[Pkg-pascal-devel] Bug#1038868: fpc: armhf binaries should have the hard-float ELF flag set

[Emanuele Rocca]

Package: fpc
Version: 3.2.2+dfsg-21

Hi,

binaries produced by fpc on armhf currently lack the hard-float ELF
flag.

I've built the following hello world program with `fpc hello.pas`:

 program Hello;
 begin
   writeln ('Hello, world.');
 end.

The resulting ELF object looks like this, note in particular the value
of "Flags", namely "0x5000200, Version5 EABI, soft-float ABI". This
should be "0x5000400, Version5 EABI, hard-float ABI" instead.

$ readelf -h hello
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x100ec
  Start of program headers:          52 (bytes into file)
  Start of section headers:          231208 (bytes into file)
  Flags:                             0x5000200, Version5 EABI, soft-float ABI
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         4
  Size of section headers:           40 (bytes)
  Number of section headers:         10
  Section header string table index: 9

Compare with a C hello world program built with `gcc hello.c`, and again
note the value of Flags: "0x5000400, Version5 EABI, hard-float ABI".

ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              DYN (Position-Independent Executable file)
  Machine:                           ARM
  Version:                           0x1
  Entry point address:               0x409
  Start of program headers:          52 (bytes into file)
  Start of section headers:          6692 (bytes into file)
  Flags:                             0x5000400, Version5 EABI, hard-float ABI
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         9
  Size of section headers:           40 (bytes)
  Number of section headers:         29

Additionally, the attribute "Tag_ABI_VFP_args" should be set to "VFP registers".

$ readelf -A hello
Attribute Section: aeabi
File Attributes
  Tag_CPU_arch: v4T
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-1

And compare with the attributes in the ELF file produced by GCC:

$ readelf -A a.out 
Attribute Section: aeabi
File Attributes
  Tag_CPU_name: "7-A"
  Tag_CPU_arch: v7
  Tag_CPU_arch_profile: Application
  Tag_ARM_ISA_use: Yes
  Tag_THUMB_ISA_use: Thumb-2
  Tag_FP_arch: VFPv3-D16
  Tag_ABI_PCS_wchar_t: 4
  Tag_ABI_FP_rounding: Needed
  Tag_ABI_FP_denormal: Needed
  Tag_ABI_FP_exceptions: Needed
  Tag_ABI_FP_number_model: IEEE 754
  Tag_ABI_align_needed: 8-byte
  Tag_ABI_align_preserved: 8-byte, except leaf SP
  Tag_ABI_enum_size: int
  Tag_ABI_VFP_args: VFP registers
  Tag_CPU_unaligned_access: v6