cmd/cgo: C.size_t issues on Xcode 5 #6506
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I can see how calloc, and probably realloc too, are less important. But I think that if these 3 are the only ones that need this sort of fix, it's still worth it, mostly to keep existing code from failing. Now, if you tell me that there are like 5 other functions that have the same problem, then yes, it becomes somewhat pointless to fix them. But if it's limited to these 3, why not go for it? |
Considering issue #6575 (the same issue, with memcpy) I don't think adding more wrappers is the right solution after all. |
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Issue #6575 has been merged into this issue. |
@dominik.honnef, i installed LLVM 3.3 + Clang 3.3 from source on my Gentoo machine, but ./all.bash failed to reproduce the problem, the only failure is: # ../misc/cgo/testcdefs # _/home/minux/go/go.hg/misc/cgo/testcdefs ./cdefstest.h:13 ./cdefstest.c:6 array size must be a positive constant ./cdefstest.h:15 ./cdefstest.c:6 array size must be a positive constant ./cdefstest.h:17 ./cdefstest.c:6 array size must be a positive constant |
As for clang 3.3 and all.bash: There is no problem that all.bash could reproduce. The issue with malloc was fixed in issue #5926 with a wrapper and Go/the standard library do not use calloc or realloc or any other function that has the size_t/ulong issue themselves and doesn't have any tests for that, either. The problem will only manifest with user written code that uses cgo and for example calloc or realloc with size_t arguments. The reason I think this should be addressed somehow, if possible is because it will make old cgo code fail on OS X Mavericks in a confusing way because of a subtle difference in gcc and clang. |
Regarding issue #17: does clang support an option like -gdwarf-3 to select DWARF version 3? Does it support an option like -gstrict-dwarf to restrict DWARF usage to disable DWARF extensions? See also https://golang.org/cl/14669045 to get a bit more information. |
The problem is that clang has a bunch of "builtin" function definitions, and those builtin ones serialize into dwarf using ulong instead of size_t. It only happens for these builtins, not for all functions. So we can special-case the builtins in cmd/cgo. The full set, from clang/Basic/Builtins.def, is LIBBUILTIN(calloc, "v*zz", "f", "stdlib.h", ALL_LANGUAGES) LIBBUILTIN(malloc, "v*z", "f", "stdlib.h", ALL_LANGUAGES) LIBBUILTIN(realloc, "v*v*z", "f", "stdlib.h", ALL_LANGUAGES) LIBBUILTIN(memcpy, "v*v*vC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(memcmp, "ivC*vC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(memmove, "v*v*vC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strncpy, "c*c*cC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strncmp, "icC*cC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strncat, "c*c*cC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strxfrm, "zc*cC*z", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(memchr, "v*vC*iz", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strcspn, "zcC*cC*", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strspn, "zcC*cC*", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(memset, "v*v*iz", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(strlen, "zcC*", "f", "string.h", ALL_LANGUAGES) LIBBUILTIN(snprintf, "ic*zcC*.", "fp:2:", "stdio.h", ALL_LANGUAGES) LIBBUILTIN(vsnprintf, "ic*zcC*a", "fP:2:", "stdio.h", ALL_LANGUAGES) LIBBUILTIN(alloca, "v*z", "f", "stdlib.h", ALL_GNU_LANGUAGES) LIBBUILTIN(stpncpy, "c*c*cC*z", "f", "string.h", ALL_GNU_LANGUAGES) LIBBUILTIN(strndup, "c*cC*z", "f", "string.h", ALL_GNU_LANGUAGES) LIBBUILTIN(bzero, "vv*z", "f", "strings.h", ALL_GNU_LANGUAGES) LIBBUILTIN(strncasecmp, "icC*cC*z", "f", "strings.h", ALL_GNU_LANGUAGES) LIBBUILTIN(strlcpy, "zc*cC*z", "f", "string.h", ALL_GNU_LANGUAGES) LIBBUILTIN(strlcat, "zc*cC*z", "f", "string.h", ALL_GNU_LANGUAGES) Labels changed: added go1.2, removed go1.2maybe. Owner changed to @rsc. Status changed to Started. |
For the record, here is the evidence against clang. The argument inside the memset
prototype (at 0x00000045) is (incorrectly) long unsigned int, while the argument inside
the myfunc prototype (at 0x0000007e) is (correctly) size_t.
g% cat x.c
#include <string.h>
void myfunc(size_t);
typeof(memset) *memset_func;
typeof(myfunc) *myfunc_func;
g% clang -c -gdwarf-2 x.c
g% dwarfdump x.o
----------------------------------------------------------------------
File: x.o (x86_64)
----------------------------------------------------------------------
.debug_info contents:
0x00000000: Compile Unit: length = 0x0000009c version = 0x0002 abbr_offset =
0x00000000 addr_size = 0x08 (next CU at 0x000000a0)
0x0000000b: TAG_compile_unit [1] *
AT_producer( "Apple LLVM version 5.0 (clang-500.2.75) (based on LLVM 3.3svn)" )
AT_language( DW_LANG_C99 )
AT_name( "x.c" )
AT_low_pc( 0x0000000000000000 )
AT_stmt_list( 0x00000000 )
AT_comp_dir( "/Users/rsc/_obj" )
0x00000026: TAG_pointer_type [2]
0x00000027: TAG_base_type [3]
AT_name( "int" )
AT_encoding( DW_ATE_signed )
AT_byte_size( 0x04 )
0x0000002e: TAG_base_type [3]
AT_name( "long unsigned int" )
AT_encoding( DW_ATE_unsigned )
AT_byte_size( 0x08 )
0x00000035: TAG_subroutine_type [4] *
AT_type( {0x00000026} ( * ) )
AT_prototyped( 0x01 )
0x0000003b: TAG_formal_parameter [5]
AT_type( {0x00000026} ( * ) )
0x00000040: TAG_formal_parameter [5]
AT_type( {0x00000027} ( int ) )
0x00000045: TAG_formal_parameter [5]
AT_type( {0x0000002e} ( long unsigned int ) )
0x0000004a: NULL
0x0000004b: TAG_pointer_type [6]
AT_type( {0x00000035} ( function * ) )
0x00000050: TAG_variable [7]
AT_name( "memset_func" )
AT_type( {0x0000004b} ( function ** ) )
AT_external( 0x01 )
AT_decl_file( "/Users/rsc/_obj/x.c" )
AT_decl_line( 5 )
AT_location( [0x0000000000000000] )
0x00000066: TAG_typedef [8]
AT_type( {0x0000002e} ( long unsigned int ) )
AT_name( "__darwin_size_t" )
AT_decl_file( "/Users/rsc/_obj/x.c" )
AT_decl_line( 90 )
0x00000071: TAG_typedef [8]
AT_type( {0x00000066} ( __darwin_size_t ) )
AT_name( "size_t" )
AT_decl_file( "/Users/rsc/_obj/x.c" )
AT_decl_line( 68 )
0x0000007c: TAG_subroutine_type [9] *
AT_prototyped( 0x01 )
0x0000007e: TAG_formal_parameter [5]
AT_type( {0x00000071} ( size_t ) )
0x00000083: NULL
0x00000084: TAG_pointer_type [6]
AT_type( {0x0000007c} ( function ) )
0x00000089: TAG_variable [7]
AT_name( "myfunc_func" )
AT_type( {0x00000084} ( function * ) )
AT_external( 0x01 )
AT_decl_file( "/Users/rsc/_obj/x.c" )
AT_decl_line( 6 )
AT_location( [0x0000000000000000] )
0x0000009f: NULL
g%
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This issue was closed by revision 56aeec3. Status changed to Fixed. |
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Comment 24 by mazdak@chango.com: I see this error trying to do the following on Mavericks:
CC=clang ./all.bash
# ../misc/cgo/test
# _/usr/local/go/misc/cgo/test
./issue6506.go:22:8: error: expected parameter declarator
size_t strlcpy(char*, const char*, size_t);
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:44:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:62:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:30:32:
note: expanded from macro '_USE_FORTIFY_LEVEL'
# define _USE_FORTIFY_LEVEL 2
^
./issue6506.go:22:8: error: expected ')'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:44:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:62:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:30:32:
note: expanded from macro '_USE_FORTIFY_LEVEL'
# define _USE_FORTIFY_LEVEL 2
^
./issue6506.go:22:8: note: to match this '('
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:44:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:53:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
./issue6506.go:22:8: error: type specifier missing, defaults to 'int'
[-Werror,-Wimplicit-int]
size_t strlcpy(char*, const char*, size_t);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:44:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:31:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^~~~~~~~~~~~~~~~~~~~~
./issue6506.go:22:8: error: conflicting types for '__builtin___strlcpy_chk'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:3:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^
./issue6506.go:22:8: note: '__builtin___strlcpy_chk' is a builtin with type 'unsigned
long (char *, const char *, unsigned long, unsigned long)'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:105:3:
note: expanded from macro 'strlcpy'
__builtin___strlcpy_chk (dest, src, len, __darwin_obsz (dest))
^
./issue6506.go:23:8: error: expected parameter declarator
size_t strlcat(char*, const char*, size_t);
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:44:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:62:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:30:32:
note: expanded from macro '_USE_FORTIFY_LEVEL'
# define _USE_FORTIFY_LEVEL 2
^
./issue6506.go:23:8: error: expected ')'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:44:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:62:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:30:32:
note: expanded from macro '_USE_FORTIFY_LEVEL'
# define _USE_FORTIFY_LEVEL 2
^
./issue6506.go:23:8: note: to match this '('
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:44:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:53:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^
./issue6506.go:23:8: error: type specifier missing, defaults to 'int'
[-Werror,-Wimplicit-int]
size_t strlcat(char*, const char*, size_t);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:44:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^~~~~~~~~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_common.h:39:31:
note: expanded from macro '__darwin_obsz'
#define __darwin_obsz(object) __builtin_object_size (object, _USE_FORTIFY_LEVEL > 1 ? 1
: 0)
^~~~~~~~~~~~~~~~~~~~~
./issue6506.go:23:8: error: conflicting types for '__builtin___strlcat_chk'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:3:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^
./issue6506.go:23:8: note: '__builtin___strlcat_chk' is a builtin with type 'unsigned
long (char *, const char *, unsigned long, unsigned long)'
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:3:
note: expanded from macro 'strlcat'
__builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))
^
8 errors generated.
FAIL _/usr/local/go/misc/cgo/test [build failed]
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This issue was closed by revision 4d38d12. |
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by os2nuke:
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