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author | Alan Wu <XrXr@users.noreply.github.com> | 2021-10-18 17:01:40 -0400 |
---|---|---|
committer | Alan Wu <XrXr@users.noreply.github.com> | 2021-10-20 18:19:43 -0400 |
commit | b74d6563a665f225f182c4921db68852bbb7e1f1 (patch) | |
tree | 14a7131d423549cf1ffc661048e7501d5ce5ae24 /yjit_codegen.c | |
parent | 2e2430564aa32b68f9e2d99e1f1e273bee3defda (diff) |
Extract yjit_force_iv_index and make it work when object is frozen
In an effort to simplify the logic YJIT generates for accessing instance
variable, YJIT ensures that a given name-to-index mapping exists at
compile time. In the case that the mapping doesn't exist, it was created
by using rb_ivar_set() with Qundef on the sample object we see at
compile time. This hack isn't fine if the sample object happens to be
frozen, in which case YJIT would raise a FrozenError unexpectedly.
To deal with this, make a new function that only reserves the mapping
but doesn't touch the object. This is rb_obj_ensure_iv_index_mapping().
This new function superceeds the functionality of rb_iv_index_tbl_lookup()
so it was removed.
Reported by and includes a test case from John Hawthorn <john@hawthorn.email>
Fixes: GH-282
Diffstat (limited to 'yjit_codegen.c')
-rw-r--r-- | yjit_codegen.c | 28 |
1 files changed, 5 insertions, 23 deletions
diff --git a/yjit_codegen.c b/yjit_codegen.c index bca5f203ec..136d7d4dea 100644 --- a/yjit_codegen.c +++ b/yjit_codegen.c @@ -1478,33 +1478,12 @@ jit_chain_guard(enum jcc_kinds jcc, jitstate_t *jit, const ctx_t *ctx, uint8_t d } } -bool rb_iv_index_tbl_lookup(struct st_table *iv_index_tbl, ID id, struct rb_iv_index_tbl_entry **ent); // vm_insnhelper.c - enum { GETIVAR_MAX_DEPTH = 10, // up to 5 different classes, and embedded or not for each OPT_AREF_MAX_CHAIN_DEPTH = 2, // hashes and arrays SEND_MAX_DEPTH = 5, // up to 5 different classes }; -static uint32_t -yjit_force_iv_index(VALUE comptime_receiver, VALUE klass, ID name) -{ - ID id = name; - struct rb_iv_index_tbl_entry *ent; - struct st_table *iv_index_tbl = ROBJECT_IV_INDEX_TBL(comptime_receiver); - - // Make sure there is a mapping for this ivar in the index table - if (!iv_index_tbl || !rb_iv_index_tbl_lookup(iv_index_tbl, id, &ent)) { - rb_ivar_set(comptime_receiver, id, Qundef); - iv_index_tbl = ROBJECT_IV_INDEX_TBL(comptime_receiver); - RUBY_ASSERT(iv_index_tbl); - // Redo the lookup - RUBY_ASSERT_ALWAYS(rb_iv_index_tbl_lookup(iv_index_tbl, id, &ent)); - } - - return ent->index; -} - VALUE rb_vm_set_ivar_idx(VALUE obj, uint32_t idx, VALUE val); // Codegen for setting an instance variable. @@ -1523,7 +1502,7 @@ gen_set_ivar(jitstate_t *jit, ctx_t *ctx, VALUE recv, VALUE klass, ID ivar_name) x86opnd_t val_opnd = ctx_stack_pop(ctx, 1); x86opnd_t recv_opnd = ctx_stack_pop(ctx, 1); - uint32_t ivar_index = yjit_force_iv_index(recv, klass, ivar_name); + uint32_t ivar_index = rb_obj_ensure_iv_index_mapping(recv, ivar_name); // Call rb_vm_set_ivar_idx with the receiver, the index of the ivar, and the value mov(cb, C_ARG_REGS[0], recv_opnd); @@ -1596,7 +1575,10 @@ gen_get_ivar(jitstate_t *jit, ctx_t *ctx, const int max_chain_depth, VALUE compt jit_chain_guard(JCC_JNE, jit, &starting_context, max_chain_depth, side_exit); */ - uint32_t ivar_index = yjit_force_iv_index(comptime_receiver, CLASS_OF(comptime_receiver), ivar_name); + // FIXME: Mapping the index could fail when there is too many ivar names. If we're + // compiling for a branch stub that can cause the exception to be thrown from the + // wrong PC. + uint32_t ivar_index = rb_obj_ensure_iv_index_mapping(comptime_receiver, ivar_name); // Pop receiver if it's on the temp stack if (!reg0_opnd.is_self) { |