| /* |
| * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers |
| * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. |
| * |
| * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED |
| * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. |
| * |
| * Permission is hereby granted to use or copy this program |
| * for any purpose, provided the above notices are retained on all copies. |
| * Permission to modify the code and to distribute modified code is granted, |
| * provided the above notices are retained, and a notice that the code was |
| * modified is included with the above copyright notice. |
| */ |
| /* Boehm, October 9, 1995 1:06 pm PDT */ |
| # include <stdio.h> |
| # include "gc_priv.h" |
| |
| /* MAX_ROOT_SETS is the maximum number of ranges that can be */ |
| /* registered as static roots. */ |
| # ifdef LARGE_CONFIG |
| # define MAX_ROOT_SETS 4096 |
| # else |
| # ifdef PCR |
| # define MAX_ROOT_SETS 1024 |
| # else |
| # ifdef MSWIN32 |
| # define MAX_ROOT_SETS 512 |
| /* Under NT, we add only written pages, which can result */ |
| /* in many small root sets. */ |
| # else |
| # define MAX_ROOT_SETS 64 |
| # endif |
| # endif |
| # endif |
| |
| # define MAX_EXCLUSIONS (MAX_ROOT_SETS/4) |
| /* Maximum number of segments that can be excluded from root sets. */ |
| |
| /* Data structure for list of root sets. */ |
| /* We keep a hash table, so that we can filter out duplicate additions. */ |
| /* Under Win32, we need to do a better job of filtering overlaps, so */ |
| /* we resort to sequential search, and pay the price. */ |
| struct roots { |
| ptr_t r_start; |
| ptr_t r_end; |
| # ifndef MSWIN32 |
| struct roots * r_next; |
| # endif |
| GC_bool r_tmp; |
| /* Delete before registering new dynamic libraries */ |
| }; |
| |
| static struct roots static_roots[MAX_ROOT_SETS]; |
| |
| static int n_root_sets = 0; |
| |
| /* static_roots[0..n_root_sets) contains the valid root sets. */ |
| |
| # if !defined(NO_DEBUGGING) |
| /* For debugging: */ |
| void GC_print_static_roots() |
| { |
| register int i; |
| size_t total = 0; |
| |
| for (i = 0; i < n_root_sets; i++) { |
| GC_printf2("From 0x%lx to 0x%lx ", |
| (unsigned long) static_roots[i].r_start, |
| (unsigned long) static_roots[i].r_end); |
| if (static_roots[i].r_tmp) { |
| GC_printf0(" (temporary)\n"); |
| } else { |
| GC_printf0("\n"); |
| } |
| total += static_roots[i].r_end - static_roots[i].r_start; |
| } |
| GC_printf1("Total size: %ld\n", (unsigned long) total); |
| if (GC_root_size != total) { |
| GC_printf1("GC_root_size incorrect: %ld!!\n", |
| (unsigned long) GC_root_size); |
| } |
| } |
| # endif /* NO_DEBUGGING */ |
| |
| /* Primarily for debugging support: */ |
| /* Is the address p in one of the registered static */ |
| /* root sections? */ |
| GC_bool GC_is_static_root(p) |
| ptr_t p; |
| { |
| static int last_root_set = 0; |
| register int i; |
| |
| |
| if (p >= static_roots[last_root_set].r_start |
| && p < static_roots[last_root_set].r_end) return(TRUE); |
| for (i = 0; i < n_root_sets; i++) { |
| if (p >= static_roots[i].r_start |
| && p < static_roots[i].r_end) { |
| last_root_set = i; |
| return(TRUE); |
| } |
| } |
| return(FALSE); |
| } |
| |
| #ifndef MSWIN32 |
| # define LOG_RT_SIZE 6 |
| # define RT_SIZE (1 << LOG_RT_SIZE) /* Power of 2, may be != MAX_ROOT_SETS */ |
| |
| static struct roots * root_index[RT_SIZE]; |
| /* Hash table header. Used only to check whether a range is */ |
| /* already present. */ |
| |
| static int rt_hash(addr) |
| char * addr; |
| { |
| word result = (word) addr; |
| # if CPP_WORDSZ > 8*LOG_RT_SIZE |
| result ^= result >> 8*LOG_RT_SIZE; |
| # endif |
| # if CPP_WORDSZ > 4*LOG_RT_SIZE |
| result ^= result >> 4*LOG_RT_SIZE; |
| # endif |
| result ^= result >> 2*LOG_RT_SIZE; |
| result ^= result >> LOG_RT_SIZE; |
| result &= (RT_SIZE-1); |
| return(result); |
| } |
| |
| /* Is a range starting at b already in the table? If so return a */ |
| /* pointer to it, else NIL. */ |
| struct roots * GC_roots_present(b) |
| char *b; |
| { |
| register int h = rt_hash(b); |
| register struct roots *p = root_index[h]; |
| |
| while (p != 0) { |
| if (p -> r_start == (ptr_t)b) return(p); |
| p = p -> r_next; |
| } |
| return(FALSE); |
| } |
| |
| /* Add the given root structure to the index. */ |
| static void add_roots_to_index(p) |
| struct roots *p; |
| { |
| register int h = rt_hash(p -> r_start); |
| |
| p -> r_next = root_index[h]; |
| root_index[h] = p; |
| } |
| |
| # else /* MSWIN32 */ |
| |
| # define add_roots_to_index(p) |
| |
| # endif |
| |
| |
| |
| |
| word GC_root_size = 0; |
| |
| void GC_add_roots(b, e) |
| char * b; char * e; |
| { |
| DCL_LOCK_STATE; |
| |
| DISABLE_SIGNALS(); |
| LOCK(); |
| GC_add_roots_inner(b, e, FALSE); |
| UNLOCK(); |
| ENABLE_SIGNALS(); |
| } |
| |
| |
| /* Add [b,e) to the root set. Adding the same interval a second time */ |
| /* is a moderately fast noop, and hence benign. We do not handle */ |
| /* different but overlapping intervals efficiently. (We do handle */ |
| /* them correctly.) */ |
| /* Tmp specifies that the interval may be deleted before */ |
| /* reregistering dynamic libraries. */ |
| void GC_add_roots_inner(b, e, tmp) |
| char * b; char * e; |
| GC_bool tmp; |
| { |
| struct roots * old; |
| |
| # ifdef MSWIN32 |
| /* Spend the time to ensure that there are no overlapping */ |
| /* or adjacent intervals. */ |
| /* This could be done faster with e.g. a */ |
| /* balanced tree. But the execution time here is */ |
| /* virtually guaranteed to be dominated by the time it */ |
| /* takes to scan the roots. */ |
| { |
| register int i; |
| |
| for (i = 0; i < n_root_sets; i++) { |
| old = static_roots + i; |
| if ((ptr_t)b <= old -> r_end && (ptr_t)e >= old -> r_start) { |
| if ((ptr_t)b < old -> r_start) { |
| old -> r_start = (ptr_t)b; |
| GC_root_size += (old -> r_start - (ptr_t)b); |
| } |
| if ((ptr_t)e > old -> r_end) { |
| old -> r_end = (ptr_t)e; |
| GC_root_size += ((ptr_t)e - old -> r_end); |
| } |
| old -> r_tmp &= tmp; |
| break; |
| } |
| } |
| if (i < n_root_sets) { |
| /* merge other overlapping intervals */ |
| struct roots *other; |
| |
| for (i++; i < n_root_sets; i++) { |
| other = static_roots + i; |
| b = (char *)(other -> r_start); |
| e = (char *)(other -> r_end); |
| if ((ptr_t)b <= old -> r_end && (ptr_t)e >= old -> r_start) { |
| if ((ptr_t)b < old -> r_start) { |
| old -> r_start = (ptr_t)b; |
| GC_root_size += (old -> r_start - (ptr_t)b); |
| } |
| if ((ptr_t)e > old -> r_end) { |
| old -> r_end = (ptr_t)e; |
| GC_root_size += ((ptr_t)e - old -> r_end); |
| } |
| old -> r_tmp &= other -> r_tmp; |
| /* Delete this entry. */ |
| GC_root_size -= (other -> r_end - other -> r_start); |
| other -> r_start = static_roots[n_root_sets-1].r_start; |
| other -> r_end = static_roots[n_root_sets-1].r_end; |
| n_root_sets--; |
| } |
| } |
| return; |
| } |
| } |
| # else |
| old = GC_roots_present(b); |
| if (old != 0) { |
| if ((ptr_t)e <= old -> r_end) /* already there */ return; |
| /* else extend */ |
| GC_root_size += (ptr_t)e - old -> r_end; |
| old -> r_end = (ptr_t)e; |
| return; |
| } |
| # endif |
| if (n_root_sets == MAX_ROOT_SETS) { |
| ABORT("Too many root sets\n"); |
| } |
| static_roots[n_root_sets].r_start = (ptr_t)b; |
| static_roots[n_root_sets].r_end = (ptr_t)e; |
| static_roots[n_root_sets].r_tmp = tmp; |
| # ifndef MSWIN32 |
| static_roots[n_root_sets].r_next = 0; |
| # endif |
| add_roots_to_index(static_roots + n_root_sets); |
| GC_root_size += (ptr_t)e - (ptr_t)b; |
| n_root_sets++; |
| } |
| |
| void GC_clear_roots GC_PROTO((void)) |
| { |
| DCL_LOCK_STATE; |
| |
| DISABLE_SIGNALS(); |
| LOCK(); |
| n_root_sets = 0; |
| GC_root_size = 0; |
| # ifndef MSWIN32 |
| { |
| register int i; |
| |
| for (i = 0; i < RT_SIZE; i++) root_index[i] = 0; |
| } |
| # endif |
| UNLOCK(); |
| ENABLE_SIGNALS(); |
| } |
| |
| /* Internal use only; lock held. */ |
| void GC_remove_tmp_roots() |
| { |
| register int i; |
| |
| for (i = 0; i < n_root_sets; ) { |
| if (static_roots[i].r_tmp) { |
| GC_root_size -= (static_roots[i].r_end - static_roots[i].r_start); |
| static_roots[i].r_start = static_roots[n_root_sets-1].r_start; |
| static_roots[i].r_end = static_roots[n_root_sets-1].r_end; |
| static_roots[i].r_tmp = static_roots[n_root_sets-1].r_tmp; |
| n_root_sets--; |
| } else { |
| i++; |
| } |
| } |
| # ifndef MSWIN32 |
| { |
| register int i; |
| |
| for (i = 0; i < RT_SIZE; i++) root_index[i] = 0; |
| for (i = 0; i < n_root_sets; i++) add_roots_to_index(static_roots + i); |
| } |
| # endif |
| |
| } |
| |
| ptr_t GC_approx_sp() |
| { |
| word dummy; |
| |
| return((ptr_t)(&dummy)); |
| } |
| |
| /* |
| * Data structure for excluded static roots. |
| */ |
| struct exclusion { |
| ptr_t e_start; |
| ptr_t e_end; |
| }; |
| |
| struct exclusion excl_table[MAX_EXCLUSIONS]; |
| /* Array of exclusions, ascending */ |
| /* address order. */ |
| size_t excl_table_entries = 0; /* Number of entries in use. */ |
| |
| /* Return the first exclusion range that includes an address >= start_addr */ |
| /* Assumes the exclusion table contains at least one entry (namely the */ |
| /* GC data structures). */ |
| struct exclusion * GC_next_exclusion(start_addr) |
| ptr_t start_addr; |
| { |
| size_t low = 0; |
| size_t high = excl_table_entries - 1; |
| size_t mid; |
| |
| while (high > low) { |
| mid = (low + high) >> 1; |
| /* low <= mid < high */ |
| if ((word) excl_table[mid].e_end <= (word) start_addr) { |
| low = mid + 1; |
| } else { |
| high = mid; |
| } |
| } |
| if ((word) excl_table[low].e_end <= (word) start_addr) return 0; |
| return excl_table + low; |
| } |
| |
| void GC_exclude_static_roots(start, finish) |
| GC_PTR start; |
| GC_PTR finish; |
| { |
| struct exclusion * next; |
| size_t next_index, i; |
| |
| if (0 == excl_table_entries) { |
| next = 0; |
| } else { |
| next = GC_next_exclusion(start); |
| } |
| if (0 != next) { |
| if ((word)(next -> e_start) < (word) finish) { |
| /* incomplete error check. */ |
| ABORT("exclusion ranges overlap"); |
| } |
| if ((word)(next -> e_start) == (word) finish) { |
| /* extend old range backwards */ |
| next -> e_start = (ptr_t)start; |
| return; |
| } |
| next_index = next - excl_table; |
| for (i = excl_table_entries; i > next_index; --i) { |
| excl_table[i] = excl_table[i-1]; |
| } |
| } else { |
| next_index = excl_table_entries; |
| } |
| if (excl_table_entries == MAX_EXCLUSIONS) ABORT("Too many exclusions"); |
| excl_table[next_index].e_start = (ptr_t)start; |
| excl_table[next_index].e_end = (ptr_t)finish; |
| ++excl_table_entries; |
| } |
| |
| /* Invoke push_conditional on ranges that are not excluded. */ |
| void GC_push_conditional_with_exclusions(bottom, top, all) |
| ptr_t bottom; |
| ptr_t top; |
| int all; |
| { |
| struct exclusion * next; |
| ptr_t excl_start; |
| |
| while (bottom < top) { |
| next = GC_next_exclusion(bottom); |
| if (0 == next || (excl_start = next -> e_start) >= top) { |
| GC_push_conditional(bottom, top, all); |
| return; |
| } |
| if (excl_start > bottom) GC_push_conditional(bottom, excl_start, all); |
| bottom = next -> e_end; |
| } |
| } |
| |
| /* |
| * Call the mark routines (GC_tl_push for a single pointer, GC_push_conditional |
| * on groups of pointers) on every top level accessible pointer. |
| * If all is FALSE, arrange to push only possibly altered values. |
| */ |
| |
| void GC_push_roots(all) |
| GC_bool all; |
| { |
| register int i; |
| |
| /* |
| * push registers - i.e., call GC_push_one(r) for each |
| * register contents r. |
| */ |
| GC_push_regs(); /* usually defined in machine_dep.c */ |
| |
| /* |
| * Next push static data. This must happen early on, since it's |
| * not robust against mark stack overflow. |
| */ |
| /* Reregister dynamic libraries, in case one got added. */ |
| # if (defined(DYNAMIC_LOADING) || defined(MSWIN32) || defined(PCR)) \ |
| && !defined(SRC_M3) |
| GC_remove_tmp_roots(); |
| GC_register_dynamic_libraries(); |
| # endif |
| /* Mark everything in static data areas */ |
| for (i = 0; i < n_root_sets; i++) { |
| GC_push_conditional_with_exclusions( |
| static_roots[i].r_start, |
| static_roots[i].r_end, all); |
| } |
| |
| /* |
| * Now traverse stacks. |
| */ |
| # ifndef THREADS |
| /* Mark everything on the stack. */ |
| # ifdef STACK_GROWS_DOWN |
| GC_push_all_stack( GC_approx_sp(), GC_stackbottom ); |
| # else |
| GC_push_all_stack( GC_stackbottom, GC_approx_sp() ); |
| # endif |
| # endif |
| if (GC_push_other_roots != 0) (*GC_push_other_roots)(); |
| /* In the threads case, this also pushes thread stacks. */ |
| } |
| |
