Fix Clang -Wunreachable-code-aggressive warnings

Based on the change in libaom:
fe36011455 Fix Clang -Wunreachable-code-aggressive warnings

Clang's -Wunreachable-code-aggressive flag enables several warning flags
such as -Wunreachable-code-break and -Wunreachable-code-return. Chrome's
build system enables -Wunreachable-code-aggressive (in
build/config/compiler/BUILD.gn), so it would be good if libvpx could be
compiled without -Wunreachable-code-aggressive warnings.

This requires the VPX_NO_RETURN macro be defined correctly for all the
compilers we support, otherwise some compilers may warn about missing
return statements after a die() or fatal() call (which does not return).

Change-Id: I0c069133af45a7a61759538b6d74c681ea087dcd

args.c

@@ -135,7 +135,6 @@ unsigned int arg_parse_uint(const struct arg *arg) {
   }
 
   die("Option %s: Invalid character '%c'\n", arg->name, *endptr);
-  return 0;
 }
 
 int arg_parse_int(const struct arg *arg) {
@@ -152,7 +151,6 @@ int arg_parse_int(const struct arg *arg) {
   }
 
   die("Option %s: Invalid character '%c'\n", arg->name, *endptr);
-  return 0;
 }
 
 struct vpx_rational {
@@ -209,7 +207,6 @@ int arg_parse_enum(const struct arg *arg) {
     if (!strcmp(arg->val, listptr->name)) return listptr->val;
 
   die("Option %s: Invalid value '%s'\n", arg->name, arg->val);
-  return 0;
 }
 
 int arg_parse_enum_or_int(const struct arg *arg) {

configure

@@ -651,7 +651,7 @@ process_toolchain() {
         check_add_cflags -Wmissing-prototypes
         check_add_cflags -Wshadow
         check_add_cflags -Wuninitialized
-        check_add_cflags -Wunreachable-code-loop-increment
+        check_add_cflags -Wunreachable-code-aggressive
         check_add_cflags -Wunused
         check_add_cflags -Wextra
         # check_add_cflags also adds to cxxflags. gtest does not do well with

examples/vp9_spatial_svc_encoder.c

@@ -316,7 +316,6 @@ static void parse_command_line(int argc, const char **argv_,
           break;
         default:
           die("Error: Invalid bit depth selected (%d)\n", enc_cfg->g_bit_depth);
-          break;
       }
 #endif  // CONFIG_VP9_HIGHBITDEPTH
     } else if (arg_match(&arg, &dropframe_thresh_arg, argi)) {

test/partial_idct_test.cc

@@ -76,7 +76,7 @@ class PartialIDctTest : public ::testing::TestWithParam<PartialInvTxfmParam> {
       case TX_8X8: size_ = 8; break;
       case TX_16X16: size_ = 16; break;
       case TX_32X32: size_ = 32; break;
-      default: FAIL() << "Wrong Size!"; break;
+      default: FAIL() << "Wrong Size!";
     }
 
     // Randomize stride_ to a value less than or equal to 1024

test/vp9_ratectrl_rtc_test.cc

@@ -227,7 +227,7 @@ class RcInterfaceSvcTest
         rc_cfg_.layer_target_bitrate[4] = 0;
         rc_cfg_.layer_target_bitrate[5] = 0;
         ASSERT_TRUE(rc_api_->UpdateRateControl(rc_cfg_));
-      } else if (0 && video->frame() == 280) {
+      } else if (/*DISABLES CODE*/ (0) && video->frame() == 280) {
         // TODO(marpan): Re-enable this going back up when issue is fixed.
         // Go back up to 3 spatial layers.
         // Update the encoder config: use the original bitrates.

tools_common.c

@@ -375,7 +375,7 @@ static void highbd_img_upshift(vpx_image_t *dst, vpx_image_t *src,
     case VPX_IMG_FMT_I42216:
     case VPX_IMG_FMT_I44416:
     case VPX_IMG_FMT_I44016: break;
-    default: fatal("Unsupported image conversion"); break;
+    default: fatal("Unsupported image conversion");
   }
   for (plane = 0; plane < 3; plane++) {
     int w = src->d_w;
@@ -411,7 +411,7 @@ static void lowbd_img_upshift(vpx_image_t *dst, vpx_image_t *src,
     case VPX_IMG_FMT_I422:
     case VPX_IMG_FMT_I444:
     case VPX_IMG_FMT_I440: break;
-    default: fatal("Unsupported image conversion"); break;
+    default: fatal("Unsupported image conversion");
   }
   for (plane = 0; plane < 3; plane++) {
     int w = src->d_w;
@@ -452,7 +452,7 @@ void vpx_img_truncate_16_to_8(vpx_image_t *dst, vpx_image_t *src) {
     case VPX_IMG_FMT_I422:
     case VPX_IMG_FMT_I444:
     case VPX_IMG_FMT_I440: break;
-    default: fatal("Unsupported image conversion"); break;
+    default: fatal("Unsupported image conversion");
   }
   for (plane = 0; plane < 3; plane++) {
     int w = src->d_w;
@@ -487,7 +487,7 @@ static void highbd_img_downshift(vpx_image_t *dst, vpx_image_t *src,
     case VPX_IMG_FMT_I42216:
     case VPX_IMG_FMT_I44416:
     case VPX_IMG_FMT_I44016: break;
-    default: fatal("Unsupported image conversion"); break;
+    default: fatal("Unsupported image conversion");
   }
   for (plane = 0; plane < 3; plane++) {
     int w = src->d_w;
@@ -521,7 +521,7 @@ static void lowbd_img_downshift(vpx_image_t *dst, vpx_image_t *src,
     case VPX_IMG_FMT_I422:
     case VPX_IMG_FMT_I444:
     case VPX_IMG_FMT_I440: break;
-    default: fatal("Unsupported image conversion"); break;
+    default: fatal("Unsupported image conversion");
   }
   for (plane = 0; plane < 3; plane++) {
     int w = src->d_w;

vp8/decoder/decodeframe.c

@@ -1167,7 +1167,7 @@ int vp8_decode_frame(VP8D_COMP *pbi) {
   if (pbi->ec_active && xd->corrupted) pc->refresh_last_frame = 1;
 #endif
 
-  if (0) {
+  if (/*DISABLES CODE*/ (0)) {
     FILE *z = fopen("decodestats.stt", "a");
     fprintf(z, "%6d F:%d,G:%d,A:%d,L:%d,Q:%d\n", pc->current_video_frame,
             pc->frame_type, pc->refresh_golden_frame, pc->refresh_alt_ref_frame,

vp8/encoder/firstpass.c

@@ -822,7 +822,7 @@ void vp8_first_pass(VP8_COMP *cpi) {
   }
 
   /* use this to see what the first pass reconstruction looks like */
-  if (0) {
+  if (/*DISABLES CODE*/ (0)) {
     char filename[512];
     FILE *recon_file;
     sprintf(filename, "enc%04d.yuv", (int)cm->current_video_frame);
@@ -1038,7 +1038,7 @@ static int estimate_cq(VP8_COMP *cpi, FIRSTPASS_STATS *fpstats,
   double clip_iifactor;
   int overhead_bits_per_mb;
 
-  if (0) {
+  if (/*DISABLES CODE*/ (0)) {
     FILE *f = fopen("epmp.stt", "a");
     fprintf(f, "%10.2f\n", err_per_mb);
     fclose(f);
@@ -1230,7 +1230,7 @@ static int estimate_kf_group_q(VP8_COMP *cpi, double section_err,
     Q++;
   }
 
-  if (0) {
+  if (/*DISABLES CODE*/ (0)) {
     FILE *f = fopen("estkf_q.stt", "a");
     fprintf(f, "%8d %8d %8d %8.2f %8.3f %8.2f %8.3f %8.3f %8.3f %8d\n",
             cpi->common.current_video_frame, bits_per_mb_at_this_q,
@@ -3047,7 +3047,7 @@ static void find_next_key_frame(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame) {
               (int)((projected_bits_perframe - av_bits_per_frame) *
                     cpi->twopass.frames_to_key));
 
-    if (0) {
+    if (/*DISABLES CODE*/ (0)) {
       FILE *f = fopen("Subsamle.stt", "a");
       fprintf(f, " %8d %8d %8d %8d %12.0f %8d %8d %8d\n",
               cpi->common.current_video_frame, kf_q, cpi->common.horiz_scale,
@@ -3121,7 +3121,7 @@ static void find_next_key_frame(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame) {
         kf_q = estimate_kf_group_q(cpi, err_per_frame * effective_size_ratio,
                                    (int)bits_per_frame, group_iiratio);
 
-        if (0) {
+        if (/*DISABLES CODE*/ (0)) {
           FILE *f = fopen("Subsamle.stt", "a");
           fprintf(
               f, "******** %8d %8d %8d %12.0f %8d %8d %8d\n", kf_q,

vp9/encoder/vp9_ext_ratectrl.c

@@ -131,7 +131,6 @@ static int extrc_get_frame_type(FRAME_UPDATE_TYPE update_type) {
     default:
       fprintf(stderr, "Unsupported update_type %d\n", update_type);
       abort();
-      return 1;
   }
 }
 

vp9/encoder/vp9_firstpass.c

@@ -364,23 +364,20 @@ static vpx_variance_fn_t highbd_get_block_variance_fn(BLOCK_SIZE bsize,
         case BLOCK_8X16: return vpx_highbd_8_mse8x16;
         default: return vpx_highbd_8_mse16x16;
       }
-      break;
     case 10:
       switch (bsize) {
         case BLOCK_8X8: return vpx_highbd_10_mse8x8;
         case BLOCK_16X8: return vpx_highbd_10_mse16x8;
         case BLOCK_8X16: return vpx_highbd_10_mse8x16;
         default: return vpx_highbd_10_mse16x16;
       }
-      break;
     case 12:
       switch (bsize) {
         case BLOCK_8X8: return vpx_highbd_12_mse8x8;
         case BLOCK_16X8: return vpx_highbd_12_mse16x8;
         case BLOCK_8X16: return vpx_highbd_12_mse8x16;
         default: return vpx_highbd_12_mse16x16;
       }
-      break;
   }
 }
 
@@ -1508,7 +1505,7 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
   }
 
   // Use this to see what the first pass reconstruction looks like.
-  if (0) {
+  if (/*DISABLES CODE*/ (0)) {
     char filename[512];
     FILE *recon_file;
     snprintf(filename, sizeof(filename), "enc%04d.yuv",

vp9/encoder/vp9_mbgraph.c

@@ -333,23 +333,16 @@ static void separate_arf_mbs(VP9_COMP *cpi) {
     }
   }
 
-  // Only bother with segmentation if over 10% of the MBs in static segment
-  // if ( ncnt[1] && (ncnt[0] / ncnt[1] < 10) )
-  if (1) {
-    // Note % of blocks that are marked as static
-    if (cm->MBs)
-      cpi->static_mb_pct = (ncnt[1] * 100) / (cm->mi_rows * cm->mi_cols);
-
-    // This error case should not be reachable as this function should
-    // never be called with the common data structure uninitialized.
-    else
-      cpi->static_mb_pct = 0;
-
-    vp9_enable_segmentation(&cm->seg);
-  } else {
+  // Note % of blocks that are marked as static
+  if (cm->MBs)
+    cpi->static_mb_pct = (ncnt[1] * 100) / (cm->mi_rows * cm->mi_cols);
+
+  // This error case should not be reachable as this function should
+  // never be called with the common data structure uninitialized.
+  else
     cpi->static_mb_pct = 0;
-    vp9_disable_segmentation(&cm->seg);
-  }
+
+  vp9_enable_segmentation(&cm->seg);
 
   // Free localy allocated storage
   vpx_free(arf_not_zz);

vp9/simple_encode.cc

@@ -143,7 +143,6 @@ get_frame_type_from_update_type(FRAME_UPDATE_TYPE update_type) {
     default:
       fprintf(stderr, "Unsupported update_type %d\n", update_type);
       abort();
-      return kFrameTypeInter;
   }
 }
 

vpxdec.c

@@ -446,7 +446,7 @@ static void generate_filename(const char *pattern, char *out, size_t q_len,
         case '7': snprintf(q, q_len - 1, "%07d", frame_in); break;
         case '8': snprintf(q, q_len - 1, "%08d", frame_in); break;
         case '9': snprintf(q, q_len - 1, "%09d", frame_in); break;
-        default: die("Unrecognized pattern %%%c\n", p[1]); break;
+        default: die("Unrecognized pattern %%%c\n", p[1]);
       }
 
       pat_len = strlen(q);