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[sledge] Revise llvm to llair translation to avoid code duplication

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Summary:
In some cases inlining pure expressions into their use sites causes
code blowup. This diff changes the frontend to inline expressions only
if there is a single use, and otherwise adds a move instruction.

Reviewed By: ngorogiannis

Differential Revision: D17071770

fbshipit-source-id: d866a0622
master
Josh Berdine 5 years ago committed by Facebook Github Bot
parent 6e1adf4d1d
commit 13fb57ec62
1 changed files with 124 additions and 101 deletions
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225
sledge/src/llair/frontend.ml
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@ -297,11 +297,21 @@ let xlate_name_opt : Llvm.llvalue -> Var.t option =
| Void -> None
| _ -> Some (xlate_name instr)
let memo_value : (Llvm.llvalue, Exp.t) Hashtbl.t = Hashtbl.Poly.create ()
let memo_value : (bool * Llvm.llvalue, Exp.t) Hashtbl.t =
Hashtbl.Poly.create ()
let memo_global : (Llvm.llvalue, Global.t) Hashtbl.t =
Hashtbl.Poly.create ()
let should_inline : Llvm.llvalue -> bool =
fun llv ->
match Llvm.use_begin llv with
| Some use -> (
match Llvm.use_succ use with
| Some _ -> false (* do not inline if >= 2 uses *)
| None -> true )
| None -> true
module Llvalue = struct
type t = Llvm.llvalue
@ -339,7 +349,7 @@ let rec xlate_intrinsic_exp : string -> (x -> Llvm.llvalue -> Exp.t) option
xlate_llvm_eh_typeid_for x src arg )
| _ -> None
and xlate_value : x -> Llvm.llvalue -> Exp.t =
and xlate_value ?(inline = false) : x -> Llvm.llvalue -> Exp.t =
fun x llv ->
let xlate_value_ llv =
match Llvm.classify_value llv with
@ -347,8 +357,8 @@ and xlate_value : x -> Llvm.llvalue -> Exp.t =
let func = Llvm.operand llv (Llvm.num_arg_operands llv) in
let fname = Llvm.value_name func in
match xlate_intrinsic_exp fname with
| Some intrinsic -> intrinsic x llv
| None -> Exp.var (xlate_name llv) )
| Some intrinsic when inline || should_inline llv -> intrinsic x llv
| _ -> Exp.var (xlate_name llv) )
| Instruction (Invoke | Alloca | Load | PHI | LandingPad | VAArg)
|Argument ->
Exp.var (xlate_name llv)
@ -396,8 +406,9 @@ and xlate_value : x -> Llvm.llvalue -> Exp.t =
| Add | FAdd | Sub | FSub | Mul | FMul | UDiv | SDiv | FDiv | URem
| SRem | FRem | Shl | LShr | AShr | And | Or | Xor | ICmp | FCmp
| Select | GetElementPtr | ExtractElement | InsertElement
| ExtractValue | InsertValue | ShuffleVector ) as opcode ) ->
xlate_opcode x llv opcode
| ShuffleVector | ExtractValue | InsertValue ) as opcode ) ->
if inline || should_inline llv then xlate_opcode x llv opcode
else Exp.var (xlate_name llv)
| ConstantExpr -> xlate_opcode x llv (Llvm.constexpr_opcode llv)
| GlobalIFunc -> todo "ifuncs: %a" pp_llvalue llv ()
| Instruction (CatchPad | CleanupPad | CatchSwitch) ->
@ -409,7 +420,7 @@ and xlate_value : x -> Llvm.llvalue -> Exp.t =
|NullValue | BasicBlock | InlineAsm | MDNode | MDString ->
fail "xlate_value: %a" pp_llvalue llv ()
in
Hashtbl.find_or_add memo_value llv ~default:(fun () ->
Hashtbl.find_or_add memo_value (inline, llv) ~default:(fun () ->
[%Trace.call fun {pf} -> pf "%a" pp_llvalue llv]
;
xlate_value_ llv
@ -780,6 +791,14 @@ let xlate_instr :
in
let name = find_name instr in
let loc = find_loc instr in
let inline_or_move xlate =
if should_inline instr then nop ()
else
let reg = xlate_name instr in
let exp = xlate instr in
let reg_exps = Vector.of_array [|(reg, exp)|] in
emit_inst (Llair.Inst.move ~reg_exps ~loc)
in
let opcode = Llvm.instr_opcode instr in
match opcode with
| Load ->
@ -837,101 +856,105 @@ let xlate_instr :
emit_inst (Llair.Inst.nondet ~reg ~msg:fname ~loc)
in
(* intrinsics *)
match String.split fname ~on:'.' with
| _ when Option.is_some (xlate_intrinsic_exp fname) -> nop ()
| ["__llair_throw"] ->
let exc = xlate_value x (Llvm.operand instr 0) in
emit_term ~prefix:(pop loc) (Llair.Term.throw ~exc ~loc)
| ["__llair_alloc" (* void* __llair_alloc(unsigned size) *)] ->
let reg = xlate_name instr in
let num_operand = Llvm.operand instr 0 in
let num =
Exp.convert ~dst:Typ.siz
(xlate_value x num_operand)
~src:(xlate_type x (Llvm.type_of num_operand))
in
let len = Exp.integer (Z.of_int 1) Typ.siz in
emit_inst (Llair.Inst.alloc ~reg ~num ~len ~loc)
| ["_Znwm" (* operator new(size_t num) *)]
|[ "_ZnwmSt11align_val_t"
(* operator new(unsigned long, std::align_val_t) *) ] ->
let reg = xlate_name instr in
let num = xlate_value x (Llvm.operand instr 0) in
let llt = Llvm.type_of instr in
let len = Exp.integer (Z.of_int (size_of x llt)) Typ.siz in
emit_inst (Llair.Inst.alloc ~reg ~num ~len ~loc)
| ["_ZdlPv" (* operator delete(void* ptr) *)]
|[ "_ZdlPvSt11align_val_t"
(* operator delete(void* ptr, std::align_val_t) *) ]
|[ "_ZdlPvmSt11align_val_t"
(* operator delete(void* ptr, unsigned long, std::align_val_t) *)
]
|["free" (* void free(void* ptr) *)] ->
let ptr = xlate_value x (Llvm.operand instr 0) in
emit_inst (Llair.Inst.free ~ptr ~loc)
| "llvm" :: "memset" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let byt = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memset ~dst ~byt ~len ~loc)
| "llvm" :: "memcpy" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let src = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memcpy ~dst ~src ~len ~loc)
| "llvm" :: "memmove" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let src = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memmov ~dst ~src ~len ~loc)
| ["abort"] | ["llvm"; "trap"] -> emit_inst (Llair.Inst.abort ~loc)
(* dropped / handled elsewhere *)
| ["llvm"; "dbg"; ("declare" | "value")]
|"llvm" :: ("lifetime" | "invariant") :: ("start" | "end") :: _ ->
nop ()
(* unimplemented *)
| ["llvm"; ("stacksave" | "stackrestore")] ->
skip "dynamic stack deallocation"
| "llvm" :: "coro" :: _ -> todo "coroutines:@ %a" pp_llvalue instr ()
| "llvm" :: "experimental" :: "gc" :: "statepoint" :: _ ->
todo "statepoints:@ %a" pp_llvalue instr ()
| ["llvm"; ("va_start" | "va_copy" | "va_end")] ->
skip "variadic function intrinsic"
| "llvm" :: _ -> skip "intrinsic"
| _ when Poly.equal (Llvm.classify_value llfunc) InlineAsm ->
skip "inline asm"
(* general function call that may not throw *)
| _ ->
let func = xlate_func_name x llfunc in
let typ = xlate_type x (Llvm.type_of llfunc) in
let lbl = name ^ ".ret" in
let call =
let args =
let num_args =
if not (Llvm.is_var_arg (Llvm.element_type lltyp)) then
Llvm.num_arg_operands instr
else
let fname = Llvm.value_name llfunc in
( match Hash_set.strict_add ignored_callees fname with
| Ok () when not (Llvm.is_declaration llfunc) ->
warn
"ignoring variable arguments to variadic function: \
%a"
Exp.pp func ()
| _ -> () ) ;
Array.length (Llvm.param_types (Llvm.element_type lltyp))
match xlate_intrinsic_exp fname with
| Some intrinsic -> inline_or_move (intrinsic x)
| None -> (
match String.split fname ~on:'.' with
| ["__llair_throw"] ->
let exc = xlate_value x (Llvm.operand instr 0) in
emit_term ~prefix:(pop loc) (Llair.Term.throw ~exc ~loc)
| ["__llair_alloc" (* void* __llair_alloc(unsigned size) *)] ->
let reg = xlate_name instr in
let num_operand = Llvm.operand instr 0 in
let num =
Exp.convert ~dst:Typ.siz
(xlate_value x num_operand)
~src:(xlate_type x (Llvm.type_of num_operand))
in
let len = Exp.integer (Z.of_int 1) Typ.siz in
emit_inst (Llair.Inst.alloc ~reg ~num ~len ~loc)
| ["_Znwm" (* operator new(size_t num) *)]
|[ "_ZnwmSt11align_val_t"
(* operator new(unsigned long, std::align_val_t) *) ] ->
let reg = xlate_name instr in
let num = xlate_value x (Llvm.operand instr 0) in
let llt = Llvm.type_of instr in
let len = Exp.integer (Z.of_int (size_of x llt)) Typ.siz in
emit_inst (Llair.Inst.alloc ~reg ~num ~len ~loc)
| ["_ZdlPv" (* operator delete(void* ptr) *)]
|[ "_ZdlPvSt11align_val_t"
(* operator delete(void* ptr, std::align_val_t) *) ]
|[ "_ZdlPvmSt11align_val_t"
(* operator delete(void* ptr, unsigned long, std::align_val_t) *)
]
|["free" (* void free(void* ptr) *)] ->
let ptr = xlate_value x (Llvm.operand instr 0) in
emit_inst (Llair.Inst.free ~ptr ~loc)
| "llvm" :: "memset" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let byt = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memset ~dst ~byt ~len ~loc)
| "llvm" :: "memcpy" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let src = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memcpy ~dst ~src ~len ~loc)
| "llvm" :: "memmove" :: _ ->
let dst = xlate_value x (Llvm.operand instr 0) in
let src = xlate_value x (Llvm.operand instr 1) in
let len = xlate_value x (Llvm.operand instr 2) in
emit_inst (Llair.Inst.memmov ~dst ~src ~len ~loc)
| ["abort"] | ["llvm"; "trap"] -> emit_inst (Llair.Inst.abort ~loc)
(* dropped / handled elsewhere *)
| ["llvm"; "dbg"; ("declare" | "value")]
|"llvm" :: ("lifetime" | "invariant") :: ("start" | "end") :: _ ->
nop ()
(* unimplemented *)
| ["llvm"; ("stacksave" | "stackrestore")] ->
skip "dynamic stack deallocation"
| "llvm" :: "coro" :: _ ->
todo "coroutines:@ %a" pp_llvalue instr ()
| "llvm" :: "experimental" :: "gc" :: "statepoint" :: _ ->
todo "statepoints:@ %a" pp_llvalue instr ()
| ["llvm"; ("va_start" | "va_copy" | "va_end")] ->
skip "variadic function intrinsic"
| "llvm" :: _ -> skip "intrinsic"
| _ when Poly.equal (Llvm.classify_value llfunc) InlineAsm ->
skip "inline asm"
(* general function call that may not throw *)
| _ ->
let func = xlate_func_name x llfunc in
let typ = xlate_type x (Llvm.type_of llfunc) in
let lbl = name ^ ".ret" in
let call =
let args =
let num_args =
if not (Llvm.is_var_arg (Llvm.element_type lltyp)) then
Llvm.num_arg_operands instr
else
let fname = Llvm.value_name llfunc in
( match Hash_set.strict_add ignored_callees fname with
| Ok () when not (Llvm.is_declaration llfunc) ->
warn
"ignoring variable arguments to variadic \
function: %a"
Exp.pp func ()
| _ -> () ) ;
Array.length
(Llvm.param_types (Llvm.element_type lltyp))
in
List.rev_init num_args ~f:(fun i ->
xlate_value x (Llvm.operand instr i) )
in
List.rev_init num_args ~f:(fun i ->
xlate_value x (Llvm.operand instr i) )
let areturn = xlate_name_opt instr in
let return = Llair.Jump.mk lbl in
Llair.Term.call ~func ~typ ~args ~areturn ~return ~throw:None
~loc
in
let areturn = xlate_name_opt instr in
let return = Llair.Jump.mk lbl in
Llair.Term.call ~func ~typ ~args ~areturn ~return ~throw:None
~loc
in
continue (fun (insts, term) ->
let cmnd = Vector.of_list insts in
([], call, [Llair.Block.mk ~lbl ~cmnd ~term]) ) )
continue (fun (insts, term) ->
let cmnd = Vector.of_list insts in
([], call, [Llair.Block.mk ~lbl ~cmnd ~term]) ) ) )
| Invoke -> (
let llfunc = Llvm.operand instr (Llvm.num_operands instr - 3) in
let lltyp = Llvm.type_of llfunc in
@ -1162,7 +1185,7 @@ let xlate_instr :
|Shl | LShr | AShr | And | Or | Xor | ICmp | FCmp | Select
|GetElementPtr | ExtractElement | InsertElement | ShuffleVector
|ExtractValue | InsertValue ->
nop ()
inline_or_move (xlate_value ~inline:true x)
| VAArg ->
let reg = xlate_name_opt instr in
warn "variadic function argument: %a" Loc.pp loc () ;

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