diff options
Diffstat (limited to 'Python/compile.c')
| -rw-r--r-- | Python/compile.c | 92 |
1 files changed, 90 insertions, 2 deletions
diff --git a/Python/compile.c b/Python/compile.c index b4377ec..36c78aa 100644 --- a/Python/compile.c +++ b/Python/compile.c @@ -1891,6 +1891,7 @@ com_assign(c, n, assigning) } } } + /* Forward */ static node *get_rawdocstring PROTO((node *)); static void @@ -2170,6 +2171,90 @@ com_exec_stmt(c, n) com_pop(c, 3); } +static int +is_constant_false(c, n) + struct compiling *c; + node *n; +{ + object *v; + int i; + + /* Label to avoid tail recursion */ + next: + switch (TYPE(n)) { + + case suite: + if (NCH(n) == 1) { + n = CHILD(n, 0); + goto next; + } + /* Fall through */ + case file_input: + for (i = 0; i < NCH(n); i++) { + node *ch = CHILD(n, i); + if (TYPE(ch) == stmt) { + n = ch; + goto next; + } + } + break; + + case stmt: + case simple_stmt: + case small_stmt: + n = CHILD(n, 0); + goto next; + + case expr_stmt: + case testlist: + case test: + case and_test: + case not_test: + case comparison: + case expr: + case xor_expr: + case and_expr: + case shift_expr: + case arith_expr: + case term: + case factor: + case power: + case atom: + if (NCH(n) == 1) { + n = CHILD(n, 0); + goto next; + } + break; + + case NAME: + if (Py_OptimizeFlag && strcmp(STR(n), "__debug__") == 0) + return 1; + break; + + case NUMBER: + v = parsenumber(c, STR(n)); + if (v == NULL) { + err_clear(); + break; + } + i = testbool(v); + DECREF(v); + return i == 0; + + case STRING: + v = parsestrplus(n); + if (v == NULL) { + err_clear(); + break; + } + i = testbool(v); + DECREF(v); + return i == 0; + + } + return 0; +} + static void com_if_stmt(c, n) struct compiling *c; @@ -2182,9 +2267,11 @@ com_if_stmt(c, n) for (i = 0; i+3 < NCH(n); i+=4) { int a = 0; node *ch = CHILD(n, i+1); + if (is_constant_false(c, ch)) + continue; if (i > 0) com_addoparg(c, SET_LINENO, ch->n_lineno); - com_node(c, CHILD(n, i+1)); + com_node(c, ch); com_addfwref(c, JUMP_IF_FALSE, &a); com_addbyte(c, POP_TOP); com_pop(c, 1); @@ -2196,7 +2283,8 @@ com_if_stmt(c, n) } if (i+2 < NCH(n)) com_node(c, CHILD(n, i+2)); - com_backpatch(c, anchor); + if (anchor) + com_backpatch(c, anchor); } static void |