diff options
Diffstat (limited to 'lib/compiler/src/v3_codegen.erl')
| -rw-r--r-- | lib/compiler/src/v3_codegen.erl | 136 |
1 files changed, 1 insertions, 135 deletions
diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl index e9152ba88f..d7a7778740 100644 --- a/lib/compiler/src/v3_codegen.erl +++ b/lib/compiler/src/v3_codegen.erl @@ -79,13 +79,9 @@ function(#k_fdef{anno=#k{a=Anno},func=Name,arity=Arity, try #k_match{} = Kb, %Assertion. - %% Try to suppress the stack frame unless it is - %% really needed. - Body0 = avoid_stack_frame(Kb), - %% Annotate kernel records with variable usage. Vdb0 = init_vars(As), - {Body,_,Vdb} = body(Body0, 1, Vdb0), + {Body,_,Vdb} = body(Kb, 1, Vdb0), %% Generate the BEAM assembly code. {Asm,EntryLabel,St} = cg_fun(Body, As, Vdb, AtomMod, @@ -98,136 +94,6 @@ function(#k_fdef{anno=#k{a=Anno},func=Name,arity=Arity, erlang:raise(Class, Error, Stack) end. - -%% avoid_stack_frame(Kernel) -> Kernel' -%% If possible, avoid setting up a stack frame. Functions -%% that only do matching, calls to guard BIFs, and tail-recursive -%% calls don't need a stack frame. - -avoid_stack_frame(#k_match{body=Body}=M) -> - try - M#k_match{body=avoid_stack_frame_1(Body)} - catch - impossible -> - M - end. - -avoid_stack_frame_1(#k_alt{first=First0,then=Then0}=Alt) -> - First = avoid_stack_frame_1(First0), - Then = avoid_stack_frame_1(Then0), - Alt#k_alt{first=First,then=Then}; -avoid_stack_frame_1(#k_bif{op=Op}=Bif) -> - case Op of - #k_internal{} -> - %% Most internal BIFs clobber the X registers. - throw(impossible); - _ -> - Bif - end; -avoid_stack_frame_1(#k_break{anno=Anno,args=Args}) -> - #k_guard_break{anno=Anno,args=Args}; -avoid_stack_frame_1(#k_guard_break{}=Break) -> - Break; -avoid_stack_frame_1(#k_enter{}=Enter) -> - %% Tail-recursive calls don't need a stack frame. - Enter; -avoid_stack_frame_1(#k_guard{clauses=Cs0}=Guard) -> - Cs = avoid_stack_frame_list(Cs0), - Guard#k_guard{clauses=Cs}; -avoid_stack_frame_1(#k_guard_clause{guard=G0,body=B0}=C) -> - G = avoid_stack_frame_1(G0), - B = avoid_stack_frame_1(B0), - C#k_guard_clause{guard=G,body=B}; -avoid_stack_frame_1(#k_match{anno=A,vars=Vs,body=B0,ret=Ret}) -> - %% Use #k_guard_match{} instead to avoid saving the X registers - %% to the stack before matching. - B = avoid_stack_frame_1(B0), - #k_guard_match{anno=A,vars=Vs,body=B,ret=Ret}; -avoid_stack_frame_1(#k_guard_match{body=B0}=M) -> - B = avoid_stack_frame_1(B0), - M#k_guard_match{body=B}; -avoid_stack_frame_1(#k_protected{arg=Arg0}=Prot) -> - Arg = avoid_stack_frame_1(Arg0), - Prot#k_protected{arg=Arg}; -avoid_stack_frame_1(#k_put{}=Put) -> - Put; -avoid_stack_frame_1(#k_return{}=Ret) -> - Ret; -avoid_stack_frame_1(#k_select{var=#k_var{anno=Vanno},types=Types0}=Select) -> - case member(reuse_for_context, Vanno) of - false -> - Types = avoid_stack_frame_list(Types0), - Select#k_select{types=Types}; - true -> - %% Including binary patterns that overwrite the register containing - %% the binary with the match context may not be safe. For example, - %% bs_match_SUITE:bin_tail_e/1 with inlining will be rejected by - %% beam_validator. - %% - %% Essentially the following code is produced: - %% - %% bs_match {x,0} => {x,0} - %% ... - %% bs_match {x,0} => {x,1} %% ILLEGAL - %% - %% A bs_match instruction will only accept a match context as the - %% source operand if the source and destination registers are the - %% the same (as in the first bs_match instruction above). - %% The second bs_match instruction is therefore illegal. - %% - %% This situation is avoided if there is a stack frame: - %% - %% move {x,0} => {y,0} - %% bs_match {x,0} => {x,0} - %% ... - %% bs_match {y,0} => {x,1} %% LEGAL - %% - throw(impossible) - end; -avoid_stack_frame_1(#k_seq{arg=#k_call{anno=Anno,op=Op}=Call, - body=#k_break{args=BrArgs0}}=Seq) -> - case Op of - #k_remote{mod=#k_atom{val=Mod}, - name=#k_atom{val=Name}, - arity=Arity} -> - case erl_bifs:is_exit_bif(Mod, Name, Arity) of - false -> - %% Will clobber X registers. Must have a stack frame. - throw(impossible); - true -> - %% The call to this BIF will never return. It is safe - %% to suppress the stack frame. - Bif = #k_bif{anno=Anno, - op=#k_internal{name=guard_error,arity=1}, - args=[Call],ret=[]}, - BrArgs = lists:duplicate(length(BrArgs0), #k_nil{}), - GB = #k_guard_break{anno=#k{us=[],ns=[],a=[]},args=BrArgs}, - Seq#k_seq{arg=Bif,body=GB} - end; - _ -> - %% Will clobber X registers. Must have a stack frame. - throw(impossible) - end; -avoid_stack_frame_1(#k_seq{arg=A0,body=B0}=Seq) -> - A = avoid_stack_frame_1(A0), - B = avoid_stack_frame_1(B0), - Seq#k_seq{arg=A,body=B}; -avoid_stack_frame_1(#k_test{}=Test) -> - Test; -avoid_stack_frame_1(#k_type_clause{values=Values0}=TC) -> - Values = avoid_stack_frame_list(Values0), - TC#k_type_clause{values=Values}; -avoid_stack_frame_1(#k_val_clause{body=B0}=VC) -> - B = avoid_stack_frame_1(B0), - VC#k_val_clause{body=B}; -avoid_stack_frame_1(_Body) -> - throw(impossible). - -avoid_stack_frame_list([H|T]) -> - [avoid_stack_frame_1(H)|avoid_stack_frame_list(T)]; -avoid_stack_frame_list([]) -> []. - - %% This pass creates beam format annotated with variable lifetime %% information. Each thing is given an index and for each variable we %% store the first and last index for its occurrence. The variable |