diff options
Diffstat (limited to 'lib/compiler')
| -rw-r--r-- | lib/compiler/src/beam_validator.erl | 49 |
1 files changed, 24 insertions, 25 deletions
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl index 5e01855ca1..8064912aac 100644 --- a/lib/compiler/src/beam_validator.erl +++ b/lib/compiler/src/beam_validator.erl @@ -111,11 +111,11 @@ validate_0(Module, [{function,Name,Ar,Entry,Code}|Fs], Ft) -> erlang:raise(Class, Error, Stack) end. -%% This is a psuedo-type used to track tuples under construction, match context -%% positions, and so on. It is not a part of the beam_types type lattice and -%% should not leak outside this module. -record(t_abstract, {kind}). +%% The types are the same as in 'beam_types.hrl', with the addition of +%% #t_abstract{} that describes tuples under construction, match context +%% positions, and so on. -type validator_type() :: #t_abstract{} | type(). -record(value_ref, {id :: index()}). @@ -131,6 +131,24 @@ validate_0(Module, [{function,Name,Ar,Entry,Code}|Fs], Ft) -> {literal, term()} | nil. +%% Register tags describe the state of the register rather than the value they +%% contain (if any). +%% +%% initialized The register has been initialized with some valid term +%% so that it is safe to pass to the garbage collector. +%% NOT safe to use in any other way (will not crash the +%% emulator, but clearly points to a bug in the compiler). +%% +%% uninitialized The register contains any old garbage and can not be +%% passed to the garbage collector. +%% +%% {catchtag,[Lbl]} A special term used within a catch. Must only be used +%% by the catch instructions; NOT safe to use in other +%% instructions. +%% +%% {trytag,[Lbl]} A special term used within a try block. Must only be +%% used by the catch instructions; NOT safe to use in other +%% instructions. -type tag() :: initialized | uninitialized | {catchtag, [label()]} | @@ -1903,30 +1921,11 @@ is_literal({integer,I}) when is_integer(I) -> true; is_literal({literal,_L}) -> true; is_literal(_) -> false. -%% The possible types. -%% -%% First non-term types: -%% -%% initialized Only for Y registers. Means that the Y register -%% has been initialized with some valid term so that -%% it is safe to pass to the garbage collector. -%% NOT safe to use in any other way (will not crash the -%% emulator, but clearly points to a bug in the compiler). -%% -%% {catchtag,[Lbl]} A special term used within a catch. Must only be used -%% by the catch instructions; NOT safe to use in other -%% instructions. -%% -%% {trytag,[Lbl]} A special term used within a try block. Must only be -%% used by the catch instructions; NOT safe to use in other -%% instructions. -%% -%% #t_bs_context{} A match context for bit syntax matching. We do allow -%% it to moved/to from stack, but otherwise it must only -%% be accessed by bit syntax matching instructions. - %% These are just wrappers around their equivalents in beam_types, which %% handle the validator-specific #t_abstract{} type. +%% +%% The funny-looking abstract types produced here are intended to provoke +%% errors on actual use; they do no harm just lying around. join(Same, Same) -> Same; join(#t_abstract{}=A, B) -> #t_abstract{kind={join, A, B}}; |