src/runtime/alloc.c

   1 /*
   2  * allocation routines for C code.  For allocation done by Lisp look
   3  * instead at src/compiler/target/alloc.lisp and .../macros.lisp
   4  */
   5
   6 /*
   7  * This software is part of the SBCL system. See the README file for
   8  * more information.
   9  *
  10  * This software is derived from the CMU CL system, which was
  11  * written at Carnegie Mellon University and released into the
  12  * public domain. The software is in the public domain and is
  13  * provided with absolutely no warranty. See the COPYING and CREDITS
  14  * files for more information.
  15  */
  16
  17 #include <stdio.h>
  18 #include <string.h>
  19
  20 #include "sbcl.h"
  21 #include "runtime.h"
  22 #include "os.h"
  23 #include "alloc.h"
  24 #include "globals.h"
  25 #include "gc.h"
  26 #include "thread.h"
  27 #include "pseudo-atomic.h"
  28 #include "genesis/vector.h"
  29 #include "genesis/cons.h"
  30 #include "genesis/bignum.h"
  31 #include "genesis/sap.h"
  32 #include "genesis/code.h"
  33
  34 #define ALIGNED_SIZE(n) ((n) + LOWTAG_MASK) & ~LOWTAG_MASK
  35
  36 #ifdef LISP_FEATURE_GENCGC
  37 static lispobj *
  38 pa_alloc(int bytes, int page_type_flag)
  39 {
  40     lispobj *result;
  41     struct thread *th = arch_os_get_current_thread();
  42
  43     /* SIG_STOP_FOR_GC must be unblocked: else two threads racing here
  44      * may deadlock: one will wait on the GC lock, and the other
  45      * cannot stop the first one... */
  46     check_gc_signals_unblocked_or_lose(0);
  47
  48     /* FIXME: OOAO violation: see arch_pseudo_* */
  49     set_pseudo_atomic_atomic(th);
  50     result = general_alloc(bytes, page_type_flag);
  51 #if 0
  52     /* See how the runtime deals with GC being triggerred. */
  53     if ((SymbolValue(GC_PENDING,th) == NIL) &&
  54         (SymbolValue(GC_INHIBIT,th) == NIL) &&
  55         (random() < RAND_MAX/100)) {
  56         SetSymbolValue(GC_PENDING,T,th);
  57         set_pseudo_atomic_interrupted(th);
  58         maybe_save_gc_mask_and_block_deferrables(NULL);
  59     }
  60 #endif
  61     clear_pseudo_atomic_atomic(th);
  62
  63     if (get_pseudo_atomic_interrupted(th)) {
  64         /* WARNING KLUDGE FIXME: pa_alloc() is not pseudo-atomic on
  65          * anything but x86[-64]. maybe_defer_handler doesn't defer
  66          * interrupts if foreign_function_call_active
  67          *
  68          * If the C stack is not scavenged during GC, result needs to
  69          * be protected against not being referred to by any roots, so
  70          * we push it onto the lisp control stack, and read it back
  71          * off after any potential GC has finished */
  72 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  73 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
  74 #error "!C_STACK_IS_CONTROL_STACK and STACK_GROWS_DOWNWARD_NOT_UPWARD is not supported"
  75 #endif
  76         *current_control_stack_pointer = (lispobj) result;
  77         current_control_stack_pointer += 1;
  78 #endif
  79         do_pending_interrupt();
  80 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  81         current_control_stack_pointer -= 1;
  82         result = (lispobj *) *current_control_stack_pointer;
  83 #endif
  84     }
  85     return result;
  86 }
  87 #else
  88 static lispobj *
  89 pa_alloc(int bytes, int page_type_flag)
  90 {
  91     lispobj *result;
  92
  93     /* This is not pseudo atomic at all, but is called only from
  94      * interrupt safe places like interrupt handlers. MG -
  95      * 2005-08-09 */
  96     check_deferrables_blocked_or_lose(0);
  97
  98     result = dynamic_space_free_pointer;
  99
 100     /* Align up to next dual word boundary. */
 101     bytes = ALIGNED_SIZE(bytes);
 102
 103     dynamic_space_free_pointer = (lispobj *)((char *)result + bytes);
 104
 105     if (current_auto_gc_trigger
 106         && dynamic_space_free_pointer > current_auto_gc_trigger) {
 107         clear_auto_gc_trigger();
 108         set_auto_gc_trigger((char *)dynamic_space_free_pointer
 109                             - (char *)current_dynamic_space);
 110     }
 111     return result;
 112 }
 113 #endif
 114
 115 static lispobj *
 116 alloc_unboxed(int type, int words)
 117 {
 118     lispobj *result;
 119
 120     result = pa_alloc(ALIGNED_SIZE((1 + words) * sizeof(lispobj)),
 121                       UNBOXED_PAGE_FLAG);
 122     *result = (lispobj) (words << N_WIDETAG_BITS) | type;
 123     return result;
 124 }
 125
 126 static lispobj
 127 alloc_vector(int type, int length, int size, int page_type_flag)
 128 {
 129     struct vector *result;
 130
 131     result = (struct vector *)
 132         pa_alloc(ALIGNED_SIZE((2 + (length*size + 31) / 32) * sizeof(lispobj)),
 133                  page_type_flag);
 134
 135     result->header = type;
 136     result->length = make_fixnum(length);
 137
 138     return make_lispobj(result,OTHER_POINTER_LOWTAG);
 139 }
 140
 141 lispobj
 142 alloc_cons(lispobj car, lispobj cdr)
 143 {
 144     struct cons *ptr =
 145         (struct cons *)pa_alloc(ALIGNED_SIZE(sizeof(struct cons)),
 146                                 BOXED_PAGE_FLAG);
 147
 148     ptr->car = car;
 149     ptr->cdr = cdr;
 150
 151     return make_lispobj(ptr, LIST_POINTER_LOWTAG);
 152 }
 153
 154 lispobj
 155 alloc_number(long n)
 156 {
 157     struct bignum *ptr;
 158
 159     if (-0x20000000 < n && n < 0x20000000)
 160         return make_fixnum(n);
 161     else {
 162         ptr = (struct bignum *)alloc_unboxed(BIGNUM_WIDETAG, 1);
 163
 164         ptr->digits[0] = n;
 165
 166         return make_lispobj(ptr, OTHER_POINTER_LOWTAG);
 167     }
 168 }
 169
 170 lispobj
 171 alloc_base_string(char *str)
 172 {
 173     int len = strlen(str);
 174     lispobj result = alloc_vector(SIMPLE_BASE_STRING_WIDETAG, len+1, 8,
 175                                   UNBOXED_PAGE_FLAG);
 176     struct vector *vec = (struct vector *)native_pointer(result);
 177
 178     vec->length = make_fixnum(len);
 179     strcpy((char *)vec->data, str);
 180
 181     return result;
 182 }
 183
 184 lispobj
 185 alloc_sap(void *ptr)
 186 {
 187     struct sap *sap;
 188     sap=(struct sap *)
 189         alloc_unboxed((int)SAP_WIDETAG, sizeof(struct sap)/sizeof(lispobj) -1);
 190     sap->pointer = ptr;
 191     return make_lispobj(sap,OTHER_POINTER_LOWTAG);
 192 }
 193
 194 lispobj
 195 alloc_code_object (unsigned boxed, unsigned unboxed) {
 196     struct code * code;
 197     /* Coming in, boxed is the number of boxed words requested.
 198      * Converting it to a fixnum makes it measured in bytes. It's also
 199      * rounded up to double word along the way. */
 200     boxed = make_fixnum(boxed + 1 +
 201                         (offsetof(struct code, trace_table_offset) >>
 202                          WORD_SHIFT));
 203     boxed &= ~LOWTAG_MASK;
 204
 205     /* Unboxed is in bytes, round it up to double word boundary. Now
 206      * it's also a fixnum containing the number of unboxed words. */
 207     unboxed += LOWTAG_MASK;
 208     unboxed &= ~LOWTAG_MASK;
 209
 210     code = (struct code *)pa_alloc(boxed + unboxed, CODE_PAGE_FLAG);
 211
 212     /* It used to be that even on gencgc builds the
 213      * ALLOCATE-CODE-OBJECT VOP did all this initialization within
 214      * pseudo atomic. Here, we rely on gc being inhibited. */
 215     if (SymbolValue(GC_INHIBIT, arch_os_get_current_thread()) == NIL)
 216         lose("alloc_code_object called with GC enabled.");
 217     boxed = boxed << (N_WIDETAG_BITS - WORD_SHIFT);
 218     code->header = boxed | CODE_HEADER_WIDETAG;
 219     code->code_size = unboxed;
 220     code->entry_points = NIL;
 221     code->debug_info = NIL;
 222     return make_lispobj(code, OTHER_POINTER_LOWTAG);
 223 }