On Thu, Jan 31, 2019 at 12:30 PM Gustavo A. R. Silva <gust...@embeddedor.com> wrote: > > > > On 1/30/19 1:58 AM, Kees Cook wrote: > > On Wed, Jan 30, 2019 at 12:34 PM Gustavo A. R. Silva > > <gust...@embeddedor.com> wrote: > >> > >> In preparation to enabling -Wimplicit-fallthrough, mark switch > >> cases where we are expecting to fall through. > >> > >> This patch fixes the following warnings: > >> > >> lib/zstd/bitstream.h:261:30: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/bitstream.h:262:30: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/bitstream.h:263:30: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/bitstream.h:264:30: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/bitstream.h:265:30: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/compress.c:3183:16: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/decompress.c:1770:18: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/decompress.c:2376:15: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/decompress.c:2404:15: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/decompress.c:2435:16: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> lib/zstd/huf_compress.c: In function ‘HUF_compress1X_usingCTable’: > >> lib/zstd/huf_compress.c:535:5: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 4 + 7) \ > >> ^ > >> lib/zstd/huf_compress.c:558:54: note: in expansion of macro > >> ‘HUF_FLUSHBITS_2’ > >> case 3: HUF_encodeSymbol(&bitC, ip[n + 2], CTable); > >> HUF_FLUSHBITS_2(&bitC); > >> ^~~~~~~~~~~~~~~ > >> lib/zstd/huf_compress.c:559:2: note: here > >> case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); > >> HUF_FLUSHBITS_1(&bitC); > >> ^~~~ > >> lib/zstd/huf_compress.c:531:5: warning: this statement may fall through > >> [-Wimplicit-fallthrough=] > >> if (sizeof((stream)->bitContainer) * 8 < HUF_TABLELOG_MAX * 2 + 7) \ > >> ^ > >> lib/zstd/huf_compress.c:559:54: note: in expansion of macro > >> ‘HUF_FLUSHBITS_1’ > >> case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); > >> HUF_FLUSHBITS_1(&bitC); > >> ^~~~~~~~~~~~~~~ > >> lib/zstd/huf_compress.c:560:2: note: here > >> case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); HUF_FLUSHBITS(&bitC); > >> ^~~~ > >> AR lib/zstd//built-in.a > >> > >> Warning level 3 was used: -Wimplicit-fallthrough=3 > >> > >> This patch is part of the ongoing efforts to enabling > >> -Wimplicit-fallthrough. > >> > >> Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com> > >> --- > >> lib/zstd/bitstream.h | 5 +++++ > >> lib/zstd/compress.c | 1 + > >> lib/zstd/decompress.c | 5 ++++- > >> lib/zstd/huf_compress.c | 2 ++ > >> 4 files changed, 12 insertions(+), 1 deletion(-) > >> > >> diff --git a/lib/zstd/bitstream.h b/lib/zstd/bitstream.h > >> index a826b99e1d63..3a49784d5c61 100644 > >> --- a/lib/zstd/bitstream.h > >> +++ b/lib/zstd/bitstream.h > >> @@ -259,10 +259,15 @@ ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t > >> *bitD, const void *srcBuffer, s > >> bitD->bitContainer = *(const BYTE *)(bitD->start); > >> switch (srcSize) { > >> case 7: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[6]) << (sizeof(bitD->bitContainer) * 8 - 16); > >> + /* fall through */ > >> case 6: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24); > >> + /* fall through */ > >> case 5: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32); > >> + /* fall through */ > >> case 4: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[3]) << 24; > >> + /* fall through */ > >> case 3: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[2]) << 16; > >> + /* fall through */ > >> case 2: bitD->bitContainer += (size_t)(((const BYTE > >> *)(srcBuffer))[1]) << 8; > >> default:; > >> } > >> diff --git a/lib/zstd/compress.c b/lib/zstd/compress.c > >> index f9166cf4f7a9..5e0b67003e55 100644 > >> --- a/lib/zstd/compress.c > >> +++ b/lib/zstd/compress.c > >> @@ -3182,6 +3182,7 @@ static size_t > >> ZSTD_compressStream_generic(ZSTD_CStream *zcs, void *dst, size_t * > >> zcs->outBuffFlushedSize = 0; > >> zcs->stage = zcss_flush; /* pass-through > >> to flush stage */ > >> } > >> + /* fall through */ > > > > Perhaps reword the existing comment and move it down? > > > >> > >> case zcss_flush: { > >> size_t const toFlush = zcs->outBuffContentSize - > >> zcs->outBuffFlushedSize; > >> diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c > >> index b17846725ca0..269ee9a796c1 100644 > >> --- a/lib/zstd/decompress.c > >> +++ b/lib/zstd/decompress.c > >> @@ -1768,6 +1768,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void > >> *dst, size_t dstCapacity, c > >> return 0; > >> } > >> dctx->expected = 0; /* not necessary to copy more */ > >> + /* fall through */ > >> > >> case ZSTDds_decodeFrameHeader: > >> memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, > >> src, dctx->expected); > >> @@ -2375,7 +2376,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, > >> ZSTD_outBuffer *output, ZSTD_inB > >> } > >> zds->stage = zdss_read; > >> } > >> - /* pass-through */ > >> + /* fall through */ > >> > >> case zdss_read: { > >> size_t const neededInSize = > >> ZSTD_nextSrcSizeToDecompress(zds->dctx); > >> @@ -2404,6 +2405,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, > >> ZSTD_outBuffer *output, ZSTD_inB > >> zds->stage = zdss_load; > >> /* pass-through */ > >> } > >> + /* fall through */ > > > > Same ("pass-through" exists a couple lines up) > > > >> > >> case zdss_load: { > >> size_t const neededInSize = > >> ZSTD_nextSrcSizeToDecompress(zds->dctx); > >> @@ -2436,6 +2438,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, > >> ZSTD_outBuffer *output, ZSTD_inB > >> /* pass-through */ > >> } > >> } > >> + /* fall through */ > > > > Same > > Yeah. The thing is that the pass-though comment is embedded in two nested > blocks of code. And GCC triggers > a warning if the fall-through comments are not placed at the very bottom of > the case statement (some people > dislike this 'feature'). > > That's the reason why I didn't want to change any of the pass-through > comments, and instead added the > fall-through comments at the bottom of every case.
Okay, that seems fine. Good as-is, then! :) -Kees > > What do you think about this 'feature'? > > > > >> > >> case zdss_flush: { > >> size_t const toFlushSize = zds->outEnd - > >> zds->outStart; > >> diff --git a/lib/zstd/huf_compress.c b/lib/zstd/huf_compress.c > >> index 40055a7016e6..e727812d12aa 100644 > >> --- a/lib/zstd/huf_compress.c > >> +++ b/lib/zstd/huf_compress.c > >> @@ -556,7 +556,9 @@ size_t HUF_compress1X_usingCTable(void *dst, size_t > >> dstSize, const void *src, si > >> n = srcSize & ~3; /* join to mod 4 */ > >> switch (srcSize & 3) { > >> case 3: HUF_encodeSymbol(&bitC, ip[n + 2], CTable); > >> HUF_FLUSHBITS_2(&bitC); > >> + /* fall through */ > >> case 2: HUF_encodeSymbol(&bitC, ip[n + 1], CTable); > >> HUF_FLUSHBITS_1(&bitC); > >> + /* fall through */ > >> case 1: HUF_encodeSymbol(&bitC, ip[n + 0], CTable); > >> HUF_FLUSHBITS(&bitC); > >> case 0: > >> default:; > >> -- > >> 2.20.1 > >> > > > > Otherwise, yup, looks good. > > > > Reviewed-by: Kees Cook <keesc...@chromium.org> > > > > Thanks > > -- > Gustavo -- Kees Cook