X-Git-Url: https://git.hcoop.net/bpt/guile.git/blobdiff_plain/c33ecf96a41979be0af1d56a7e12ad7c1196f12b..1f47b6975a4acc980a95ba477b9d90835a7e331c:/libguile/frames.h diff --git a/libguile/frames.h b/libguile/frames.h index 71d5b124d..31f86345f 100644 --- a/libguile/frames.h +++ b/libguile/frames.h @@ -1,4 +1,4 @@ -/* Copyright (C) 2001, 2009, 2010, 2011 Free Software Foundation, Inc. +/* Copyright (C) 2001, 2009, 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc. * * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License @@ -23,108 +23,144 @@ #include "programs.h" -/* - * VM frames - */ +/* Stack frames + ------------ -/* - * It's a little confusing, but there are two representations of frames in this - * file: frame pointers and Scheme objects wrapping those frame pointers. The - * former uses the SCM_FRAME_... macro prefix, the latter SCM_VM_FRAME_.. - * prefix. - * - * The confusing thing is that only Scheme frame objects have functions that use - * them, and they use the scm_frame_.. prefix. Hysterical raisins. - */ + It's a little confusing, but there are two representations of frames + in this file: frame pointers, and Scheme objects wrapping those frame + pointers. The former uses the SCM_FRAME macro prefix, the latter + SCM_VM_FRAME prefix. + + The confusing thing is that only Scheme frame objects have functions + that use them, and they use the lower-case scm_frame prefix. -/* VM Frame Layout - --------------- + Stack frame layout + ------------------ + + /------------------\ + | Local N-1 | <- sp | ... | - | Intermed. val. 0 | <- fp + nargs + nlocs - +------------------+ - | Local variable 1 | - | Local variable 0 | <- fp + nargs - | Argument 1 | - | Argument 0 | <- fp = SCM_FRAME_STACK_ADDRESS (fp) - | Program | <- fp - 1 + | Local 1 | + | Local 0 | <- fp = SCM_FRAME_LOCALS_ADDRESS (fp) +==================+ - | Return address | <- SCM_FRAME_UPPER_ADDRESS (fp) - | MV return address| - | Dynamic link | <- fp - 4 = SCM_FRAME_DATA_ADDRESS (fp) = SCM_FRAME_LOWER_ADDRESS (fp) + | Return address | + | Dynamic link | <- fp - 2 = SCM_FRAME_LOWER_ADDRESS (fp) +==================+ - | | + | | <- fp - 3 = SCM_FRAME_PREVIOUS_SP (fp) + + The calling convention is that a caller prepares a stack frame + consisting of the saved FP and the return address, followed by the + procedure and then the arguments to the call, in order. Thus in the + beginning of a call, the procedure being called is in slot 0, the + first argument is in slot 1, and the SP points to the last argument. + The number of arguments, including the procedure, is thus SP - FP + + 1. + + After ensuring that the correct number of arguments have been passed, + a function will set the stack pointer to point to the last local + slot. This lets a function allocate the temporary space that it + needs once in the beginning of the call, instead of pushing and + popping the stack pointer during the call's extent. + + When a program returns, it returns its values in the slots starting + from local 1, as if the values were arguments to a tail call. We + start from 1 instead of 0 for the convenience of the "values" builtin + function, which can just leave its arguments in place. + + The callee resets the stack pointer to point to the last value. In + this way the caller knows how many values there are: it's the number + of words between the stack pointer and the slot at which the caller + placed the procedure. + + After checking that the number of values returned is appropriate, the + caller shuffles the values around (if needed), and resets the stack + pointer back to its original value from before the call. */ - As can be inferred from this drawing, it is assumed that - `sizeof (SCM *) == sizeof (SCM)', since pointers (the `link' parts) are - assumed to be as long as SCM objects. */ + + /* This structure maps to the contents of a VM stack frame. It can alias a frame directly. */ struct scm_vm_frame { SCM *dynamic_link; - scm_t_uint8 *mv_return_address; - scm_t_uint8 *return_address; - SCM program; - SCM stack[1]; /* Variable-length */ + scm_t_uint32 *return_address; + SCM locals[1]; /* Variable-length */ }; +#define SCM_FRAME_LOWER_ADDRESS(fp) (((SCM *) (fp)) - 2) #define SCM_FRAME_STRUCT(fp) \ - ((struct scm_vm_frame *) SCM_FRAME_DATA_ADDRESS (fp)) - -#define SCM_FRAME_DATA_ADDRESS(fp) (((SCM *) (fp)) - 4) -#define SCM_FRAME_STACK_ADDRESS(fp) (SCM_FRAME_STRUCT (fp)->stack) -#define SCM_FRAME_UPPER_ADDRESS(fp) ((SCM*)&SCM_FRAME_STRUCT (fp)->return_address) -#define SCM_FRAME_LOWER_ADDRESS(fp) ((SCM*)SCM_FRAME_STRUCT (fp)) + ((struct scm_vm_frame *) SCM_FRAME_LOWER_ADDRESS (fp)) +#define SCM_FRAME_LOCALS_ADDRESS(fp) (SCM_FRAME_STRUCT (fp)->locals) -#define SCM_FRAME_BYTE_CAST(x) ((scm_t_uint8 *) SCM_UNPACK (x)) -#define SCM_FRAME_STACK_CAST(x) ((SCM *) SCM_UNPACK (x)) +#define SCM_FRAME_PREVIOUS_SP(fp) (((SCM *) (fp)) - 3) #define SCM_FRAME_RETURN_ADDRESS(fp) \ (SCM_FRAME_STRUCT (fp)->return_address) #define SCM_FRAME_SET_RETURN_ADDRESS(fp, ra) \ SCM_FRAME_STRUCT (fp)->return_address = (ra) -#define SCM_FRAME_MV_RETURN_ADDRESS(fp) \ - (SCM_FRAME_STRUCT (fp)->mv_return_address) -#define SCM_FRAME_SET_MV_RETURN_ADDRESS(fp, mvra) \ - SCM_FRAME_STRUCT (fp)->mv_return_address = (mvra) #define SCM_FRAME_DYNAMIC_LINK(fp) \ (SCM_FRAME_STRUCT (fp)->dynamic_link) #define SCM_FRAME_SET_DYNAMIC_LINK(fp, dl) \ SCM_FRAME_DYNAMIC_LINK (fp) = (dl) -#define SCM_FRAME_VARIABLE(fp,i) \ - (SCM_FRAME_STRUCT (fp)->stack[i]) -#define SCM_FRAME_PROGRAM(fp) \ - (SCM_FRAME_STRUCT (fp)->program) +#define SCM_FRAME_LOCAL(fp,i) \ + (SCM_FRAME_STRUCT (fp)->locals[i]) + +#define SCM_FRAME_NUM_LOCALS(fp, sp) \ + ((sp) + 1 - &SCM_FRAME_LOCAL (fp, 0)) /* * Heap frames */ +#ifdef BUILDING_LIBGUILE + struct scm_frame { - SCM stack_holder; - SCM *fp; - SCM *sp; - scm_t_uint8 *ip; - scm_t_ptrdiff offset; + void *stack_holder; + scm_t_ptrdiff fp_offset; + scm_t_ptrdiff sp_offset; + scm_t_uint32 *ip; }; +enum scm_vm_frame_kind + { + SCM_VM_FRAME_KIND_VM, + SCM_VM_FRAME_KIND_CONT + }; + #define SCM_VM_FRAME_P(x) (SCM_HAS_TYP7 (x, scm_tc7_frame)) -#define SCM_VM_FRAME_DATA(x) ((struct scm_frame*)SCM_CELL_WORD_1 (x)) -#define SCM_VM_FRAME_STACK_HOLDER(f) SCM_VM_FRAME_DATA(f)->stack_holder -#define SCM_VM_FRAME_FP(f) SCM_VM_FRAME_DATA(f)->fp -#define SCM_VM_FRAME_SP(f) SCM_VM_FRAME_DATA(f)->sp -#define SCM_VM_FRAME_IP(f) SCM_VM_FRAME_DATA(f)->ip -#define SCM_VM_FRAME_OFFSET(f) SCM_VM_FRAME_DATA(f)->offset +#define SCM_VM_FRAME_KIND(x) ((enum scm_vm_frame_kind) (SCM_CELL_WORD_0 (x) >> 8)) +#define SCM_VM_FRAME_DATA(x) ((struct scm_frame *)SCM_CELL_WORD_1 (x)) +#define SCM_VM_FRAME_STACK_HOLDER(f) SCM_VM_FRAME_DATA (f)->stack_holder +#define SCM_VM_FRAME_FP_OFFSET(f) SCM_VM_FRAME_DATA (f)->fp_offset +#define SCM_VM_FRAME_SP_OFFSET(f) SCM_VM_FRAME_DATA (f)->sp_offset +#define SCM_VM_FRAME_FP(f) (SCM_VM_FRAME_FP_OFFSET (f) + scm_i_frame_stack_base (f)) +#define SCM_VM_FRAME_SP(f) (SCM_VM_FRAME_SP_OFFSET (f) + scm_i_frame_stack_base (f)) +#define SCM_VM_FRAME_IP(f) SCM_VM_FRAME_DATA (f)->ip +#define SCM_VM_FRAME_OFFSET(f) scm_i_frame_offset (f) #define SCM_VALIDATE_VM_FRAME(p,x) SCM_MAKE_VALIDATE (p, x, VM_FRAME_P) -SCM_API SCM scm_c_make_frame (SCM stack_holder, SCM *fp, SCM *sp, - scm_t_uint8 *ip, scm_t_ptrdiff offset); +SCM_INTERNAL SCM* scm_i_frame_stack_base (SCM frame); +SCM_INTERNAL scm_t_ptrdiff scm_i_frame_offset (SCM frame); + +/* See notes in frames.c before using this. */ +SCM_INTERNAL SCM scm_c_frame_closure (enum scm_vm_frame_kind kind, + const struct scm_frame *frame); + +SCM_INTERNAL SCM scm_c_make_frame (enum scm_vm_frame_kind kind, + const struct scm_frame *frame); + +SCM_INTERNAL int scm_c_frame_previous (enum scm_vm_frame_kind kind, + struct scm_frame *frame); + +#endif + SCM_API SCM scm_frame_p (SCM obj); SCM_API SCM scm_frame_procedure (SCM frame); +SCM_API SCM scm_frame_call_representation (SCM frame); SCM_API SCM scm_frame_arguments (SCM frame); SCM_API SCM scm_frame_source (SCM frame); SCM_API SCM scm_frame_num_locals (SCM frame); @@ -134,7 +170,6 @@ SCM_API SCM scm_frame_address (SCM frame); SCM_API SCM scm_frame_stack_pointer (SCM frame); SCM_API SCM scm_frame_instruction_pointer (SCM frame); SCM_API SCM scm_frame_return_address (SCM frame); -SCM_API SCM scm_frame_mv_return_address (SCM frame); SCM_API SCM scm_frame_dynamic_link (SCM frame); SCM_API SCM scm_frame_previous (SCM frame);