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This is broken, but the stack limit feature works. Some debugging needed.

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This commit is contained in:
Simon Brooke 2026-03-13 23:42:57 +00:00
parent 2536e76617
commit d1ce893633
12 changed files with 164 additions and 111 deletions
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66
src/memory/stack.c
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@ -26,6 +26,12 @@
#include "memory/vectorspace.h"
#include "ops/lispops.h"
/**
* @brief If non-zero, maximum depth of stack.
*
*/
uint32_t stack_limit = 0;
/**
* set a register in a stack frame. Alwaye use this to do so,
* because that way we can be sure the inc_ref happens!
@ -68,17 +74,19 @@ struct stack_frame *get_stack_frame( struct cons_pointer pointer ) {
/**
* Make an empty stack frame, and return it.
*
* This function does the actual meat of making the frame.
*
* @param previous the current top-of-stack;
* @param env the environment in which evaluation happens.
* @param depth the depth of the new frame.
* @return the new frame, or NULL if memory is exhausted.
*/
struct cons_pointer make_empty_frame( struct cons_pointer previous ) {
struct cons_pointer in_make_empty_frame( struct cons_pointer previous,
uint32_t depth ) {
debug_print( L"Entering make_empty_frame\n", DEBUG_ALLOC );
struct cons_pointer result =
make_vso( STACKFRAMETV, sizeof( struct stack_frame ) );
debug_dump_object( result, DEBUG_ALLOC );
if ( !nilp( result ) ) {
struct stack_frame *frame = get_stack_frame( result );
/*
@ -86,6 +94,7 @@ struct cons_pointer make_empty_frame( struct cons_pointer previous ) {
*/
frame->previous = previous;
frame->depth = depth;
/*
* clearing the frame with memset would probably be slightly quicker, but
@ -99,7 +108,7 @@ struct cons_pointer make_empty_frame( struct cons_pointer previous ) {
frame->arg[i] = NIL;
}
frame->depth = (nilp(previous)) ? 0 : (get_stack_frame(previous))->depth + 1;
debug_dump_object( result, DEBUG_ALLOC );
}
debug_print( L"Leaving make_empty_frame\n", DEBUG_ALLOC );
debug_dump_object( result, DEBUG_ALLOC );
@ -107,6 +116,37 @@ struct cons_pointer make_empty_frame( struct cons_pointer previous ) {
return result;
}
/**
* @brief Make an empty stack frame, and return it.
*
* This function does the error checking around actual construction.
*
* @param previous the current top-of-stack;
* @param env the environment in which evaluation happens.
* @return the new frame, or NULL if memory is exhausted.
*/
struct cons_pointer make_empty_frame( struct cons_pointer previous ) {
struct cons_pointer result = NIL;
uint32_t depth =
( nilp( previous ) ) ? 0 : ( get_stack_frame( previous ) )->depth + 1;
if ( stack_limit > 0 && stack_limit > depth ) {
result = in_make_empty_frame( previous, depth );
} else {
result =
make_exception( c_string_to_lisp_string
( L"Stack limit exceeded." ), previous );
}
if ( nilp( result ) ) {
/* i.e. out of memory */
result =
make_exception( privileged_string_memory_exhausted, previous );
}
return result;
}
/**
* Allocate a new stack frame with its previous pointer set to this value,
* its arguments set up from these args, evaluated in this env.
@ -121,11 +161,7 @@ struct cons_pointer make_stack_frame( struct cons_pointer previous,
debug_print( L"Entering make_stack_frame\n", DEBUG_STACK );
struct cons_pointer result = make_empty_frame( previous );
if ( nilp( result ) ) {
/* i.e. out of memory */
result =
make_exception( privileged_string_memory_exhausted, previous );
} else {
if ( !exceptionp( result ) ) {
struct stack_frame *frame = get_stack_frame( result );
while ( frame->args < args_in_frame && consp( args ) ) {
@ -191,12 +227,7 @@ struct cons_pointer make_special_frame( struct cons_pointer previous,
struct cons_pointer result = make_empty_frame( previous );
if ( nilp( result ) ) {
/* i.e. out of memory */
result =
make_exception( c_string_to_lisp_string( L"Memory exhausted." ),
previous );
} else {
if ( !exceptionp( result ) ) {
struct stack_frame *frame = get_stack_frame( result );
while ( frame->args < args_in_frame && !nilp( args ) ) {
@ -288,8 +319,7 @@ void dump_frame( URL_FILE *output, struct cons_pointer frame_pointer ) {
if ( frame != NULL ) {
url_fwprintf( output, L"Stack frame %d with %d arguments:\n",
frame->depth;
frame->args );
frame->depth, frame->args );
dump_frame_context( output, frame_pointer, 4 );
for ( int arg = 0; arg < frame->args; arg++ ) {