From 70df9119f46b334fde6d9b12ec31462b9226a9be Mon Sep 17 00:00:00 2001 From: Ray Molenkamp Date: Wed, 11 Aug 2021 19:20:51 -0600 Subject: Makesdna: Fix detecting 32 bit padding issues. Makesdna fails to detect issues in 32 bit code that can only be resolved by adding a padding pointer. We never noticed since we ourselves no longer build for 32 bit, but debian's 32 bit builds got bitten by this A rather extensive explanation on why this is alignment requirement is there can be found in this comment: https://developer.blender.org/D9389#233034 Differential Revision: https://developer.blender.org/D12188 Reviewed by: sergey, campbellbarton --- source/blender/makesdna/intern/makesdna.c | 69 ++++++++++++++++++++++++++----- 1 file changed, 58 insertions(+), 11 deletions(-) (limited to 'source') diff --git a/source/blender/makesdna/intern/makesdna.c b/source/blender/makesdna/intern/makesdna.c index 85bcc94c335..2ee410efab4 100644 --- a/source/blender/makesdna/intern/makesdna.c +++ b/source/blender/makesdna/intern/makesdna.c @@ -164,6 +164,10 @@ static char **names; static char **types; /** At `types_size[a]` is the size of type `a` on this systems bitness (32 or 64). */ static short *types_size_native; +/** Contains align requirements for a struct on 32 bit systems. */ +static short *types_align_32; +/** Contains align requirements for a struct on 64 bit systems. */ +static short *types_align_64; /** Contains sizes as they are calculated on 32 bit systems. */ static short *types_size_32; /** Contains sizes as they are calculated on 64 bit systems. */ @@ -374,6 +378,8 @@ static int add_type(const char *str, int size) types_size_native[index] = size; types_size_32[index] = size; types_size_64[index] = size; + types_align_32[index] = size; + types_align_64[index] = size; } return index; } @@ -387,7 +393,8 @@ static int add_type(const char *str, int size) types_size_native[types_len] = size; types_size_32[types_len] = size; types_size_64[types_len] = size; - + types_align_32[types_len] = size; + types_align_64[types_len] = size; if (types_len >= max_array_len) { printf("too many types\n"); return types_len - 1; @@ -926,7 +933,9 @@ static int calculate_struct_sizes(int firststruct, FILE *file_verify, const char int size_native = 0; int size_32 = 0; int size_64 = 0; - bool has_pointer = false; + /* Sizes of the largest field in a struct. */ + int max_align_32 = 0; + int max_align_64 = 0; /* check all elements in struct */ for (int b = 0; b < structpoin[1]; b++, sp += 2) { @@ -955,7 +964,6 @@ static int calculate_struct_sizes(int firststruct, FILE *file_verify, const char /* is it a pointer or function pointer? */ if (cp[0] == '*' || cp[1] == '*') { - has_pointer = 1; /* has the name an extra length? (array) */ int mul = 1; if (cp[namelen - 1] == ']') { @@ -1002,6 +1010,8 @@ static int calculate_struct_sizes(int firststruct, FILE *file_verify, const char size_native += sizeof(void *) * mul; size_32 += 4 * mul; size_64 += 8 * mul; + max_align_32 = MAX2(max_align_32, 4); + max_align_64 = MAX2(max_align_64, 8); } else if (cp[0] == '[') { /* parsing can cause names "var" and "[3]" @@ -1047,6 +1057,8 @@ static int calculate_struct_sizes(int firststruct, FILE *file_verify, const char size_native += mul * types_size_native[type]; size_32 += mul * types_size_32[type]; size_64 += mul * types_size_64[type]; + max_align_32 = MAX2(max_align_32, types_align_32[type]); + max_align_64 = MAX2(max_align_64, types_align_64[type]); } else { size_native = 0; @@ -1063,16 +1075,42 @@ static int calculate_struct_sizes(int firststruct, FILE *file_verify, const char types_size_native[structtype] = size_native; types_size_32[structtype] = size_32; types_size_64[structtype] = size_64; - /* Two ways to detect if a struct contains a pointer: - * has_pointer is set or size_native doesn't match any of 32/64bit lengths. */ - if (has_pointer || size_64 != size_native || size_32 != size_native) { - if (size_64 % 8) { + types_align_32[structtype] = max_align_32; + types_align_64[structtype] = max_align_64; + + /* Santiy check 1: alignment should never be 0. */ + BLI_assert(max_align_32); + BLI_assert(max_align_64); + + /* Santiy check 2: alignment should always be equal or smaller than the maximum + * size of a build in type which is 8 bytes (ie int64_t or double). */ + BLI_assert(max_align_32 <= 8); + BLI_assert(max_align_64 <= 8); + + if (size_32 % max_align_32) { + /* There is an one odd case where only the 32 bit struct has alignment issues + * and the 64 bit does not, that can only be fixed by adding a padding pointer + * to the struct to resolve the problem. */ + if ((size_64 % max_align_64 == 0) && (size_32 % max_align_32 == 4)) { fprintf(stderr, - "Sizeerror 8 in struct: %s (add %d bytes)\n", + "Sizeerror in 32 bit struct: %s (add paddding pointer)\n", + types[structtype]); + } + else { + fprintf(stderr, + "Sizeerror in 32 bit struct: %s (add %d bytes)\n", types[structtype], - size_64 % 8); - dna_error = 1; + max_align_32 - (size_32 % max_align_32)); } + dna_error = 1; + } + + if (size_64 % max_align_64) { + fprintf(stderr, + "Sizeerror in 64 bit struct: %s (add %d bytes)\n", + types[structtype], + max_align_64 - (size_64 % max_align_64)); + dna_error = 1; } if (size_native % 4 && !ELEM(size_native, 1, 2)) { @@ -1189,6 +1227,9 @@ static int make_structDNA(const char *base_directory, types_size_native = MEM_callocN(sizeof(short) * max_array_len, "types_size_native"); types_size_32 = MEM_callocN(sizeof(short) * max_array_len, "types_size_32"); types_size_64 = MEM_callocN(sizeof(short) * max_array_len, "types_size_64"); + types_align_32 = MEM_callocN(sizeof(short) * max_array_len, "types_size_32"); + types_align_64 = MEM_callocN(sizeof(short) * max_array_len, "types_size_64"); + structs = MEM_callocN(sizeof(short *) * max_array_len, "structs"); /* Build versioning data */ @@ -1277,7 +1318,11 @@ static int make_structDNA(const char *base_directory, sp += 2; /* ? num_types was elem? */ for (b = 0; b < num_types; b++, sp += 2) { - printf(" %s %s\n", types[sp[0]], names[sp[1]]); + printf(" %s %s allign32:%d, allign64:%d\n", + types[sp[0]], + names[sp[1]], + types_align_32[sp[0]], + types_align_64[sp[0]]); } } } @@ -1399,6 +1444,8 @@ static int make_structDNA(const char *base_directory, MEM_freeN(types_size_native); MEM_freeN(types_size_32); MEM_freeN(types_size_64); + MEM_freeN(types_align_32); + MEM_freeN(types_align_64); MEM_freeN(structs); BLI_memarena_free(mem_arena); -- cgit v1.2.3