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 #ifndef LISP_FEATURE_SB_SAFEPOINT
  44     /* SIG_STOP_FOR_GC must be unblocked: else two threads racing here
  45      * may deadlock: one will wait on the GC lock, and the other
  46      * cannot stop the first one... */
  47     check_gc_signals_unblocked_or_lose(0);
  48 #endif
  49
  50     /* FIXME: OOAO violation: see arch_pseudo_* */
  51     set_pseudo_atomic_atomic(th);
  52     result = general_alloc(bytes, page_type_flag);
  53 #if 0
  54     /* See how the runtime deals with GC being triggerred. */
  55     if ((SymbolValue(GC_PENDING,th) == NIL) &&
  56         (SymbolValue(GC_INHIBIT,th) == NIL) &&
  57         (random() < RAND_MAX/100)) {
  58         SetSymbolValue(GC_PENDING,T,th);
  59         set_pseudo_atomic_interrupted(th);
  60         maybe_save_gc_mask_and_block_deferrables(NULL);
  61     }
  62 #endif
  63     clear_pseudo_atomic_atomic(th);
  64
  65     if (get_pseudo_atomic_interrupted(th)) {
  66         /* WARNING KLUDGE FIXME: pa_alloc() is not pseudo-atomic on
  67          * anything but x86[-64]. maybe_defer_handler doesn't defer
  68          * interrupts if foreign_function_call_active
  69          *
  70          * If the C stack is not scavenged during GC, result needs to
  71          * be protected against not being referred to by any roots, so
  72          * we push it onto the lisp control stack, and read it back
  73          * off after any potential GC has finished */
  74 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  75 #ifdef LISP_FEATURE_STACK_GROWS_DOWNWARD_NOT_UPWARD
  76 #error "!C_STACK_IS_CONTROL_STACK and STACK_GROWS_DOWNWARD_NOT_UPWARD is not supported"
  77 #endif
  78         *access_control_stack_pointer(th) = (lispobj) result;
  79         access_control_stack_pointer(th) += 1;
  80 #endif
  81         do_pending_interrupt();
  82 #ifndef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
  83         access_control_stack_pointer(th) -= 1;
  84         result = (lispobj *) *access_control_stack_pointer(th);
  85 #endif
  86     }
  87     return result;
  88 }
  89 #else
  90 static lispobj *
  91 pa_alloc(int bytes, int page_type_flag)
  92 {
  93     lispobj *result;
  94
  95     /* This is not pseudo atomic at all, but is called only from
  96      * interrupt safe places like interrupt handlers. MG -
  97      * 2005-08-09 */
  98     check_deferrables_blocked_or_lose(0);
  99
 100     result = dynamic_space_free_pointer;
 101
 102     /* Align up to next dual word boundary. */
 103     bytes = ALIGNED_SIZE(bytes);
 104
 105     dynamic_space_free_pointer = (lispobj *)((char *)result + bytes);
 106
 107     if (current_auto_gc_trigger
 108         && dynamic_space_free_pointer > current_auto_gc_trigger) {
 109         clear_auto_gc_trigger();
 110         set_auto_gc_trigger((char *)dynamic_space_free_pointer
 111                             - (char *)current_dynamic_space);
 112     }
 113     return result;
 114 }
 115 #endif
 116
 117 static lispobj *
 118 alloc_unboxed(int type, int words)
 119 {
 120     lispobj *result;
 121
 122     result = pa_alloc(ALIGNED_SIZE((1 + words) * sizeof(lispobj)),
 123                       UNBOXED_PAGE_FLAG);
 124     *result = (lispobj) (words << N_WIDETAG_BITS) | type;
 125     return result;
 126 }
 127
 128 static lispobj
 129 alloc_vector(int type, int length, int size, int page_type_flag)
 130 {
 131     struct vector *result;
 132
 133     result = (struct vector *)
 134         pa_alloc(ALIGNED_SIZE((2 + (length*size + 31) / 32) * sizeof(lispobj)),
 135                  page_type_flag);
 136
 137     result->header = type;
 138     result->length = make_fixnum(length);
 139
 140     return make_lispobj(result,OTHER_POINTER_LOWTAG);
 141 }
 142
 143 lispobj
 144 alloc_cons(lispobj car, lispobj cdr)
 145 {
 146     struct cons *ptr =
 147         (struct cons *)pa_alloc(ALIGNED_SIZE(sizeof(struct cons)),
 148                                 BOXED_PAGE_FLAG);
 149
 150     ptr->car = car;
 151     ptr->cdr = cdr;
 152
 153     return make_lispobj(ptr, LIST_POINTER_LOWTAG);
 154 }
 155
 156 lispobj
 157 alloc_number(long n)
 158 {
 159     struct bignum *ptr;
 160
 161     if (-0x20000000 < n && n < 0x20000000)
 162         return make_fixnum(n);
 163     else {
 164         ptr = (struct bignum *)alloc_unboxed(BIGNUM_WIDETAG, 1);
 165
 166         ptr->digits[0] = n;
 167
 168         return make_lispobj(ptr, OTHER_POINTER_LOWTAG);
 169     }
 170 }
 171
 172 lispobj
 173 alloc_base_string(char *str)
 174 {
 175     int len = strlen(str);
 176     lispobj result = alloc_vector(SIMPLE_BASE_STRING_WIDETAG, len+1, 8,
 177                                   UNBOXED_PAGE_FLAG);
 178     struct vector *vec = (struct vector *)native_pointer(result);
 179
 180     vec->length = make_fixnum(len);
 181     strcpy((char *)vec->data, str);
 182
 183     return result;
 184 }
 185
 186 lispobj
 187 alloc_sap(void *ptr)
 188 {
 189     struct sap *sap;
 190     sap=(struct sap *)
 191         alloc_unboxed((int)SAP_WIDETAG, sizeof(struct sap)/sizeof(lispobj) -1);
 192     sap->pointer = ptr;
 193     return make_lispobj(sap,OTHER_POINTER_LOWTAG);
 194 }
 195
 196 lispobj
 197 alloc_code_object (unsigned boxed, unsigned unboxed) {
 198     struct code * code;
 199     /* Coming in, boxed is the number of boxed words requested.
 200      * Converting it to a fixnum makes it measured in bytes. It's also
 201      * rounded up to double word along the way. */
 202     boxed = (boxed + 1 +
 203              (offsetof(struct code, trace_table_offset) >>
 204               WORD_SHIFT)) << WORD_SHIFT;
 205     boxed &= ~LOWTAG_MASK;
 206
 207     /* Unboxed is in bytes, round it up to double word boundary. Now
 208      * it's also a fixnum containing the number of unboxed words. */
 209     unboxed += LOWTAG_MASK;
 210     unboxed &= ~LOWTAG_MASK;
 211
 212     code = (struct code *)pa_alloc(boxed + unboxed, CODE_PAGE_FLAG);
 213
 214     /* It used to be that even on gencgc builds the
 215      * ALLOCATE-CODE-OBJECT VOP did all this initialization within
 216      * pseudo atomic. Here, we rely on gc being inhibited. */
 217     if (SymbolValue(GC_INHIBIT, arch_os_get_current_thread()) == NIL)
 218         lose("alloc_code_object called with GC enabled.");
 219     boxed = boxed << (N_WIDETAG_BITS - WORD_SHIFT);
 220     code->header = boxed | CODE_HEADER_WIDETAG;
 221     code->code_size = unboxed >> (WORD_SHIFT - N_FIXNUM_TAG_BITS);
 222     code->entry_points = NIL;
 223     code->debug_info = NIL;
 224     return make_lispobj(code, OTHER_POINTER_LOWTAG);
 225 }