Fixed all known static analysis bugs, with checker-279 on macOS.

src/libm/e_rem_pio2.c

@@ -24,6 +24,8 @@ static const char rcsid[] =
 #include "math_libm.h"
 #include "math_private.h"
 
+#include "SDL_assert.h"
+
 libm_hidden_proto(fabs)
 
 /*
@@ -189,7 +191,12 @@ __ieee754_rem_pio2(x, y)
     }
     tx[2] = z;
     nx = 3;
-    while (tx[nx - 1] == zero)
+
+    /* If this assertion ever fires, here's the static analysis that warned about it:
+        http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-8c6ccb.html#EndPath */
+    SDL_assert((tx[0] != zero) || (tx[1] != zero) || (tx[2] != zero));
+
+    while (nx && tx[nx - 1] == zero)
         nx--;                   /* skip zero term */
     n = __kernel_rem_pio2(tx, y, e0, nx, 2, two_over_pi);
     if (hx < 0) {

src/libm/k_rem_pio2.c

@@ -204,8 +204,13 @@ __kernel_rem_pio2(x, y, e0, nx, prec, ipio2)
 
     /* compute q[0],q[1],...q[jk] */
     for (i = 0; i <= jk; i++) {
-        for (j = 0, fw = 0.0; j <= jx; j++)
-            fw += x[j] * f[jx + i - j];
+        for (j = 0, fw = 0.0; j <= jx; j++) {
+            const int32_t idx = jx + i - j;
+            SDL_assert(idx >= 0);
+            SDL_assert(idx < 20);
+            SDL_assert(idx <= m);
+            fw += x[j] * f[idx];
+        }
         q[i] = fw;
     }
 

src/render/SDL_render.c

@@ -734,8 +734,8 @@ SDL_UpdateTextureYUV(SDL_Texture * texture, const SDL_Rect * rect,
 
     if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
         /* We can lock the texture and copy to it */
-        void *native_pixels;
-        int native_pitch;
+        void *native_pixels = NULL;
+        int native_pitch = 0;
 
         if (SDL_LockTexture(native, rect, &native_pixels, &native_pitch) < 0) {
             return -1;
@@ -745,18 +745,18 @@ SDL_UpdateTextureYUV(SDL_Texture * texture, const SDL_Rect * rect,
         SDL_UnlockTexture(native);
     } else {
         /* Use a temporary buffer for updating */
-        void *temp_pixels;
-        int temp_pitch;
-
-        temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
-        temp_pixels = SDL_malloc(rect->h * temp_pitch);
-        if (!temp_pixels) {
-            return SDL_OutOfMemory();
+        const int temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
+        const size_t alloclen = rect->h * temp_pitch;
+        if (alloclen > 0) {
+            void *temp_pixels = SDL_malloc(alloclen);
+            if (!temp_pixels) {
+                return SDL_OutOfMemory();
+            }
+            SDL_SW_CopyYUVToRGB(texture->yuv, rect, native->format,
+                                rect->w, rect->h, temp_pixels, temp_pitch);
+            SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
+            SDL_free(temp_pixels);
         }
-        SDL_SW_CopyYUVToRGB(texture->yuv, rect, native->format,
-                            rect->w, rect->h, temp_pixels, temp_pitch);
-        SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
-        SDL_free(temp_pixels);
     }
     return 0;
 }
@@ -767,10 +767,14 @@ SDL_UpdateTextureNative(SDL_Texture * texture, const SDL_Rect * rect,
 {
     SDL_Texture *native = texture->native;
 
+    if (!rect->w || !rect->h) {
+        return 0;  /* nothing to do. */
+    }
+
     if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
         /* We can lock the texture and copy to it */
-        void *native_pixels;
-        int native_pitch;
+        void *native_pixels = NULL;
+        int native_pitch = 0;
 
         if (SDL_LockTexture(native, rect, &native_pixels, &native_pitch) < 0) {
             return -1;
@@ -781,19 +785,19 @@ SDL_UpdateTextureNative(SDL_Texture * texture, const SDL_Rect * rect,
         SDL_UnlockTexture(native);
     } else {
         /* Use a temporary buffer for updating */
-        void *temp_pixels;
-        int temp_pitch;
-
-        temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
-        temp_pixels = SDL_malloc(rect->h * temp_pitch);
-        if (!temp_pixels) {
-            return SDL_OutOfMemory();
+        const int temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
+        const size_t alloclen = rect->h * temp_pitch;
+        if (alloclen > 0) {
+            void *temp_pixels = SDL_malloc(alloclen);
+            if (!temp_pixels) {
+                return SDL_OutOfMemory();
+            }
+            SDL_ConvertPixels(rect->w, rect->h,
+                              texture->format, pixels, pitch,
+                              native->format, temp_pixels, temp_pitch);
+            SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
+            SDL_free(temp_pixels);
         }
-        SDL_ConvertPixels(rect->w, rect->h,
-                          texture->format, pixels, pitch,
-                          native->format, temp_pixels, temp_pitch);
-        SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
-        SDL_free(temp_pixels);
     }
     return 0;
 }
@@ -853,10 +857,14 @@ SDL_UpdateTextureYUVPlanar(SDL_Texture * texture, const SDL_Rect * rect,
     full_rect.h = texture->h;
     rect = &full_rect;
 
+    if (!rect->w || !rect->h) {
+        return 0;  /* nothing to do. */
+    }
+
     if (texture->access == SDL_TEXTUREACCESS_STREAMING) {
         /* We can lock the texture and copy to it */
-        void *native_pixels;
-        int native_pitch;
+        void *native_pixels = NULL;
+        int native_pitch = 0;
 
         if (SDL_LockTexture(native, rect, &native_pixels, &native_pitch) < 0) {
             return -1;
@@ -866,18 +874,18 @@ SDL_UpdateTextureYUVPlanar(SDL_Texture * texture, const SDL_Rect * rect,
         SDL_UnlockTexture(native);
     } else {
         /* Use a temporary buffer for updating */
-        void *temp_pixels;
-        int temp_pitch;
-
-        temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
-        temp_pixels = SDL_malloc(rect->h * temp_pitch);
-        if (!temp_pixels) {
-            return SDL_OutOfMemory();
+        const int temp_pitch = (((rect->w * SDL_BYTESPERPIXEL(native->format)) + 3) & ~3);
+        const size_t alloclen = rect->h * temp_pitch;
+        if (alloclen > 0) {
+            void *temp_pixels = SDL_malloc(alloclen);
+            if (!temp_pixels) {
+                return SDL_OutOfMemory();
+            }
+            SDL_SW_CopyYUVToRGB(texture->yuv, rect, native->format,
+                                rect->w, rect->h, temp_pixels, temp_pitch);
+            SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
+            SDL_free(temp_pixels);
         }
-        SDL_SW_CopyYUVToRGB(texture->yuv, rect, native->format,
-                            rect->w, rect->h, temp_pixels, temp_pitch);
-        SDL_UpdateTexture(native, rect, temp_pixels, temp_pitch);
-        SDL_free(temp_pixels);
     }
     return 0;
 }
@@ -924,6 +932,10 @@ int SDL_UpdateYUVTexture(SDL_Texture * texture, const SDL_Rect * rect,
         rect = &full_rect;
     }
 
+    if (!rect->w || !rect->h) {
+        return 0;  /* nothing to do. */
+    }
+
     if (texture->yuv) {
         return SDL_UpdateTextureYUVPlanar(texture, rect, Yplane, Ypitch, Uplane, Upitch, Vplane, Vpitch);
     } else {
@@ -1882,6 +1894,24 @@ SDL_RenderPresent(SDL_Renderer * renderer)
     renderer->RenderPresent(renderer);
 }
 
+/* this isn't responsible for removing the deleted texture from the list!
+   (this is to keep static analysis happy in SDL_DestroyRenderer().) */
+static void
+SDL_DestroyTextureInternal(SDL_Texture * texture)
+{
+    SDL_Renderer *renderer = texture->renderer;
+    if (texture->native) {
+        SDL_DestroyTexture(texture->native);
+    }
+    if (texture->yuv) {
+        SDL_SW_DestroyYUVTexture(texture->yuv);
+    }
+    SDL_free(texture->pixels);
+
+    renderer->DestroyTexture(renderer, texture);
+    SDL_free(texture);
+}
+
 void
 SDL_DestroyTexture(SDL_Texture * texture)
 {
@@ -1894,7 +1924,7 @@ SDL_DestroyTexture(SDL_Texture * texture)
         SDL_SetRenderTarget(renderer, NULL);
     }
 
-    texture->magic = NULL;
+    texture->magic = NULL;  /* just in case, but we're about to free this... */
 
     if (texture->next) {
         texture->next->prev = texture->prev;
@@ -1905,29 +1935,27 @@ SDL_DestroyTexture(SDL_Texture * texture)
         renderer->textures = texture->next;
     }
 
-    if (texture->native) {
-        SDL_DestroyTexture(texture->native);
-    }
-    if (texture->yuv) {
-        SDL_SW_DestroyYUVTexture(texture->yuv);
-    }
-    SDL_free(texture->pixels);
-
-    renderer->DestroyTexture(renderer, texture);
-    SDL_free(texture);
+    SDL_DestroyTextureInternal(texture);
 }
 
 void
 SDL_DestroyRenderer(SDL_Renderer * renderer)
 {
+    SDL_Texture *texture = NULL;
+    SDL_Texture *nexttexture = NULL;
+
     CHECK_RENDERER_MAGIC(renderer, );
 
     SDL_DelEventWatch(SDL_RendererEventWatch, renderer);
 
     /* Free existing textures for this renderer */
-    while (renderer->textures) {
-        SDL_DestroyTexture(renderer->textures);
+    SDL_SetRenderTarget(renderer, NULL);
+
+    for (texture = renderer->textures; texture; texture = nexttexture) {
+        nexttexture = texture->next;
+        SDL_DestroyTexture(texture);
     }
+    renderer->textures = NULL;
 
     if (renderer->window) {
         SDL_SetWindowData(renderer->window, SDL_WINDOWRENDERDATA, NULL);

src/render/SDL_yuv_sw.c

@@ -875,14 +875,16 @@ number_of_bits_set(Uint32 a)
  * Low performance, do not call often.
  */
 static int
+free_bits_at_bottom_nonzero(Uint32 a)
+{
+    SDL_assert(a != 0);
+    return (((Sint32) a) & 1l) ? 0 : 1 + free_bits_at_bottom_nonzero(a >> 1);
+}
+
+static SDL_INLINE int
 free_bits_at_bottom(Uint32 a)
 {
-    /* assume char is 8 bits */
-    if (!a)
-        return sizeof(Uint32) * 8;
-    if (((Sint32) a) & 1l)
-        return 0;
-    return 1 + free_bits_at_bottom(a >> 1);
+    return a ? free_bits_at_bottom_nonzero(a) : 32;
 }
 
 static int
@@ -894,6 +896,7 @@ SDL_SW_SetupYUVDisplay(SDL_SW_YUVTexture * swdata, Uint32 target_format)
     int i;
     int bpp;
     Uint32 Rmask, Gmask, Bmask, Amask;
+    int freebits;
 
     if (!SDL_PixelFormatEnumToMasks
         (target_format, &bpp, &Rmask, &Gmask, &Bmask, &Amask) || bpp < 15) {
@@ -910,13 +913,24 @@ SDL_SW_SetupYUVDisplay(SDL_SW_YUVTexture * swdata, Uint32 target_format)
      */
     for (i = 0; i < 256; ++i) {
         r_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Rmask));
-        r_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Rmask);
+        freebits = free_bits_at_bottom(Rmask);
+        if (freebits < 32) {
+            r_2_pix_alloc[i + 256] <<= freebits;
+        }
         r_2_pix_alloc[i + 256] |= Amask;
+
         g_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Gmask));
-        g_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Gmask);
+        freebits = free_bits_at_bottom(Gmask);
+        if (freebits < 32) {
+            g_2_pix_alloc[i + 256] <<= freebits;
+        }
         g_2_pix_alloc[i + 256] |= Amask;
+
         b_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Bmask));
-        b_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Bmask);
+        freebits = free_bits_at_bottom(Bmask);
+        if (freebits < 32) {
+            b_2_pix_alloc[i + 256] <<= freebits;
+        }
         b_2_pix_alloc[i + 256] |= Amask;
     }
 

src/render/opengl/SDL_render_gl.c

@@ -1430,18 +1430,21 @@ GL_RenderReadPixels(SDL_Renderer * renderer, const SDL_Rect * rect,
 
     GL_ActivateRenderer(renderer);
 
+    if (!convert_format(data, temp_format, &internalFormat, &format, &type)) {
+        return SDL_SetError("Texture format %s not supported by OpenGL",
+                            SDL_GetPixelFormatName(temp_format));
+    }
+
+    if (!rect->w || !rect->h) {
+        return 0;  /* nothing to do. */
+    }
+
     temp_pitch = rect->w * SDL_BYTESPERPIXEL(temp_format);
     temp_pixels = SDL_malloc(rect->h * temp_pitch);
     if (!temp_pixels) {
         return SDL_OutOfMemory();
     }
 
-    if (!convert_format(data, temp_format, &internalFormat, &format, &type)) {
-        SDL_free(temp_pixels);
-        return SDL_SetError("Texture format %s not supported by OpenGL",
-                            SDL_GetPixelFormatName(temp_format));
-    }
-
     SDL_GetRendererOutputSize(renderer, &w, &h);
 
     data->glPixelStorei(GL_PACK_ALIGNMENT, 1);

src/video/SDL_RLEaccel.c

@@ -1277,7 +1277,7 @@ RLEColorkeySurface(SDL_Surface * surface)
     int y;
     Uint8 *srcbuf, *lastline;
     int maxsize = 0;
-    int bpp = surface->format->BytesPerPixel;
+    const int bpp = surface->format->BytesPerPixel;
     getpix_func getpix;
     Uint32 ckey, rgbmask;
     int w, h;
@@ -1300,6 +1300,9 @@ RLEColorkeySurface(SDL_Surface * surface)
         maxsize = surface->h * (4 * (surface->w / 65535 + 1)
                                 + surface->w * 4) + 4;
         break;
+
+    default:
+        return -1;
     }
 
     rlebuf = (Uint8 *) SDL_malloc(maxsize);
@@ -1393,7 +1396,7 @@ RLEColorkeySurface(SDL_Surface * surface)
         surface->map->data = p;
     }
 
-    return (0);
+    return 0;
 }
 
 int

src/video/SDL_rect.c

@@ -22,7 +22,7 @@
 
 #include "SDL_rect.h"
 #include "SDL_rect_c.h"
-
+#include "SDL_assert.h"
 
 SDL_bool
 SDL_HasIntersection(const SDL_Rect * A, const SDL_Rect * B)
@@ -441,9 +441,15 @@ SDL_IntersectRectAndLine(const SDL_Rect * rect, int *X1, int *Y1, int *X2,
                 y = recty2;
                 x = x1 + ((x2 - x1) * (y - y1)) / (y2 - y1);
             } else if (outcode2 & CODE_LEFT) {
+                /* If this assertion ever fires, here's the static analysis that warned about it:
+                   http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-b0d01a.html#EndPath */
+                SDL_assert(x2 != x1);  /* if equal: division by zero. */
                 x = rectx1;
                 y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
             } else if (outcode2 & CODE_RIGHT) {
+                /* If this assertion ever fires, here's the static analysis that warned about it:
+                   http://buildbot.libsdl.org/sdl-static-analysis/sdl-macosx-static-analysis/sdl-macosx-static-analysis-1101/report-39b114.html#EndPath */
+                SDL_assert(x2 != x1);  /* if equal: division by zero. */
                 x = rectx2;
                 y = y1 + ((y2 - y1) * (x - x1)) / (x2 - x1);
             }

src/video/SDL_video.c

@@ -338,9 +338,14 @@ SDL_CreateWindowTexture(SDL_VideoDevice *unused, SDL_Window * window, Uint32 * f
     /* Create framebuffer data */
     data->bytes_per_pixel = SDL_BYTESPERPIXEL(*format);
     data->pitch = (((window->w * data->bytes_per_pixel) + 3) & ~3);
-    data->pixels = SDL_malloc(window->h * data->pitch);
-    if (!data->pixels) {
-        return SDL_OutOfMemory();
+
+    {
+        /* Make static analysis happy about potential malloc(0) calls. */
+        const size_t allocsize = window->h * data->pitch;
+        data->pixels = SDL_malloc((allocsize > 0) ? allocsize : 1);
+        if (!data->pixels) {
+            return SDL_OutOfMemory();
+        }
     }
 
     *pixels = data->pixels;