with index 1: invalid string table linked to SHT_DYNSYM section with index 5: invalid sh_type for string table section [index 2]: expected SHT_STRTAB, but got SHT_NULL
+# INVALID-STRING-TABLE-LLVM-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Link:    .dynsym
+    Entries: [ 0 ]
+  - Name:    .dynstr
+    Type:    SHT_NULL
+DynamicSymbols: []
+
+## Check we report a warning when a SHT_GNU_versym section is not correctly aligned in memory.
+
+# RUN: yaml2obj --docnum=4 %s -o %t4
+# RUN: llvm-readelf -V %t4 2>&1 | FileCheck -DFILE=%t4 %s --check-prefix=MISALIGNED-GNU
+# RUN: llvm-readobj -V %t4 2>&1 | FileCheck -DFILE=%t4 %s --check-prefix=MISALIGNED-LLVM
+
+# MISALIGNED-GNU:       Version symbols section '.gnu.version' contains 0 entries:
+# MISALIGNED-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x00ffff  Link: 0 ()
+# MISALIGNED-GNU-EMPTY:
+# MISALIGNED-GNU-NEXT:   warning: '[[FILE]]': the SHT_GNU_versym section with index 1 is misaligned
+
+# MISALIGNED-LLVM:       VersionSymbols [
+# MISALIGNED-LLVM-EMPTY:
+# MISALIGNED-LLVM-NEXT:   warning: '[[FILE]]': the SHT_GNU_versym section with index 1 is misaligned
+# MISALIGNED-LLVM-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Entries: [ ]
+    ShOffset: 0xffff
+
+## Check we report a warning when a SHT_GNU_versym section has an invalid entry size.
+
+# RUN: yaml2obj --docnum=5 %s -o %t5
+# RUN: llvm-readelf -V %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-GNU
+# RUN: llvm-readobj -V %t5 2>&1 | FileCheck -DFILE=%t5 %s --check-prefix=INVALID-ENT-SIZE-LLVM
+
+# INVALID-ENT-SIZE-GNU:       Version symbols section '.gnu.version' contains 1 entries:
+# INVALID-ENT-SIZE-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 0 ()
+# INVALID-ENT-SIZE-GNU-EMPTY:
+# INVALID-ENT-SIZE-GNU-NEXT:  warning: '[[FILE]]': cannot read content of SHT_GNU_versym section with index 1: section [index 1] has an invalid sh_entsize: 3
+
+# INVALID-ENT-SIZE-LLVM:       VersionSymbols [
+# INVALID-ENT-SIZE-LLVM-EMPTY:
+# INVALID-ENT-SIZE-LLVM-NEXT:  warning: '[[FILE]]': cannot read content of SHT_GNU_versym section with index 1: section [index 1] has an invalid sh_entsize: 3
+# INVALID-ENT-SIZE-LLVM-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Entries: [ 0 ]
+    EntSize: 3
+
+## Check we report a warning when the number of version entries does not match the number of symbols in the associated symbol table.
+
+# RUN: yaml2obj --docnum=6 %s -o %t6
+# RUN: llvm-readelf -V %t6 2>&1 | FileCheck -DFILE=%t6 %s --check-prefix=SYMBOLS-NUM-MISMATCH-GNU
+# RUN: llvm-readobj -V %t6 2>&1 | FileCheck -DFILE=%t6 %s --check-prefix=SYMBOLS-NUM-MISMATCH-LLVM
+
+# SYMBOLS-NUM-MISMATCH-GNU:       Version symbols section '.gnu.version' contains 2 entries:
+# SYMBOLS-NUM-MISMATCH-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 4 (.dynsym)
+# SYMBOLS-NUM-MISMATCH-GNU-EMPTY:
+# SYMBOLS-NUM-MISMATCH-GNU-NEXT:   warning: '[[FILE]]': SHT_GNU_versym section with index 1: the number of entries (2) does not match the number of symbols (3) in the symbol table with index 4
+# SYMBOLS-NUM-MISMATCH-GNU-NEXT:    000:   0 (*local*)       1 (*global*)
+
+# SYMBOLS-NUM-MISMATCH-LLVM:       VersionSymbols [
+# SYMBOLS-NUM-MISMATCH-LLVM-EMPTY:
+# SYMBOLS-NUM-MISMATCH-LLVM-NEXT:  warning: '[[FILE]]': SHT_GNU_versym section with index 1: the number of entries (2) does not match the number of symbols (3) in the symbol table with index 4
+# SYMBOLS-NUM-MISMATCH-LLVM-NEXT:  ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Entries: [ 0, 1 ]
+    Link:   .dynsym
+DynamicSymbols:
+  - Name: foo
+  - Name: bar
+
+## Check we can dump a SHT_GNU_versym section when it is linked to a custom dynamic symbol
+## table that is not called ".dynsym".
+
+# RUN: yaml2obj --docnum=7 %s -o %t7
+# RUN: llvm-readelf -V %t7 2>&1 | FileCheck -DFILE=%t7 %s --check-prefix=CUSTOM-SYMTAB-GNU
+# RUN: llvm-readobj -V %t7 2>&1 | FileCheck -DFILE=%t7 %s --check-prefix=CUSTOM-SYMTAB-LLVM
+
+# CUSTOM-SYMTAB-GNU:      Version symbols section '.gnu.version' contains 1 entries:
+# CUSTOM-SYMTAB-GNU-NEXT:   Addr: 0000000000000000  Offset: 0x000040  Link: 2 (.foo.dynsym)
+# CUSTOM-SYMTAB-GNU-NEXT:    000:   0 (*local*)
+
+# CUSTOM-SYMTAB-LLVM:      VersionSymbols [
+# CUSTOM-SYMTAB-LLVM-NEXT:  Symbol {
+# CUSTOM-SYMTAB-LLVM-NEXT:    Version: 0
+# CUSTOM-SYMTAB-LLVM-NEXT:    Name:
+# CUSTOM-SYMTAB-LLVM-NEXT:  }
+# CUSTOM-SYMTAB-LLVM-NEXT: ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .gnu.version
+    Type:    SHT_GNU_versym
+    Link:    .foo.dynsym
+    Entries: [ 0 ]
+## A custom empty dynamic symbol table with a null entry.
+  - Name:    .foo.dynsym
+    Type:    SHT_DYNSYM
+    Link:    .dynstr
+    EntSize: 24
+    Size:    24
+DynamicSymbols:
+  - Name: foo
+  - Name: bar