Merge pull request #3701 from yang-g/unreachable

mark unreachable code with a macro

include/grpc/support/port_platform.h

@@ -181,6 +181,7 @@
 #ifndef _BSD_SOURCE
 #define _BSD_SOURCE
 #endif
+#define GPR_FORBID_UNREACHABLE_CODE
 #define GPR_MSG_IOVLEN_TYPE int
 #if TARGET_OS_IPHONE
 #define GPR_PLATFORM_STRING "ios"
@@ -336,4 +337,15 @@ typedef uintptr_t gpr_uintptr;
 #endif
 #endif
 
+#ifdef GPR_FORBID_UNREACHABLE_CODE
+#define GPR_UNREACHABLE_CODE(STATEMENT)
+#else
+#define GPR_UNREACHABLE_CODE(STATEMENT)             \
+  do {                                              \
+    gpr_log(GPR_ERROR, "Should never reach here."); \
+    abort();                                        \
+    STATEMENT;                                      \
+  } while (0)
+#endif /* GPR_FORBID_UNREACHABLE_CODE */
+
 #endif /* GRPC_SUPPORT_PORT_PLATFORM_H */

src/core/channel/client_channel.c

@@ -645,9 +645,7 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx,
     case CALL_WAITING_FOR_CONFIG:
     case CALL_WAITING_FOR_CALL:
     case CALL_WAITING_FOR_SEND:
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return );
-      abort();
-      break;
   }
 }
 

src/core/client_config/uri_parser.c

@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
 #include <grpc/support/string_util.h>
 
 /** a size_t default value... maps to all 1's */
@@ -120,8 +121,7 @@ static int parse_fragment_or_query(const char *uri_text, size_t *i) {
         } else {
           return 1;
         }
-        gpr_log(GPR_ERROR, "should never reach here");
+        GPR_UNREACHABLE_CODE(return 0);
-        abort();
       default:
         (*i) += advance;
         break;

src/core/httpcli/parser.c

@@ -139,8 +139,7 @@ static int finish_line(grpc_httpcli_parser *parser) {
       }
       break;
     case GRPC_HTTPCLI_BODY:
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return 0);
-      abort();
   }
 
   parser->cur_line_length = 0;
@@ -165,8 +164,7 @@ static int addbyte(grpc_httpcli_parser *parser, gpr_uint8 byte) {
       } else {
         return 1;
       }
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return 0);
-      abort();
     case GRPC_HTTPCLI_BODY:
       if (parser->r.body_length == parser->body_capacity) {
         parser->body_capacity = GPR_MAX(8, parser->body_capacity * 3 / 2);
@@ -177,10 +175,7 @@ static int addbyte(grpc_httpcli_parser *parser, gpr_uint8 byte) {
       parser->r.body_length++;
       return 1;
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-
-  return 0;
 }
 
 void grpc_httpcli_parser_init(grpc_httpcli_parser *parser) {

src/core/iomgr/tcp_client_posix.c

@@ -191,7 +191,7 @@ static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, int success) {
     goto finish;
   }
 
-  abort();
+  GPR_UNREACHABLE_CODE(return );
 
 finish:
   if (fd != NULL) {

src/core/iomgr/tcp_server_posix.c

@@ -352,7 +352,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, int success) {
     gpr_free(addr_str);
   }
 
-  abort();
+  GPR_UNREACHABLE_CODE(return );
 
 error:
   gpr_mu_lock(&sp->server->mu);

src/core/surface/byte_buffer.c

@@ -75,9 +75,7 @@ grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb) {
       return grpc_raw_byte_buffer_create(bb->data.raw.slice_buffer.slices,
                                          bb->data.raw.slice_buffer.count);
   }
-  gpr_log(GPR_INFO, "should never get here");
+  GPR_UNREACHABLE_CODE(return NULL);
-  abort();
-  return NULL;
 }
 
 void grpc_byte_buffer_destroy(grpc_byte_buffer *bb) {
@@ -95,7 +93,5 @@ size_t grpc_byte_buffer_length(grpc_byte_buffer *bb) {
     case GRPC_BB_RAW:
       return bb->data.raw.slice_buffer.length;
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-  return 0;
 }

src/core/surface/call.c

@@ -434,8 +434,7 @@ static grpc_cq_completion *allocate_completion(grpc_call *call) {
     gpr_mu_unlock(&call->completion_mu);
     return &call->completions[i];
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return NULL);
-  abort();
   return NULL;
 }
 

src/core/surface/channel_connectivity.c

@@ -100,9 +100,7 @@ static void finished_completion(grpc_exec_ctx *exec_ctx, void *pw,
   switch (w->phase) {
     case WAITING:
     case CALLED_BACK:
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return );
-      abort();
-      break;
     case CALLING_BACK:
       w->phase = CALLED_BACK;
       break;
@@ -149,9 +147,7 @@ static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
       w->phase = CALLING_BACK_AND_FINISHED;
       break;
     case CALLING_BACK_AND_FINISHED:
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return );
-      abort();
-      break;
     case CALLED_BACK:
       delete = 1;
       break;

src/core/surface/completion_queue.c

@@ -254,8 +254,7 @@ static void del_plucker(grpc_completion_queue *cc, void *tag,
       return;
     }
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return );
-  abort();
 }
 
 grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,

src/core/transport/chttp2/frame_data.c

@@ -168,7 +168,5 @@ grpc_chttp2_parse_error grpc_chttp2_data_parser_parse(
       }
   }
 
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return GRPC_CHTTP2_CONNECTION_ERROR);
-  abort();
-  return GRPC_CHTTP2_CONNECTION_ERROR;
 }

src/core/transport/chttp2/frame_goaway.c

@@ -152,9 +152,7 @@ grpc_chttp2_parse_error grpc_chttp2_goaway_parser_parse(
       }
       return GRPC_CHTTP2_PARSE_OK;
   }
-  gpr_log(GPR_ERROR, "Should never end up here");
+  GPR_UNREACHABLE_CODE(return GRPC_CHTTP2_CONNECTION_ERROR);
-  abort();
-  return GRPC_CHTTP2_CONNECTION_ERROR;
 }
 
 void grpc_chttp2_goaway_append(gpr_uint32 last_stream_id, gpr_uint32 error_code,

src/core/transport/chttp2/hpack_parser.c

@@ -1166,9 +1166,7 @@ static int append_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
       append_bytes(str, decoded, 3);
       goto b64_byte0;
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 1);
-  abort();
-  return 1;
 }
 
 /* append a null terminator to a string */
@@ -1313,9 +1311,7 @@ static int parse_value_string(grpc_chttp2_hpack_parser *p, const gpr_uint8 *cur,
       return 0;
   }
   /* Add code to prevent return without value error */
-  gpr_log(GPR_ERROR, "Should never reach beyond switch in parse_value_string");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-  return 0;
 }
 
 static int parse_value_string_with_indexed_key(grpc_chttp2_hpack_parser *p,

src/core/transport/chttp2/parsing.c

@@ -417,14 +417,10 @@ int grpc_chttp2_perform_read(grpc_exec_ctx *exec_ctx,
         transport_parsing->incoming_frame_size -= (gpr_uint32)(end - cur);
         return 1;
       }
-      gpr_log(GPR_ERROR, "should never reach here");
+      GPR_UNREACHABLE_CODE(return 0);
-      abort();
   }
 
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-
-  return 0;
 }
 
 static int init_frame_parser(grpc_chttp2_transport_parsing *transport_parsing) {
@@ -580,9 +576,7 @@ static int init_data_frame_parser(
     case GRPC_CHTTP2_CONNECTION_ERROR:
       return 0;
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-  return 0;
 }
 
 static void free_timeout(void *p) { gpr_free(p); }
@@ -820,7 +814,5 @@ static int parse_frame_slice(grpc_exec_ctx *exec_ctx,
     case GRPC_CHTTP2_CONNECTION_ERROR:
       return 0;
   }
-  gpr_log(GPR_ERROR, "should never reach here");
+  GPR_UNREACHABLE_CODE(return 0);
-  abort();
-  return 0;
 }

src/core/transport/chttp2/stream_encoder.c

@@ -428,7 +428,7 @@ static grpc_mdelem *hpack_enc(grpc_chttp2_hpack_compressor *c,
       emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
       return elem;
     }
-    abort();
+    GPR_UNREACHABLE_CODE(return NULL);
   }
 
   indices_key = c->indices_keys[HASH_FRAGMENT_3(key_hash)];
@@ -442,7 +442,7 @@ static grpc_mdelem *hpack_enc(grpc_chttp2_hpack_compressor *c,
       emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
       return elem;
     }
-    abort();
+    GPR_UNREACHABLE_CODE(return NULL);
   }
 
   /* no elem, key in the table... fall back to literal emission */
@@ -454,7 +454,7 @@ static grpc_mdelem *hpack_enc(grpc_chttp2_hpack_compressor *c,
     emit_lithdr_noidx_v(c, elem, st);
     return elem;
   }
-  abort();
+  GPR_UNREACHABLE_CODE(return NULL);
 }
 
 #define STRLEN_LIT(x) (sizeof(x) - 1)

src/cpp/server/server.cc

@@ -153,8 +153,7 @@ class Server::SyncRequest GRPC_FINAL : public CompletionQueueTag {
         GPR_ASSERT((*req)->in_flight_);
         return true;
     }
-    gpr_log(GPR_ERROR, "Should never reach here");
+    GPR_UNREACHABLE_CODE(return false);
-    abort();
   }
 
   void SetupRequest() { cq_ = grpc_completion_queue_create(nullptr); }