silence implicit fallthrough gcc warnings

All changes in this patch tries to address implicit fallthrough warnings on the
newer gcc compiler.

Signed-off-by: Ani Sinha <[email protected]>

Author: ani-sinha

Modules/_ctypes/_ctypes.c

@@ -3704,6 +3704,9 @@ _build_callargs(PyCFuncPtrObject *self, PyObject *argtypes,
             *pinoutmask |= (1 << i); /* mark as inout arg */
             (*pnumretvals)++;
             /* fall through to PARAMFLAG_FIN... */
+#if defined(__GNUC__) && __GNUC__ >= 7
+	    __attribute__ ((fallthrough));
+#endif
         case 0:
         case PARAMFLAG_FIN:
             /* 'in' parameter.  Copy it from inargs. */

Modules/zlib/inflate.c

@@ -85,6 +85,10 @@
 #include "inflate.h"
 #include "inffast.h"
 
+#if defined(__GNUC__) && __GNUC__ >= 7
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
+
 #ifdef MAKEFIXED
 #  ifndef BUILDFIXED
 #    define BUILDFIXED

Objects/stringobject.c

@@ -590,6 +590,7 @@ string_dealloc(PyObject *op)
 
         case SSTATE_INTERNED_IMMORTAL:
             Py_FatalError("Immortal interned string died.");
+	    // fall through
 
         default:
             Py_FatalError("Inconsistent interned string state.");

Objects/unicodeobject.c

@@ -796,6 +796,9 @@ PyUnicode_FromFormatV(const char *format, va_list vargs)
 #endif
                 /* fall through... */
             }
+#if defined(__GNUC__) && __GNUC__ >= 7
+	    __attribute__ ((fallthrough));
+#endif
             case '%':
                 n++;
                 break;

Python/ast.c

@@ -549,6 +549,7 @@ ast_for_comp_op(struct compiling *c, const node *n)
                     return In;
                 if (strcmp(STR(n), "is") == 0)
                     return Is;
+		break;
             default:
                 PyErr_Format(PyExc_SystemError, "invalid comp_op: %s",
                              STR(n));
@@ -563,6 +564,7 @@ ast_for_comp_op(struct compiling *c, const node *n)
                     return NotIn;
                 if (strcmp(STR(CHILD(n, 0)), "is") == 0)
                     return IsNot;
+		break;
             default:
                 PyErr_Format(PyExc_SystemError, "invalid comp_op: %s %s",
                              STR(CHILD(n, 0)), STR(CHILD(n, 1)));
@@ -2417,6 +2419,7 @@ ast_for_flow_stmt(struct compiling *c, const node *n)
                 return Raise(expr1, expr2, expr3, LINENO(n), n->n_col_offset,
                              c->c_arena);
             }
+	    break;
         default:
             PyErr_Format(PyExc_SystemError,
                          "unexpected flow_stmt: %d", TYPE(ch));

Python/ceval.c

@@ -19,6 +19,12 @@
 
 #include <ctype.h>
 
+#if defined(__GNUC__) && __GNUC__ >= 7
+#define fallthrough __attribute__((fallthrough));
+#else
+#define fallthrough ;
+#endif
+
 #ifndef WITH_TSC
 
 #define READ_TIMESTAMP(var)
@@ -724,12 +730,14 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 #define TARGET_NOARG(op) \
 		TARGET_##op: \
 		opcode = op; \
+	        fallthrough; \
 		case op:\
 
 #define TARGET(op) \
 		TARGET_##op: \
 		opcode = op; \
 		oparg = NEXTARG(); \
+	        fallthrough; \
 		case op:\
 
 
@@ -2057,6 +2065,9 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
                 /* Fallthrough */
             case 1:
                 w = POP(); /* exc */
+#if defined(__GNUC__) && __GNUC__ >= 7
+		__attribute__ ((fallthrough));
+#endif
             case 0: /* Fallthrough */
                 why = do_raise(w, v, u);
                 break;

Python/compile.c

@@ -3079,12 +3079,18 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
         switch (e->v.Attribute.ctx) {
         case AugLoad:
             ADDOP(c, DUP_TOP);
+#if defined(__GNUC__) && __GNUC__ >= 7
+	     __attribute__ ((fallthrough));
+#endif
             /* Fall through to load */
         case Load:
             ADDOP_NAME(c, LOAD_ATTR, e->v.Attribute.attr, names);
             break;
         case AugStore:
             ADDOP(c, ROT_TWO);
+#if defined(__GNUC__) && __GNUC__ >= 7
+	     __attribute__ ((fallthrough));
+#endif
             /* Fall through to save */
         case Store:
             ADDOP_NAME(c, STORE_ATTR, e->v.Attribute.attr, names);

Python/dtoa.c

@@ -1527,6 +1527,9 @@ _Py_dg_strtod(const char *s00, char **se)
     switch (c) {
     case '-':
         sign = 1;
+#if defined(__GNUC__) && __GNUC__ >= 7
+	 __attribute__ ((fallthrough));
+#endif
         /* no break */
     case '+':
         c = *++s;
@@ -1596,6 +1599,9 @@ _Py_dg_strtod(const char *s00, char **se)
         switch (c) {
         case '-':
             esign = 1;
+#if defined(__GNUC__) && __GNUC__ >= 7
+	     __attribute__ ((fallthrough));
+#endif
             /* no break */
         case '+':
             c = *++s;
@@ -2514,6 +2520,9 @@ _Py_dg_dtoa(double dd, int mode, int ndigits,
         break;
     case 2:
         leftright = 0;
+#if defined(__GNUC__) && __GNUC__ >= 7
+	 __attribute__ ((fallthrough));
+#endif
         /* no break */
     case 4:
         if (ndigits <= 0)
@@ -2522,6 +2531,9 @@ _Py_dg_dtoa(double dd, int mode, int ndigits,
         break;
     case 3:
         leftright = 0;
+#if defined(__GNUC__) && __GNUC__ >= 7
+	 __attribute__ ((fallthrough));
+#endif
         /* no break */
     case 5:
         i = ndigits + k + 1;

Python/getargs.c

@@ -1736,6 +1736,9 @@ skipitem(const char **p_format, va_list *p_va, int flags)
                 /* after 'e', only 's' and 't' is allowed */
                 goto err;
             format++;
+#if defined(__GNUC__) && __GNUC__ >= 7
+	     __attribute__ ((fallthrough));
+#endif
             /* explicit fallthrough to string cases */
         }