Fortran and assembly
Reference: https://gcc.gnu.org/wiki/GFortranHacking
%%writefile hello.f90
program hello
print *, "Hello World!"
end program
Writing hello.f90
! gfortran hello.f90
! ./a.out
Hello World!
! gfortran -S hello.f90
! cat hello.s
.file "hello.f90"
.text
.section .rodata
.LC0:
.string "hello.f90"
.LC1:
.ascii "Hello World!"
.text
.type MAIN__, @function
MAIN__:
.LFB0:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
subq $528, %rsp
movq $.LC0, -520(%rbp)
movl $2, -512(%rbp)
movl $128, -528(%rbp)
movl $6, -524(%rbp)
leaq -528(%rbp), %rax
movq %rax, %rdi
call _gfortran_st_write
leaq -528(%rbp), %rax
movl $12, %edx
movl $.LC1, %esi
movq %rax, %rdi
call _gfortran_transfer_character_write
leaq -528(%rbp), %rax
movq %rax, %rdi
call _gfortran_st_write_done
nop
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE0:
.size MAIN__, .-MAIN__
.globl main
.type main, @function
main:
.LFB1:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp
.cfi_def_cfa_register 6
subq $16, %rsp
movl %edi, -4(%rbp)
movq %rsi, -16(%rbp)
movq -16(%rbp), %rdx
movl -4(%rbp), %eax
movq %rdx, %rsi
movl %eax, %edi
call _gfortran_set_args
movl $options.1.0, %esi
movl $7, %edi
call _gfortran_set_options
call MAIN__
movl $0, %eax
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE1:
.size main, .-main
.section .rodata
.align 16
.type options.1.0, @object
.size options.1.0, 28
options.1.0:
.long 2116
.long 4095
.long 0
.long 1
.long 1
.long 0
.long 31
.ident "GCC: (GNU) 10.2.1 20201125 (Red Hat 10.2.1-9)"
.section .note.GNU-stack,"",@progbits
! gfortran -S -fverbose-asm -fdump-tree-original-uid -fdump-tree-optimized-uid hello.f90
! cat hello.s
.file "hello.f90"
# GNU Fortran2008 (GCC) version 10.2.1 20201125 (Red Hat 10.2.1-9) (x86_64-redhat-linux)
# compiled by GNU C version 10.2.1 20201125 (Red Hat 10.2.1-9), GMP version 6.2.0, MPFR version 4.1.0, MPC version 1.1.0, isl version none
# warning: MPFR header version 4.1.0 differs from library version 4.1.0-p9.
# GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
# options passed: hello.f90 -mtune=generic -march=x86-64 -fverbose-asm
# -fdump-tree-original-uid -fdump-tree-optimized-uid
# -fintrinsic-modules-path /usr/lib/gcc/x86_64-redhat-linux/10/finclude
# -fpre-include=/usr/include/finclude/math-vector-fortran.h
# options enabled: -faggressive-loop-optimizations -fallocation-dce
# -fasynchronous-unwind-tables -fauto-inc-dec -fdelete-null-pointer-checks
# -fdwarf2-cfi-asm -fearly-inlining -feliminate-unused-debug-symbols
# -feliminate-unused-debug-types -ffp-int-builtin-inexact -ffunction-cse
# -fgcse-lm -fgnu-unique -fident -finline-atomics -fipa-stack-alignment
# -fira-hoist-pressure -fira-share-save-slots -fira-share-spill-slots
# -fivopts -fkeep-static-consts -fleading-underscore -flifetime-dse
# -fmerge-debug-strings -fpeephole -fplt -fprefetch-loop-arrays
# -freg-struct-return -fsched-critical-path-heuristic
# -fsched-dep-count-heuristic -fsched-group-heuristic -fsched-interblock
# -fsched-last-insn-heuristic -fsched-rank-heuristic -fsched-spec
# -fsched-spec-insn-heuristic -fsched-stalled-insns-dep -fschedule-fusion
# -fsemantic-interposition -fshow-column -fshrink-wrap-separate
# -fsigned-zeros -fsplit-ivs-in-unroller -fssa-backprop -fstdarg-opt
# -fstrict-volatile-bitfields -fsync-libcalls -ftrapping-math -ftree-cselim
# -ftree-forwprop -ftree-loop-if-convert -ftree-loop-im -ftree-loop-ivcanon
# -ftree-loop-optimize -ftree-parallelize-loops= -ftree-phiprop
# -ftree-reassoc -ftree-scev-cprop -funit-at-a-time -funwind-tables
# -fverbose-asm -fzero-initialized-in-bss -m128bit-long-double -m64 -m80387
# -malign-stringops -mavx256-split-unaligned-load
# -mavx256-split-unaligned-store -mfancy-math-387 -mfp-ret-in-387 -mfxsr
# -mglibc -mieee-fp -mlong-double-80 -mmmx -mno-sse4 -mpush-args -mred-zone
# -msse -msse2 -mstv -mtls-direct-seg-refs -mvzeroupper
.text
.section .rodata
.LC0:
.string "hello.f90"
.LC1:
.ascii "Hello World!"
.text
.type MAIN__, @function
MAIN__:
.LFB0:
.cfi_startproc
pushq %rbp #
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp #,
.cfi_def_cfa_register 6
subq $528, %rsp #,
# hello.f90:2: print *, "Hello World!"
movq $.LC0, -520(%rbp) #, dt_parm.0.common.filename
movl $2, -512(%rbp) #, dt_parm.0.common.line
movl $128, -528(%rbp) #, dt_parm.0.common.flags
movl $6, -524(%rbp) #, dt_parm.0.common.unit
leaq -528(%rbp), %rax #, tmp82
movq %rax, %rdi # tmp82,
call _gfortran_st_write #
leaq -528(%rbp), %rax #, tmp83
movl $12, %edx #,
movl $.LC1, %esi #,
movq %rax, %rdi # tmp83,
call _gfortran_transfer_character_write #
leaq -528(%rbp), %rax #, tmp84
movq %rax, %rdi # tmp84,
call _gfortran_st_write_done #
# hello.f90:3: end program
nop
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE0:
.size MAIN__, .-MAIN__
.globl main
.type main, @function
main:
.LFB1:
.cfi_startproc
pushq %rbp #
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq %rsp, %rbp #,
.cfi_def_cfa_register 6
subq $16, %rsp #,
movl %edi, -4(%rbp) # argc, argc
movq %rsi, -16(%rbp) # argv, argv
# hello.f90:3: end program
movq -16(%rbp), %rdx # argv, tmp84
movl -4(%rbp), %eax # argc, tmp85
movq %rdx, %rsi # tmp84,
movl %eax, %edi # tmp85,
call _gfortran_set_args #
movl $options.1.0, %esi #,
movl $7, %edi #,
call _gfortran_set_options #
call MAIN__ #
movl $0, %eax #, _7
leave
.cfi_def_cfa 7, 8
ret
.cfi_endproc
.LFE1:
.size main, .-main
.section .rodata
.align 16
.type options.1.0, @object
.size options.1.0, 28
options.1.0:
.long 2116
.long 4095
.long 0
.long 1
.long 1
.long 0
.long 31
.ident "GCC: (GNU) 10.2.1 20201125 (Red Hat 10.2.1-9)"
.section .note.GNU-stack,"",@progbits