125 lines
5.9 KiB
C
125 lines
5.9 KiB
C
/****************************************************************
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* *
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* Copyright 2010, 2013 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include "gtm_stdio.h"
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#include "gtm_string.h"
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#include <rtnhdr.h>
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#include "stack_frame.h"
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#include "op.h"
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#include "lv_val.h"
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#include "gdsroot.h"
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#include "gtm_facility.h"
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#include "fileinfo.h"
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#include "gdsbt.h"
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#include "gdsfhead.h"
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#include "alias.h"
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#include "min_max.h"
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GBLREF stack_frame *frame_pointer;
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GBLREF symval *curr_symval;
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GBLREF uint4 dollar_tlevel;
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GBLREF lv_val *active_lv;
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GBLREF mval *alias_retarg;
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/* Operation - The destination variable becomes a new alias of the data pointed to by the source container variable:
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*
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* 1) Index into the variable name table to get the variable name for the new alias (destination).
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* 2) Create the hash for the variable and look up in hash table (adding if not yet created).
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* 3) See if hash entry has a value pointer. If yes and same as source var, we are done (NOOP).
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* 4) Set hash entry to point to new lv_val.
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* 5) Whichever symval of source container or the alias it pointed to has the largest address, that symval is the
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* earliest symval affected by this alias action. Mark all interveening symvals (end points included) as having
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* had alias activity via MARK_ALIAS_ACTIVE macro. This is so we can properly handle issues in an exlusive NEW
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* situation involving multiple symvals and potential aliasing between them.
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*
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* Note that this opcode's function is very similar to "op_setalsctin2als" but is necessarily different because the
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* source container is in a temporary mval passed back through a function rather than the lv_val that "op_setalsctin2als"
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* deals with. Consequently, the amount of verification we can do is reduced. But this is acceptable due to the checks
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* done by "unw_retarg" and "op_exfunretals" which pre-processed this value for us. There is also different reference
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* count maintenance to do than the "op_setalsctin2als" opcode. With substantially more work to reorganize how SET
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* operates, it would likely be possible to combine these functions but the way things are structured now, all the
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* set functions plus "op_sto" share the same API so adding a parm to one means adding a useless parm to all 6 of
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* them which is not acceptable so we end up duplicating portions of code here.
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*/
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void op_setfnretin2als(mval *srcmv, int destindx)
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{
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ht_ent_mname *tabent;
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mname_entry *varname;
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lv_val *srclvc, *dstlv;
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int4 srcsymvlvl;
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boolean_t added;
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assert(alias_retarg == srcmv);
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assert(srcmv);
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assert(srcmv->mvtype & MV_ALIASCONT);
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assert(MVAL_IN_RANGE(srcmv, frame_pointer->temps_ptr, frame_pointer->temp_mvals)); /* Verify is a temp mval */
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srclvc = (lv_val *)srcmv->str.addr;
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assert(srclvc);
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assert(LV_IS_BASE_VAR(srclvc)); /* Verify base var */
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assert(srclvc->stats.trefcnt >= srclvc->stats.crefcnt);
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assert(1 <= srclvc->stats.crefcnt); /* Verify we have an existing container reference */
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srcsymvlvl = LV_SYMVAL(srclvc)->symvlvl; /* lv_val may go away below so record symlvl */
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varname = &(((mname_entry *)frame_pointer->vartab_ptr)[destindx]);
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DEBUG_ONLY(added = FALSE);
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/* Find hash table entry */
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if (NULL == (tabent = (ht_ent_mname *)frame_pointer->l_symtab[destindx])) /* note tabent assignment */
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{ /* No fast path to hash table entry -- look it up the hard(er) way */
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varname = &(((mname_entry *)frame_pointer->vartab_ptr)[destindx]);
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added = add_hashtab_mname_symval(&curr_symval->h_symtab, varname, NULL, &tabent);
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}
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assert(tabent);
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assert(tabent || added);
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dstlv = (lv_val *)tabent->value;
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if (NULL == dstlv && curr_symval->tp_save_all)
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{ /* dstlv does not exist yet we need to be able to save a previous "novalue" lvval in case a TPRESTART
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needs to restore the value. Create a var so its undefined status can be saved.
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*/
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lv_newname(tabent, curr_symval);
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dstlv = (lv_val *)tabent->value;
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assert(dstlv);
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}
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/* No need to increment before dstlv processing to prevent removal of last reference to srclvc in this case because
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* the increment has already been done in "unw_retarg".
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*/
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if (dstlv)
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{
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assert(LV_IS_BASE_VAR(dstlv)); /* Verify base var */
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if (dollar_tlevel && NULL != dstlv->tp_var && !dstlv->tp_var->var_cloned)
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TP_VAR_CLONE(dstlv);
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assert(0 < dstlv->stats.trefcnt);
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assert(0 < (dstlv->stats.trefcnt - dstlv->stats.crefcnt)); /* Make sure there is one non-container reference */
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DECR_TREFCNT(dstlv);
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assert(dstlv->stats.trefcnt >= dstlv->stats.crefcnt);
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if (0 == dstlv->stats.trefcnt)
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{ /* Non alias -- make room for an alias to live here instead */
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lv_kill(dstlv, DOTPSAVE_TRUE, DO_SUBTREE_TRUE);
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LV_FREESLOT(dstlv);
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} /* Else alias pointer in the hash table is just replaced below */
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}
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DECR_CREFCNT(srclvc); /* In "unw_retarg" we incremented for a container but is now "just" an alias so get rid of
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* the container count from the temp return parm */
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frame_pointer->l_symtab[destindx] = tabent;
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DBGRFCT((stderr, "op_setfnret2als: hte 0x"lvaddr" being reset from 0x"lvaddr" to 0x"lvaddr"\n",
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tabent, tabent->value, srclvc));
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tabent->value = (void *)srclvc;
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/* These symvals have had alias activity - Note the possibility of re-marking srcsymvlvl is not necessarily re-doing
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* the mark done by "unw_retarg" since the source lv_val may have been re-created if it was originally in an xnew'd
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* symtab which popped during the return.
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*/
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MARK_ALIAS_ACTIVE(MIN(srcsymvlvl, LV_SYMVAL(srclvc)->symvlvl));
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active_lv = (lv_val *)NULL; /* if we get here, subscript set was successful. clear active_lv to avoid later
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cleanup problems */
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alias_retarg = NULL;
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}
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