ocaml/asmcomp/amd64/proc.ml

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OCaml

# 2 "asmcomp/amd64/proc.ml"
(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 2000 Institut National de Recherche en Informatique et *)
(* en Automatique. *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
(* Description of the AMD64 processor *)
open Misc
open Arch
open Cmm
open Reg
open Mach
let fp = Config.with_frame_pointers
(* Which ABI to use *)
let win64 = Arch.win64
(* Registers available for register allocation *)
(* Register map:
rax 0
rbx 1
rdi 2
rsi 3
rdx 4
rcx 5
r8 6
r9 7
r12 8
r13 9
r10 10
r11 11
rbp 12
r14 domain state pointer
r15 allocation pointer
xmm0 - xmm15 100 - 115 *)
(* Conventions:
rax - r13: OCaml function arguments
rax: OCaml and C function results
xmm0 - xmm9: OCaml function arguments
xmm0: OCaml and C function results
Under Unix:
rdi, rsi, rdx, rcx, r8, r9: C function arguments
xmm0 - xmm7: C function arguments
rbx, rbp, r12-r15 are preserved by C
xmm registers are not preserved by C
Under Win64:
rcx, rdx, r8, r9: C function arguments
xmm0 - xmm3: C function arguments
rbx, rbp, rsi, rdi r12-r15 are preserved by C
xmm6-xmm15 are preserved by C
Note (PR#5707, GPR#1304): PLT stubs (used for dynamic resolution of symbols
on Unix-like platforms) may clobber any register except those used for:
1. C parameter passing;
2. C return values;
3. C callee-saved registers.
This translates to the set { r10, r11 }. These registers hence cannot
be used for OCaml parameter passing and must also be marked as
destroyed across [Ialloc] (otherwise a call to caml_call_gc@PLT might
clobber these two registers before the assembly stub saves them into
the GC regs block).
*)
let max_arguments_for_tailcalls = 10
let int_reg_name =
match Config.ccomp_type with
| "msvc" ->
[| "rax"; "rbx"; "rdi"; "rsi"; "rdx"; "rcx"; "r8"; "r9";
"r12"; "r13"; "r10"; "r11"; "rbp" |]
| _ ->
[| "%rax"; "%rbx"; "%rdi"; "%rsi"; "%rdx"; "%rcx"; "%r8"; "%r9";
"%r12"; "%r13"; "%r10"; "%r11"; "%rbp" |]
let float_reg_name =
match Config.ccomp_type with
| "msvc" ->
[| "xmm0"; "xmm1"; "xmm2"; "xmm3"; "xmm4"; "xmm5"; "xmm6"; "xmm7";
"xmm8"; "xmm9"; "xmm10"; "xmm11";
"xmm12"; "xmm13"; "xmm14"; "xmm15" |]
| _ ->
[| "%xmm0"; "%xmm1"; "%xmm2"; "%xmm3"; "%xmm4"; "%xmm5"; "%xmm6"; "%xmm7";
"%xmm8"; "%xmm9"; "%xmm10"; "%xmm11";
"%xmm12"; "%xmm13"; "%xmm14"; "%xmm15" |]
let num_register_classes = 2
let register_class r =
match r.typ with
| Val | Int | Addr -> 0
| Float -> 1
let num_available_registers = [| 13; 16 |]
let first_available_register = [| 0; 100 |]
let register_name r =
if r < 100 then int_reg_name.(r) else float_reg_name.(r - 100)
(* Pack registers starting at %rax so as to reduce the number of REX
prefixes and thus improve code density *)
let rotate_registers = false
(* Representation of hard registers by pseudo-registers *)
let hard_int_reg =
let v = Array.make 13 Reg.dummy in
for i = 0 to 12 do v.(i) <- Reg.at_location Int (Reg i) done;
v
let hard_float_reg =
let v = Array.make 16 Reg.dummy in
for i = 0 to 15 do v.(i) <- Reg.at_location Float (Reg (100 + i)) done;
v
let all_phys_regs =
Array.append hard_int_reg hard_float_reg
let phys_reg n =
if n < 100 then hard_int_reg.(n) else hard_float_reg.(n - 100)
let rax = phys_reg 0
let rdx = phys_reg 4
let r10 = phys_reg 10
let r11 = phys_reg 11
let rbp = phys_reg 12
let rxmm15 = phys_reg 115
let destroyed_by_plt_stub =
if not X86_proc.use_plt then [| |] else [| r10; r11 |]
let num_destroyed_by_plt_stub = Array.length destroyed_by_plt_stub
let destroyed_by_plt_stub_set = Reg.set_of_array destroyed_by_plt_stub
let stack_slot slot ty =
Reg.at_location ty (Stack slot)
(* Instruction selection *)
let word_addressed = false
(* Calling conventions *)
let calling_conventions first_int last_int first_float last_float make_stack
arg =
let loc = Array.make (Array.length arg) Reg.dummy in
let int = ref first_int in
let float = ref first_float in
let ofs = ref 0 in
for i = 0 to Array.length arg - 1 do
match arg.(i) with
| Val | Int | Addr as ty ->
if !int <= last_int then begin
loc.(i) <- phys_reg !int;
incr int
end else begin
loc.(i) <- stack_slot (make_stack !ofs) ty;
ofs := !ofs + size_int
end;
assert (not (Reg.Set.mem loc.(i) destroyed_by_plt_stub_set))
| Float ->
if !float <= last_float then begin
loc.(i) <- phys_reg !float;
incr float
end else begin
loc.(i) <- stack_slot (make_stack !ofs) Float;
ofs := !ofs + size_float
end
done;
(loc, Misc.align !ofs 16) (* keep stack 16-aligned *)
let incoming ofs = Incoming ofs
let outgoing ofs = Outgoing ofs
let not_supported _ofs = fatal_error "Proc.loc_results: cannot call"
let loc_arguments arg =
calling_conventions 0 9 100 109 outgoing arg
let loc_parameters arg =
let (loc, _ofs) =
calling_conventions 0 9 100 109 incoming arg
in
loc
let loc_results res =
let (loc, _ofs) = calling_conventions 0 0 100 100 not_supported res in loc
(* C calling conventions under Unix:
first integer args in rdi, rsi, rdx, rcx, r8, r9
first float args in xmm0 ... xmm7
remaining args on stack
return value in rax or xmm0.
C calling conventions under Win64:
first integer args in rcx, rdx, r8, r9
first float args in xmm0 ... xmm3
each integer arg consumes a float reg, and conversely
remaining args on stack
always 32 bytes reserved at bottom of stack.
Return value in rax or xmm0. *)
let loc_external_results res =
let (loc, _ofs) = calling_conventions 0 0 100 100 not_supported res in loc
let unix_loc_external_arguments arg =
calling_conventions 2 7 100 107 outgoing arg
let win64_int_external_arguments =
[| 5 (*rcx*); 4 (*rdx*); 6 (*r8*); 7 (*r9*) |]
let win64_float_external_arguments =
[| 100 (*xmm0*); 101 (*xmm1*); 102 (*xmm2*); 103 (*xmm3*) |]
let win64_loc_external_arguments arg =
let loc = Array.make (Array.length arg) Reg.dummy in
let reg = ref 0
and ofs = ref 32 in
for i = 0 to Array.length arg - 1 do
match arg.(i) with
| Val | Int | Addr as ty ->
if !reg < 4 then begin
loc.(i) <- phys_reg win64_int_external_arguments.(!reg);
incr reg
end else begin
loc.(i) <- stack_slot (Outgoing !ofs) ty;
ofs := !ofs + size_int
end
| Float ->
if !reg < 4 then begin
loc.(i) <- phys_reg win64_float_external_arguments.(!reg);
incr reg
end else begin
loc.(i) <- stack_slot (Outgoing !ofs) Float;
ofs := !ofs + size_float
end
done;
(loc, Misc.align !ofs 16) (* keep stack 16-aligned *)
let loc_external_arguments ty_args =
let arg = Cmm.machtype_of_exttype_list ty_args in
let loc, stack_ofs =
if win64
then win64_loc_external_arguments arg
else unix_loc_external_arguments arg
in
Array.map (fun reg -> [|reg|]) loc, stack_ofs
let loc_exn_bucket = rax
(** See "System V Application Binary Interface, AMD64 Architecture Processor
Supplement" (www.x86-64.org/documentation/abi.pdf) page 57, fig. 3.36. *)
let int_dwarf_reg_numbers =
[| 0; 3; 5; 4; 1; 2; 8; 9; 12; 13; 10; 11; 6 |]
let float_dwarf_reg_numbers =
[| 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32 |]
let dwarf_register_numbers ~reg_class =
match reg_class with
| 0 -> int_dwarf_reg_numbers
| 1 -> float_dwarf_reg_numbers
| _ -> Misc.fatal_errorf "Bad register class %d" reg_class
let stack_ptr_dwarf_register_number = 7
(* Volatile registers: none *)
let regs_are_volatile _rs = false
(* Registers destroyed by operations *)
let destroyed_at_c_call =
if win64 then
(* Win64: rbx, rbp, rsi, rdi, r12-r15, xmm6-xmm15 preserved *)
Array.of_list(List.map phys_reg
[0;4;5;6;7;10;11;
100;101;102;103;104;105])
else
(* Unix: rbp, rbx, r12-r15 preserved *)
Array.of_list(List.map phys_reg
[0;2;3;4;5;6;7;10;11;
100;101;102;103;104;105;106;107;
108;109;110;111;112;113;114;115])
let destroyed_at_alloc =
if X86_proc.use_plt then
destroyed_by_plt_stub
else
[| r11 |]
let destroyed_at_oper = function
Iop(Icall_ind _ | Icall_imm _ | Iextcall { alloc = true; }) ->
all_phys_regs
| Iop(Iextcall { alloc = false; }) -> destroyed_at_c_call
| Iop(Iintop(Idiv | Imod)) | Iop(Iintop_imm((Idiv | Imod), _))
-> [| rax; rdx |]
| Iop(Istore(Single, _, _)) -> [| rxmm15 |]
| Iop(Ialloc _) -> destroyed_at_alloc
| Iop(Iintop(Imulh | Icomp _) | Iintop_imm((Icomp _), _))
-> [| rax |]
| Iswitch(_, _) -> [| rax; rdx |]
| Itrywith _ -> [| r11 |]
| _ ->
if fp then
(* prevent any use of the frame pointer ! *)
[| rbp |]
else
[||]
let destroyed_at_raise = all_phys_regs
let destroyed_at_reloadretaddr = [| |]
(* Maximal register pressure *)
let safe_register_pressure = function
Iextcall _ -> if win64 then if fp then 7 else 8 else 0
| _ -> if fp then 10 else 11
let max_register_pressure = function
Iextcall _ ->
if win64 then
if fp then [| 7; 10 |] else [| 8; 10 |]
else
if fp then [| 3; 0 |] else [| 4; 0 |]
| Iintop(Idiv | Imod) | Iintop_imm((Idiv | Imod), _) ->
if fp then [| 10; 16 |] else [| 11; 16 |]
| Ialloc _ ->
if fp then [| 11 - num_destroyed_by_plt_stub; 16 |]
else [| 12 - num_destroyed_by_plt_stub; 16 |]
| Iintop(Icomp _) | Iintop_imm((Icomp _), _) ->
if fp then [| 11; 16 |] else [| 12; 16 |]
| Istore(Single, _, _) ->
if fp then [| 12; 15 |] else [| 13; 15 |]
| _ -> if fp then [| 12; 16 |] else [| 13; 16 |]
(* Pure operations (without any side effect besides updating their result
registers). *)
let op_is_pure = function
| Icall_ind _ | Icall_imm _ | Itailcall_ind _ | Itailcall_imm _
| Iextcall _ | Istackoffset _ | Istore _ | Ialloc _
| Iintop(Icheckbound _) | Iintop_imm(Icheckbound _, _) -> false
| Ispecific(Ilea _|Isextend32|Izextend32) -> true
| Ispecific _ -> false
| _ -> true
(* Layout of the stack frame *)
let frame_required fd =
fp || fd.fun_contains_calls ||
fd.fun_num_stack_slots.(0) > 0 || fd.fun_num_stack_slots.(1) > 0
let prologue_required fd =
frame_required fd
(* Calling the assembler *)
let assemble_file infile outfile =
X86_proc.assemble_file infile outfile
let init () =
if fp then begin
num_available_registers.(0) <- 12
end else
num_available_registers.(0) <- 13