# [PATCH v2 0/3] Fix LLP64 `(size_t)1` compatibility VS C4334 warnings 6 messages from 2021-12-01 to 2021-12-02. Participants: Philip Oakley, Junio C Hamano, Derrick Stolee. Thread: https://gitlist.dev/t/57006 ## Philip Oakley, 2021-12-01 00:28 Subject: [PATCH v2 0/3] Fix LLP64 `(size_t)1` compatibility VS C4334 warnings Message-ID: <20211201002902.1042-1-philipoakley@iee.email> URL: https://gitlist.dev/e/20211201002902.1042-1-philipoakley%40iee.email ``` Since V1 (gitster/po/size-t-for-vs) https://lore.kernel.org/git/20211126113614.709-1-philipoakley@iee.email/ Former patch 1/4 was dropped as it was already in Junio's tree. Patch 1/3 corrects my spelling mistake. Patch 2/3 has added extra spacing around the << operator as suggested by Stollee[1]. Patch 3/3 removes the superceded commit message comment regarding backporting the patch onto maint. The Visual Studio MSVC compilation reports a number of C4334 "was 64-bit shift intended" size mismatch warnings. In most of these cases a size_t is ANDed (masked) with a bit shift of 1, or 1U. On LLP64 systems the unity value is 32 bits, while size_t is 64 bits. The fix is to upcast the unity value to size_t. The first [dropped] patch had been reported [2] by René Scharfe as an extra patch to the rs/mergesort series. These fixes clear all the current C4334 warnings. [1] https://lore.kernel.org/git/?q=%3Cf721bc99-6d79-e2f2-7810-dd77b777161f%40gmail.com%3E [2] https://lore.kernel.org/git/7fbd4cf4-5f66-a4cd-0c41-e5b12d14d761@iee.email/ Philip Oakley (3): repack.c: LLP64 compatibility, upcast unity for left shift diffcore-delta.c: LLP64 compatibility, upcast unity for left shift object-file.c: LLP64 compatibility, upcast unity for left shift builtin/repack.c | 2 +- diffcore-delta.c | 6 +++--- object-file.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) Range-diff against v1: 1: c00e082ed8 < -: ---------- mergesort.c: LLP64 compatibility, upcast unity for left shift 2: 85506c7e77 ! 1: 13d9b3fd6d repack.c: LLP64 compatibility, upcast unity for left shift @@ Commit message repack.c: LLP64 compatibility, upcast unity for left shift Visual Studio reports C4334 "was 64-bit shift intended" warning - because of size miss-match. + because of size mismatch. Promote unity to the matching type to fit with the `&` operator. 3: 2072852f61 ! 2: b6c7ad9177 diffcore-delta.c: LLP64 compatibility, upcast unity for left shift @@ diffcore-delta.c: static struct spanhash_top *hash_chars(struct repository *r, i = INITIAL_HASH_SIZE; hash = xmalloc(st_add(sizeof(*hash), - st_mult(sizeof(struct spanhash), 1<alloc_log2 = i; hash->free = INITIAL_FREE(i); - memset(hash->data, 0, sizeof(struct spanhash) * (1< - --- - - This cannot be applied to the maint-2.32 branch as the earlier René Scharfe - patch had been, because the original sha1-file.c, to which the backport - would apply, has been renamed in e5afd4449d (object-file.c: rename - from sha1-file.c, 2020-12-31) which was merged in 8b327f1784 - (Merge branch 'ma/sha1-is-a-hash', 2021-01-15) - ## object-file.c ## @@ object-file.c: struct oidtree *odb_loose_cache(struct object_directory *odb, struct strbuf buf = STRBUF_INIT; -- 2.34.0.rc1.windows.1.4.ga126985b17 ``` ## Philip Oakley, 2021-12-01 00:29 Subject: [PATCH v2 1/3] repack.c: LLP64 compatibility, upcast unity for left shift Message-ID: <20211201002902.1042-2-philipoakley@iee.email> URL: https://gitlist.dev/e/20211201002902.1042-2-philipoakley%40iee.email In-Reply-To: <20211201002902.1042-1-philipoakley@iee.email> ``` Visual Studio reports C4334 "was 64-bit shift intended" warning because of size mismatch. Promote unity to the matching type to fit with the `&` operator. Signed-off-by: Philip Oakley --- builtin/repack.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/builtin/repack.c b/builtin/repack.c index 0b2d1e5d82..6da66474fd 100644 --- a/builtin/repack.c +++ b/builtin/repack.c @@ -842,7 +842,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix) fname_old = mkpathdup("%s-%s%s", packtmp, item->string, exts[ext].name); - if (((uintptr_t)item->util) & (1 << ext)) { + if (((uintptr_t)item->util) & ((uintptr_t)1 << ext)) { struct stat statbuffer; if (!stat(fname_old, &statbuffer)) { statbuffer.st_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH); -- 2.34.0.rc1.windows.1.4.ga126985b17 ``` ## Philip Oakley, 2021-12-01 00:29 Subject: [PATCH v2 2/3] diffcore-delta.c: LLP64 compatibility, upcast unity for left shift Message-ID: <20211201002902.1042-3-philipoakley@iee.email> URL: https://gitlist.dev/e/20211201002902.1042-3-philipoakley%40iee.email In-Reply-To: <20211201002902.1042-1-philipoakley@iee.email> ``` Visual Studio reports C4334 "was 64-bit shift intended" warning because of size miss-match. Promote unity to the matching type to fit with its subsequent operation. Signed-off-by: Philip Oakley --- diffcore-delta.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/diffcore-delta.c b/diffcore-delta.c index 5668ace60d..18d8f766d7 100644 --- a/diffcore-delta.c +++ b/diffcore-delta.c @@ -133,10 +133,10 @@ static struct spanhash_top *hash_chars(struct repository *r, i = INITIAL_HASH_SIZE; hash = xmalloc(st_add(sizeof(*hash), - st_mult(sizeof(struct spanhash), 1<alloc_log2 = i; hash->free = INITIAL_FREE(i); - memset(hash->data, 0, sizeof(struct spanhash) * (1<data, 0, sizeof(struct spanhash) * ((size_t)1 << i)); n = 0; accum1 = accum2 = 0; @@ -159,7 +159,7 @@ static struct spanhash_top *hash_chars(struct repository *r, n = 0; accum1 = accum2 = 0; } - QSORT(hash->data, 1ul << hash->alloc_log2, spanhash_cmp); + QSORT(hash->data, (size_t)1ul << hash->alloc_log2, spanhash_cmp); return hash; } -- 2.34.0.rc1.windows.1.4.ga126985b17 ``` ## Philip Oakley, 2021-12-01 00:29 Subject: [PATCH v2 3/3] object-file.c: LLP64 compatibility, upcast unity for left shift Message-ID: <20211201002902.1042-4-philipoakley@iee.email> URL: https://gitlist.dev/e/20211201002902.1042-4-philipoakley%40iee.email In-Reply-To: <20211201002902.1042-1-philipoakley@iee.email> ``` Visual Studio reports C4334 "was 64-bit shift intended" warning because of size miss-match. Promote unity to the matching type to fit with the assignment. Signed-off-by: Philip Oakley --- object-file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/object-file.c b/object-file.c index c3d866a287..da8821cb91 100644 --- a/object-file.c +++ b/object-file.c @@ -2425,7 +2425,7 @@ struct oidtree *odb_loose_cache(struct object_directory *odb, struct strbuf buf = STRBUF_INIT; size_t word_bits = bitsizeof(odb->loose_objects_subdir_seen[0]); size_t word_index = subdir_nr / word_bits; - size_t mask = 1u << (subdir_nr % word_bits); + size_t mask = (size_t)1u << (subdir_nr % word_bits); uint32_t *bitmap; if (subdir_nr < 0 || -- 2.34.0.rc1.windows.1.4.ga126985b17 ``` ## Junio C Hamano, 2021-12-01 22:49 Subject: Re: [PATCH v2 0/3] Fix LLP64 `(size_t)1` compatibility VS C4334 warnings Message-ID: URL: https://gitlist.dev/e/xmqq5ys8ym8s.fsf%40gitster.g In-Reply-To: <20211201002902.1042-1-philipoakley@iee.email> ``` Philip Oakley writes: > Since V1 (gitster/po/size-t-for-vs) > https://lore.kernel.org/git/20211126113614.709-1-philipoakley@iee.email/ > > Former patch 1/4 was dropped as it was already in Junio's tree. > > Patch 1/3 corrects my spelling mistake. > > Patch 2/3 has added extra spacing around the << operator as suggested by > Stollee[1]. > > Patch 3/3 removes the superceded commit message comment regarding > backporting the patch onto maint. > > The Visual Studio MSVC compilation reports a number of C4334 "was 64-bit > shift intended" size mismatch warnings. In most of these cases a size_t > is ANDed (masked) with a bit shift of 1, or 1U. On LLP64 systems the unity > value is 32 bits, while size_t is 64 bits. > > The fix is to upcast the unity value to size_t. > > The first [dropped] patch had been reported [2] by René Scharfe as an extra patch > to the rs/mergesort series. > > These fixes clear all the current C4334 warnings. Thanks. Will queue; let's have it in 'next'. ``` ## Derrick Stolee, 2021-12-02 20:56 Subject: Re: [PATCH v2 0/3] Fix LLP64 `(size_t)1` compatibility VS C4334 warnings Message-ID: URL: https://gitlist.dev/e/cbcdcad7-16c5-b14d-5edc-5c91909b13e2%40gmail.com In-Reply-To: ``` On 12/1/2021 5:49 PM, Junio C Hamano wrote: > Philip Oakley writes: > >> Since V1 (gitster/po/size-t-for-vs) >> https://lore.kernel.org/git/20211126113614.709-1-philipoakley@iee.email/ >> >> Former patch 1/4 was dropped as it was already in Junio's tree. >> >> Patch 1/3 corrects my spelling mistake. >> >> Patch 2/3 has added extra spacing around the << operator as suggested by >> Stollee[1]. >> >> Patch 3/3 removes the superceded commit message comment regarding >> backporting the patch onto maint. >> >> The Visual Studio MSVC compilation reports a number of C4334 "was 64-bit >> shift intended" size mismatch warnings. In most of these cases a size_t >> is ANDed (masked) with a bit shift of 1, or 1U. On LLP64 systems the unity >> value is 32 bits, while size_t is 64 bits. >> >> The fix is to upcast the unity value to size_t. >> >> The first [dropped] patch had been reported [2] by René Scharfe as an extra patch >> to the rs/mergesort series. >> >> These fixes clear all the current C4334 warnings. > > Thanks. Will queue; let's have it in 'next'. I agree. This version is excellent. -Stolee ```