1 files changed, 113 insertions, 0 deletions
diff --git a/AppPkg/Applications/Python/Python-2.7.10/Parser/firstsets.c b/AppPkg/Applications/Python/Python-2.7.10/Parser/firstsets.c
new file mode 100644
index 0000000000..69faf8f09e
--- /dev/null
+++ b/AppPkg/Applications/Python/Python-2.7.10/Parser/firstsets.c
@@ -0,0 +1,113 @@
+
+/* Computation of FIRST stets */
+
+#include "pgenheaders.h"
+#include "grammar.h"
+#include "token.h"
+
+extern int Py_DebugFlag;
+
+/* Forward */
+static void calcfirstset(grammar *, dfa *);
+
+void
+addfirstsets(grammar *g)
+{
+    int i;
+    dfa *d;
+
+    if (Py_DebugFlag)
+        printf("Adding FIRST sets ...\n");
+    for (i = 0; i < g->g_ndfas; i++) {
+        d = &g->g_dfa[i];
+        if (d->d_first == NULL)
+            calcfirstset(g, d);
+    }
+}
+
+static void
+calcfirstset(grammar *g, dfa *d)
+{
+    int i, j;
+    state *s;
+    arc *a;
+    int nsyms;
+    int *sym;
+    int nbits;
+    static bitset dummy;
+    bitset result;
+    int type;
+    dfa *d1;
+    label *l0;
+
+    if (Py_DebugFlag)
+        printf("Calculate FIRST set for '%s'\n", d->d_name);
+
+    if (dummy == NULL)
+        dummy = newbitset(1);
+    if (d->d_first == dummy) {
+        fprintf(stderr, "Left-recursion for '%s'\n", d->d_name);
+        return;
+    }
+    if (d->d_first != NULL) {
+        fprintf(stderr, "Re-calculating FIRST set for '%s' ???\n",
+            d->d_name);
+    }
+    d->d_first = dummy;
+
+    l0 = g->g_ll.ll_label;
+    nbits = g->g_ll.ll_nlabels;
+    result = newbitset(nbits);
+
+    sym = (int *)PyObject_MALLOC(sizeof(int));
+    if (sym == NULL)
+        Py_FatalError("no mem for new sym in calcfirstset");
+    nsyms = 1;
+    sym[0] = findlabel(&g->g_ll, d->d_type, (char *)NULL);
+
+    s = &d->d_state[d->d_initial];
+    for (i = 0; i < s->s_narcs; i++) {
+        a = &s->s_arc[i];
+        for (j = 0; j < nsyms; j++) {
+            if (sym[j] == a->a_lbl)
+                break;
+        }
+        if (j >= nsyms) { /* New label */
+            sym = (int *)PyObject_REALLOC(sym,
+                                    sizeof(int) * (nsyms + 1));
+            if (sym == NULL)
+                Py_FatalError(
+                    "no mem to resize sym in calcfirstset");
+            sym[nsyms++] = a->a_lbl;
+            type = l0[a->a_lbl].lb_type;
+            if (ISNONTERMINAL(type)) {
+                d1 = PyGrammar_FindDFA(g, type);
+                if (d1->d_first == dummy) {
+                    fprintf(stderr,
+                        "Left-recursion below '%s'\n",
+                        d->d_name);
+                }
+                else {
+                    if (d1->d_first == NULL)
+                        calcfirstset(g, d1);
+                    mergebitset(result,
+                                d1->d_first, nbits);
+                }
+            }
+            else if (ISTERMINAL(type)) {
+                addbit(result, a->a_lbl);
+            }
+        }
+    }
+    d->d_first = result;
+    if (Py_DebugFlag) {
+        printf("FIRST set for '%s': {", d->d_name);
+        for (i = 0; i < nbits; i++) {
+            if (testbit(result, i))
+                printf(" %s", PyGrammar_LabelRepr(&l0[i]));
+        }
+        printf(" }\n");
+    }
+
+    PyObject_FREE(sym);
+}