* [PATCH] lib: zstd: Mark expected switch fall-throughs
@ 2019-01-29 23:34 Gustavo A. R. Silva
2019-01-30 7:58 ` Kees Cook
0 siblings, 1 reply; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-29 23:34 UTC (permalink / raw)
To: linux-kernel; +Cc: Gustavo A. R. Silva, Kees Cook
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 <gustavo@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 */
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 */
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 */
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] lib: zstd: Mark expected switch fall-throughs
2019-01-29 23:34 [PATCH] lib: zstd: Mark expected switch fall-throughs Gustavo A. R. Silva
@ 2019-01-30 7:58 ` Kees Cook
2019-01-30 23:30 ` Gustavo A. R. Silva
0 siblings, 1 reply; 4+ messages in thread
From: Kees Cook @ 2019-01-30 7:58 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: LKML
On Wed, Jan 30, 2019 at 12:34 PM Gustavo A. R. Silva
<gustavo@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 <gustavo@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
>
> 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 <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] lib: zstd: Mark expected switch fall-throughs
2019-01-30 7:58 ` Kees Cook
@ 2019-01-30 23:30 ` Gustavo A. R. Silva
2019-01-31 5:49 ` Kees Cook
0 siblings, 1 reply; 4+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-30 23:30 UTC (permalink / raw)
To: Kees Cook; +Cc: LKML
On 1/30/19 1:58 AM, Kees Cook wrote:
> On Wed, Jan 30, 2019 at 12:34 PM Gustavo A. R. Silva
> <gustavo@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 <gustavo@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.
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 <keescook@chromium.org>
>
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] lib: zstd: Mark expected switch fall-throughs
2019-01-30 23:30 ` Gustavo A. R. Silva
@ 2019-01-31 5:49 ` Kees Cook
0 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2019-01-31 5:49 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: LKML
On Thu, Jan 31, 2019 at 12:30 PM Gustavo A. R. Silva
<gustavo@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
> > <gustavo@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 <gustavo@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 <keescook@chromium.org>
> >
>
> Thanks
>
> --
> Gustavo
--
Kees Cook
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2019-01-29 23:34 [PATCH] lib: zstd: Mark expected switch fall-throughs Gustavo A. R. Silva
2019-01-30 7:58 ` Kees Cook
2019-01-30 23:30 ` Gustavo A. R. Silva
2019-01-31 5:49 ` Kees Cook
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