forked from osmocom/wireshark
dfilter: Allow variable number of jumps during codegen
Use a list to allow a variable number of jumps, instead of a fixed count. The flexibility in the number of jumps a given syntax tree node might need to handle is useful to add new kinds of operations.
This commit is contained in:
João Valverde
A Wireshark GitLab Utility
parent
5f13127a94
commit
588d22a82b
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@ -19,11 +19,14 @@
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#include "ftypes/ftypes.h"
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#include <wsutil/ws_assert.h>
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static void
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fixup_jumps(gpointer data, gpointer user_data);
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static void
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gencode(dfwork_t *dfw, stnode_t *st_node);
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static int
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gen_entity(dfwork_t *dfw, stnode_t *st_arg, dfvm_value_t **p_jmp);
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gen_entity(dfwork_t *dfw, stnode_t *st_arg, GSList **jumps_ptr);
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static void
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dfw_append_insn(dfwork_t *dfw, dfvm_insn_t *insn)
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@ -121,7 +124,7 @@ dfw_append_put_fvalue(dfwork_t *dfw, fvalue_t *fv)
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/* returns register number */
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static int
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dfw_append_mk_range(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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dfw_append_mk_range(dfwork_t *dfw, stnode_t *node, GSList **jumps_ptr)
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{
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int hf_reg, reg;
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stnode_t *entity;
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@ -131,7 +134,7 @@ dfw_append_mk_range(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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entity = sttype_range_entity(node);
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/* XXX, check if p_jmp logic is OK */
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hf_reg = gen_entity(dfw, entity, p_jmp);
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hf_reg = gen_entity(dfw, entity, jumps_ptr);
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insn = dfvm_insn_new(MK_RANGE);
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@ -157,20 +160,16 @@ dfw_append_mk_range(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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/* returns register number that the functions's result will be in. */
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static int
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dfw_append_function(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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dfw_append_function(dfwork_t *dfw, stnode_t *node, GSList **jumps_ptr)
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{
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GSList *params;
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int i, num_params, reg;
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dfvm_value_t **jmps;
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int i, reg;
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GSList *param_jumps = NULL;
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dfvm_value_t *jmp;
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dfvm_insn_t *insn;
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dfvm_value_t *val1, *val2, *val;
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params = sttype_function_params(node);
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num_params = g_slist_length(params);
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/* Array to hold the instructions that need to jump to
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* an instruction if they fail. */
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jmps = (dfvm_value_t **)g_malloc0(num_params * sizeof(dfvm_value_t*));
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/* Create the new DFVM instruction */
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insn = dfvm_insn_new(CALL_FUNCTION);
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@ -186,7 +185,7 @@ dfw_append_function(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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i = 0;
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while (params) {
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reg = gen_entity(dfw, (stnode_t *)params->data, &jmps[i]);
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reg = gen_entity(dfw, (stnode_t *)params->data, ¶m_jumps);
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val = dfvm_value_new(REGISTER);
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val->value.numeric = reg;
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@ -213,21 +212,17 @@ dfw_append_function(dfwork_t *dfw, stnode_t *node, dfvm_value_t **p_jmp)
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* after we caled dfw_append_insn above so that
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* we know what the next DFVM insruction is, via
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* dfw->next_insn_id */
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for (i = 0; i < num_params; i++) {
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if (jmps[i]) {
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jmps[i]->value.numeric = dfw->next_insn_id;
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}
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}
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g_slist_foreach(param_jumps, fixup_jumps, dfw);
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g_slist_free(param_jumps);
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param_jumps = NULL;
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/* We need another instruction to jump to another exit
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* place, if the call() of our function failed for some reaosn */
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insn = dfvm_insn_new(IF_FALSE_GOTO);
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ws_assert(p_jmp);
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*p_jmp = dfvm_value_new(INSN_NUMBER);
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insn->arg1 = *p_jmp;
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jmp = dfvm_value_new(INSN_NUMBER);
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insn->arg1 = jmp;
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dfw_append_insn(dfw, insn);
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g_free(jmps);
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*jumps_ptr = g_slist_prepend(*jumps_ptr, jmp);
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return val2->value.numeric;
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}
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@ -277,25 +272,21 @@ gen_relation_regs(dfwork_t *dfw, dfvm_opcode_t op, int reg1, int reg2)
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static void
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gen_relation(dfwork_t *dfw, dfvm_opcode_t op, stnode_t *st_arg1, stnode_t *st_arg2)
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{
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dfvm_value_t *jmp1 = NULL, *jmp2 = NULL;
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GSList *jumps = NULL;
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int reg1 = -1, reg2 = -1;
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/* Create code for the LHS and RHS of the relation */
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reg1 = gen_entity(dfw, st_arg1, &jmp1);
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reg2 = gen_entity(dfw, st_arg2, &jmp2);
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reg1 = gen_entity(dfw, st_arg1, &jumps);
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reg2 = gen_entity(dfw, st_arg2, &jumps);
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/* Then combine them in a DFVM insruction */
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gen_relation_regs(dfw, op, reg1, reg2);
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/* If either of the relation arguments need an "exit" instruction
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* to jump to (on failure), mark them */
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if (jmp1) {
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jmp1->value.numeric = dfw->next_insn_id;
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}
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if (jmp2) {
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jmp2->value.numeric = dfw->next_insn_id;
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}
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g_slist_foreach(jumps, fixup_jumps, dfw);
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g_slist_free(jumps);
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jumps = NULL;
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}
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static void
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@ -316,14 +307,14 @@ gen_relation_in(dfwork_t *dfw, stnode_t *st_arg1, stnode_t *st_arg2)
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{
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dfvm_insn_t *insn;
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dfvm_value_t *val1, *val2, *val3;
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dfvm_value_t *jmp1 = NULL, *jmp2 = NULL, *jmp3 = NULL;
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GSList *jumps = NULL;
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GSList *node_jumps = NULL;
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int reg1;
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stnode_t *node1, *node2;
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GSList *nodelist_head, *nodelist;
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GSList *jumplist = NULL;
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/* Create code for the LHS of the relation */
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reg1 = gen_entity(dfw, st_arg1, &jmp1);
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reg1 = gen_entity(dfw, st_arg1, &jumps);
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/* Create code for the set on the RHS of the relation */
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nodelist_head = nodelist = (GSList*)stnode_steal_data(st_arg2);
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@ -337,8 +328,8 @@ gen_relation_in(dfwork_t *dfw, stnode_t *st_arg1, stnode_t *st_arg2)
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int reg2, reg3;
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/* Range element: add lower/upper bound test. */
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reg2 = gen_entity(dfw, node1, &jmp2);
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reg3 = gen_entity(dfw, node2, &jmp3);
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reg2 = gen_entity(dfw, node1, &node_jumps);
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reg3 = gen_entity(dfw, node2, &node_jumps);
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/* Add test to see if the item is in range. */
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insn = dfvm_insn_new(ANY_IN_RANGE);
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@ -356,7 +347,7 @@ gen_relation_in(dfwork_t *dfw, stnode_t *st_arg1, stnode_t *st_arg2)
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int reg2;
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/* Normal element: add equality test. */
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reg2 = gen_entity(dfw, node1, &jmp2);
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reg2 = gen_entity(dfw, node1, &node_jumps);
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/* Add test to see if the item matches */
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gen_relation_regs(dfw, ANY_EQ, reg1, reg2);
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@ -368,29 +359,21 @@ gen_relation_in(dfwork_t *dfw, stnode_t *st_arg1, stnode_t *st_arg2)
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val1 = dfvm_value_new(INSN_NUMBER);
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insn->arg1 = val1;
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dfw_append_insn(dfw, insn);
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jumplist = g_slist_prepend(jumplist, val1);
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jumps = g_slist_prepend(jumps, val1);
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}
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/* If an item is not present, just jump to the next item */
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if (jmp2) {
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jmp2->value.numeric = dfw->next_insn_id;
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jmp2 = NULL;
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}
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if (jmp3) {
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jmp3->value.numeric = dfw->next_insn_id;
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jmp3 = NULL;
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}
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g_slist_foreach(node_jumps, fixup_jumps, dfw);
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g_slist_free(node_jumps);
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node_jumps = NULL;
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}
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/* Jump here if the LHS entity was not present */
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if (jmp1) {
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jmp1->value.numeric = dfw->next_insn_id;
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}
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/* Jump here if any of the items in the set matched */
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g_slist_foreach(jumplist, fixup_jumps, dfw);
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g_slist_foreach(jumps, fixup_jumps, dfw);
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g_slist_free(jumps);
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jumps = NULL;
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/* Clean up */
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g_slist_free(jumplist);
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set_nodelist_free(nodelist_head);
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}
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@ -399,10 +382,11 @@ gen_relation_in(dfwork_t *dfw, stnode_t *st_arg1, stnode_t *st_arg2)
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* be set to the place to jump to, to return to the calling code,
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* if the load of a field from the proto_tree fails. */
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static int
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gen_entity(dfwork_t *dfw, stnode_t *st_arg, dfvm_value_t **p_jmp)
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gen_entity(dfwork_t *dfw, stnode_t *st_arg, GSList **jumps_ptr)
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{
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sttype_id_t e_type;
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dfvm_insn_t *insn;
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dfvm_value_t *jmp;
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header_field_info *hfinfo;
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int reg = -1;
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e_type = stnode_type_id(st_arg);
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@ -412,19 +396,19 @@ gen_entity(dfwork_t *dfw, stnode_t *st_arg, dfvm_value_t **p_jmp)
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reg = dfw_append_read_tree(dfw, hfinfo);
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insn = dfvm_insn_new(IF_FALSE_GOTO);
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ws_assert(p_jmp);
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*p_jmp = dfvm_value_new(INSN_NUMBER);
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insn->arg1 = *p_jmp;
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jmp = dfvm_value_new(INSN_NUMBER);
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insn->arg1 = jmp;
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dfw_append_insn(dfw, insn);
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*jumps_ptr = g_slist_prepend(*jumps_ptr, jmp);
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}
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else if (e_type == STTYPE_FVALUE) {
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reg = dfw_append_put_fvalue(dfw, (fvalue_t *)stnode_steal_data(st_arg));
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}
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else if (e_type == STTYPE_RANGE) {
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reg = dfw_append_mk_range(dfw, st_arg, p_jmp);
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reg = dfw_append_mk_range(dfw, st_arg, jumps_ptr);
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}
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else if (e_type == STTYPE_FUNCTION) {
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reg = dfw_append_function(dfw, st_arg, p_jmp);
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reg = dfw_append_function(dfw, st_arg, jumps_ptr);
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}
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else if (e_type == STTYPE_PCRE) {
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reg = dfw_append_put_pcre(dfw, stnode_steal_data(st_arg));
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