+ /* The first 'n_call' tokens in 'pp', which we bracket as C0...C1, inclusive,
+ are a macro call. (These are likely to be the only tokens in 'pp'.)
+ Expand them. */
+ const struct lex_token *c0 = lex_stage_first (&src->pp);
+ const struct lex_token *c1 = lex_stage_nth (&src->pp, n_call - 1);
+ struct macro_tokens expansion = { .n = 0 };
+ struct msg_location loc = lex_token_location (src, c0, c1);
+ macro_call_expand (mc, src->reader->syntax, &loc, &expansion);
+ macro_call_destroy (mc);
+
+ /* Convert the macro expansion into syntax for possible error messages
+ later. */
+ size_t *ofs = xnmalloc (expansion.n, sizeof *ofs);
+ size_t *len = xnmalloc (expansion.n, sizeof *len);
+ struct string s = DS_EMPTY_INITIALIZER;
+ macro_tokens_to_syntax (&expansion, &s, ofs, len);
+
+ if (settings_get_mprint ())
+ output_item_submit (text_item_create (TEXT_ITEM_LOG, ds_cstr (&s),
+ _("Macro Expansion")));
+
+ /* Append the macro expansion tokens to the lookahead. */
+ if (expansion.n > 0)
+ {
+ char *macro_rep = ds_steal_cstr (&s);
+ size_t *ref_cnt = xmalloc (sizeof *ref_cnt);
+ *ref_cnt = expansion.n;
+ for (size_t i = 0; i < expansion.n; i++)
+ {
+ struct lex_token *token = xmalloc (sizeof *token);
+ *token = (struct lex_token) {
+ .token = expansion.mts[i].token,
+ .token_pos = c0->token_pos,
+ .token_len = (c1->token_pos + c1->token_len) - c0->token_pos,
+ .first_line = c0->first_line,
+ .macro_rep = macro_rep,
+ .ofs = ofs[i],
+ .len = len[i],
+ .ref_cnt = ref_cnt,
+ };
+ lex_stage_push_last (&src->merge, token);
+
+ ss_dealloc (&expansion.mts[i].syntax);
+ }
+ }
+ else
+ ds_destroy (&s);
+ free (expansion.mts);
+ free (ofs);
+ free (len);
+
+ /* Destroy the tokens for the call. */
+ for (size_t i = 0; i < n_call; i++)
+ lex_stage_pop_first (&src->pp);
+
+ return expansion.n > 0;
+}
+
+/* Attempts to obtain at least one new token into 'merge' in SRC.
+
+ Returns true if successful, false on failure. In the latter case, SRC is
+ exhausted and 'src->eof' is now true. */
+static bool
+lex_source_get_merge (struct lex_source *src)
+{
+ while (!src->eof)
+ if (lex_source_try_get_merge (src))
+ return true;
+ return false;
+}
+
+/* Attempts to obtain at least one new token into 'lookahead' in SRC.
+
+ Returns true if successful, false on failure. In the latter case, SRC is
+ exhausted and 'src->eof' is now true. */
+static bool
+lex_source_get_parse (struct lex_source *src)
+{
+ struct merger m = MERGER_INIT;
+ struct token out;
+ for (size_t i = 0; ; i++)
+ {
+ while (lex_stage_count (&src->merge) <= i && !lex_source_get_merge (src))
+ {
+ /* We always get a T_ENDCMD at the end of an input file
+ (transformed from T_STOP by lex_source_try_get_pp()) and
+ merger_add() should never return -1 on T_ENDCMD. */
+ assert (lex_stage_is_empty (&src->merge));
+ return false;
+ }
+
+ int retval = merger_add (&m, &lex_stage_nth (&src->merge, i)->token,
+ &out);
+ if (!retval)
+ {
+ lex_source_push_parse (src, lex_stage_take_first (&src->merge));
+ return true;
+ }
+ else if (retval > 0)
+ {
+ /* Add a token that merges all the tokens together. */
+ const struct lex_token *first = lex_stage_first (&src->merge);
+ const struct lex_token *last = lex_stage_nth (&src->merge,
+ retval - 1);
+ bool macro = first->macro_rep && first->macro_rep == last->macro_rep;
+ struct lex_token *t = xmalloc (sizeof *t);
+ *t = (struct lex_token) {
+ .token = out,
+ .token_pos = first->token_pos,
+ .token_len = (last->token_pos - first->token_pos) + last->token_len,
+ .first_line = first->first_line,
+
+ /* This works well if all the tokens were not expanded from macros,
+ or if they came from the same macro expansion. It just gives up
+ in the other (corner) cases. */
+ .macro_rep = macro ? first->macro_rep : NULL,
+ .ofs = macro ? first->ofs : 0,
+ .len = macro ? (last->ofs - first->ofs) + last->len : 0,
+ .ref_cnt = macro ? first->ref_cnt : NULL,
+ };
+ if (t->ref_cnt)
+ ++*t->ref_cnt;
+ lex_source_push_parse (src, t);
+
+ for (int i = 0; i < retval; i++)
+ lex_stage_pop_first (&src->merge);
+ return true;
+ }
+ }