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VM: after reset_datastack and retainstack clear the stack segment. makes 

it easier to find bad accesses to shadow data
db4
Björn Lindqvist 2015-05-22 16:52:13 +02:00 committed by Doug Coleman
parent 183ec83a6d
commit 8e1f3a0e51
3 changed files with 19 additions and 12 deletions
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10
vm/contexts.cpp
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@ -17,10 +17,12 @@ context::context(cell datastack_size, cell retainstack_size,
void context::reset_datastack() {
datastack = datastack_seg->start - sizeof(cell);
fill_stack_seg(datastack, datastack_seg, 0x11111111);
}
void context::reset_retainstack() {
retainstack = retainstack_seg->start - sizeof(cell);
fill_stack_seg(retainstack, retainstack_seg, 0x22222222);
}
void context::reset_callstack() {
@ -32,6 +34,14 @@ void context::reset_context_objects() {
context_object_count * sizeof(cell));
}
void context::fill_stack_seg(cell top_ptr, segment* seg, cell pattern) {
#ifdef FACTOR_DEBUG
cell clear_start = top_ptr + sizeof(cell);
cell clear_size = seg->end - clear_start;
memset_cell((void*)clear_start, pattern, clear_size);
#endif
}
void context::reset() {
reset_datastack();
reset_retainstack();

1
vm/contexts.hpp
View File

@ -48,6 +48,7 @@ struct context {
void reset_context_objects();
void reset();
void fix_stacks();
void fill_stack_seg(cell top_ptr, segment* seg, cell pattern);
cell peek() { return *(cell*)datastack; }

20
vm/slot_visitor.hpp
View File

@ -381,23 +381,19 @@ void slot_visitor<Fixup>::visit_context(context* ctx) {
stacks. */
visit_callstack(ctx);
cell* ds_ptr = (cell*)ctx->datastack;
cell* rs_ptr = (cell*)ctx->retainstack;
visit_stack_elements(ctx->datastack_seg, ds_ptr);
visit_stack_elements(ctx->retainstack_seg, rs_ptr);
cell ds_ptr = ctx->datastack;
cell rs_ptr = ctx->retainstack;
segment* ds_seg = ctx->datastack_seg;
segment* rs_seg = ctx->retainstack_seg;
visit_stack_elements(ds_seg, (cell*)ds_ptr);
visit_stack_elements(rs_seg, (cell*)rs_ptr);
visit_object_array(ctx->context_objects,
ctx->context_objects + context_object_count);
/* Clear out the space not visited with a known pattern. That makes
it easier to see if uninitialized reads are made. */
#ifdef FACTOR_DEBUG
cell ds_clear_start = (cell)(ds_ptr + 1);
cell ds_clear_size = ctx->datastack_seg->end - ds_clear_start;
memset_cell((void*)ds_clear_start, 0xbaadbaad, ds_clear_size);
cell rs_clear_start = (cell)(rs_ptr + 1);
cell rs_clear_size = ctx->retainstack_seg->end - rs_clear_start;
memset_cell((void*)rs_clear_start, 0xdaabdaab, rs_clear_size);
#endif
ctx->fill_stack_seg(ds_ptr, ds_seg, 0xbaadbadd);
ctx->fill_stack_seg(rs_ptr, rs_seg, 0xdaabdaab);
}
template <typename Fixup> void slot_visitor<Fixup>::visit_contexts() {