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Add an inlined jit fast-path for allocate-words/immediate

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* libguile/intrinsics.c (allocate_words_with_freelist)
  (scm_bootstrap_intrinsics):
* libguile/intrinsics.h (SCM_FOR_ALL_VM_INTRINSICS): New intrinsic.
* libguile/jit.c (compile_allocate_words_immediate): Add fast-path.
  A marginal improvement.
This commit is contained in:
Andy Wingo 2019-06-20 14:02:05 +02:00
parent 33aecf48b0
commit 89e28df1c9
3 changed files with 46 additions and 7 deletions
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42
libguile/jit.c
View file

@ -32,6 +32,7 @@
#include "frames.h"
#include "gsubr.h"
#include "gc-inline.h"
#include "instructions.h"
#include "intrinsics.h"
#include "simpos.h" /* scm_getenv_int */
@ -2056,14 +2057,41 @@ compile_allocate_words (scm_jit_state *j, uint16_t dst, uint16_t nwords)
static void
compile_allocate_words_immediate (scm_jit_state *j, uint16_t dst, uint16_t nwords)
{
jit_gpr_t t = T0;
size_t bytes = nwords * sizeof(SCM);
size_t idx = scm_inline_gc_bytes_to_freelist_index (bytes);
emit_store_current_ip (j, t);
emit_call_2 (j, scm_vm_intrinsics.allocate_words, thread_operand (),
jit_operand_imm (JIT_OPERAND_ABI_WORD, nwords));
emit_retval (j, t);
emit_reload_sp (j);
emit_sp_set_scm (j, dst, t);
if (SCM_UNLIKELY (idx >= SCM_INLINE_GC_FREELIST_COUNT))
{
jit_gpr_t t = T0;
emit_store_current_ip (j, t);
emit_call_1 (j, GC_malloc, jit_operand_imm (JIT_OPERAND_ABI_WORD, bytes));
emit_retval (j, t);
emit_reload_sp (j);
emit_sp_set_scm (j, dst, t);
}
else
{
jit_gpr_t res = T0;
ptrdiff_t offset = offsetof(struct scm_thread, freelists);
offset += idx * sizeof(void*);
emit_ldxi (j, res, THREAD, offset);
jit_reloc_t fast = jit_bnei (j->jit, res, 0);
emit_store_current_ip (j, res);
emit_call_2 (j, scm_vm_intrinsics.allocate_words_with_freelist,
thread_operand (),
jit_operand_imm (JIT_OPERAND_ABI_WORD, idx));
emit_retval (j, res);
emit_reload_sp (j);
jit_reloc_t done = jit_jmp (j->jit);
jit_patch_here (j->jit, fast);
jit_gpr_t new_freelist = T1;
emit_ldr (j, new_freelist, res);
jit_stxi (j->jit, offset, THREAD, new_freelist);
jit_patch_here (j->jit, done);
emit_sp_set_scm (j, dst, res);
}
}
static void