| Ticket UUID: | 1cc44617e2b4ed0a29f75762d45fe46388260f74 | ||
| Title: | Mechanism with 64 bit support in tcl.h does not work outside of core | ||
| Type: | Bug | Created on: | 2017-03-23 19:04:49 |
| Submitter: | anonymous | Assigned to: | jan.nijtmans |
| Subsystem: | 69. Other | Severity: | Important |
| Priority: | 5 Medium | Last modified: | 2017-03-24 17:33:14 |
| Status: | Open | Closed by: | nobody |
| Resolution: | Works For Me | Closed on: | |
| Version: | 8.6/8.7 | ||
| Description: | ||||
|
For 64 bit support in tcl.h the following constants will be used: TCL_WIDE_INT_TYPE (on 32 bit arch) or TCL_WIDE_INT_IS_LONG (on 64 bit arch). With Mac the following (stripped) code seems to work: #ifdef __APPLE__ # ifdef __LP64__ # undef TCL_WIDE_INT_TYPE # define TCL_WIDE_INT_IS_LONG 1 # else /* !__LP64__ */ # define TCL_WIDE_INT_TYPE long long # undef TCL_WIDE_INT_IS_LONG # endif /* __LP64__ */ #endif /* __APPLE__ */For Windows/Linux/UNIX it cannot work properly, see this annotated code snippet: #if !defined(TCL_WIDE_INT_TYPE)&&!defined(TCL_WIDE_INT_IS_LONG)* /***************************************************************** This is the case when compiling outside of Tcl core, because none of these constants is pre-defined. Mac is excluded here, because handled above. *******************************************************************/ # if defined(_WIN32) /****************************************************************** This branch will be reached when compiling under Windows, even when compiling with any other compiler than MSVC. Now TCL_WIDE_INT_TYPE will be defined even on 64 bit architectures, but due to documentation on 64 bit architectures the constant TCL_WIDE_INT_IS_LONG should be defined instead. Note that on 64 bit machines the constant _WIN32 is also pre-defined. Also note that the definition of TCL_WIDE_INT_TYPE is probably incorrect when compiling with an other compiler than MSVC. *******************************************************************/ # define TCL_WIDE_INT_TYPE __int64 # ifdef __BORLANDC__ # define TCL_LL_MODIFIER "L" # else /* __BORLANDC__ */ # define TCL_LL_MODIFIER "I64" # endif /* __BORLANDC__ */ # elif defined(__GNUC__) /****************************************************************** This is the case when compiling with gcc under Linux/UNIX. Now TCL_WIDE_INT_TYPE will be defined, whether 32 bit or 64 bit architecture, but due to documentation on 64 bit architectures the constant TCL_WIDE_INT_IS_LONG should be defined instead. And the definition of TCL_LL_MODIFIER is incorrect on 64 bit architectures, should be "l" instead. *******************************************************************/ # define TCL_WIDE_INT_TYPE long long # define TCL_LL_MODIFIER "ll" # else /* ! _WIN32 && ! __GNUC__ */ # ... # endif /* _WIN32 */ #endif /* !TCL_WIDE_INT_TYPE & !TCL_WIDE_INT_IS_LONG */A technical note: for me it seems to be more logical to change the order for __GCC__ and _WIN32, because the __GCC__ branch works in any case, whether Windows or not: #if defined(__GCC__) # ... #elif defined(_WIN32) # ... #endifAt this place I suggest to use the opportunity for modernizing the definitions of 64 bit support based on C99, see this example:
#if HAVE_STDINT_H
# include <stdint.h>
#elif defined(_MSC_VER) && _MSC_VER < 1600
/* work around for the support of ancient compilers */
# include "tkWinStdInt.h"
#else
/* this is not expected with compilers from this century, except MSVC (handled above) */
# error "C99 support is required - can't include stdint.h"
#endif
typedef int64_t Tcl_WideInt;
typedef uint64_t Tcl_WideUInt;
#if HAVE_STDINT_H
# if (UINTPTR_MAX == 0xffffffffu)
# define TCL_IS_32_BIT_ARCH
# elif (UINTPTR_MAX >= 0xffffffffffffffffu)
/* We handle >64 bit also as 64 bit architectures. */
# define TCL_IS_64_BIT_ARCH
# else
# error "unsupported architecture" /* can never happen */
# endif
#elif defined(_WIN64) /* ancient compiler support */
# define TCL_IS_64_BIT_ARCH
#elif defined(_WIN32) /* ancient compiler support */
# define TCL_IS_32_BIT_ARCH
#else
# error "cannot detect architecture" /* can never happen */
#endif /* HAVE_STDINT_H */
#if TCL_IS_64_BIT_ARCH
# define Tcl_WideAsLong(val) ((long)(val))
...
#else /* if TCL_IS_32_BIT_ARCH */
# define Tcl_WideAsLong(val) ((long)((Tcl_WideInt)(val)))
...
#endif /* TCL_IS_64_BIT_ARCH */
#if defined(_MSC_VER) /* only MSVC (Windows) */
# define TCL_LL_MODIFIER "I64"
#elif defined(TCL_IS_64_BIT_ARCH)
# define TCL_LL_MODIFIER "l"
#else /* if TCL_IS_32_BIT_ARCH */
# define TCL_LL_MODIFIER "ll"
#endif /* _WIN32 */
...
For file tkWinStdInt.h see repository of Tk project revised_text. Note that every compiler of these days is supplying the header files <stdint.h> and <inttypes.h> (belongs to C99). The ancient compiler support (old MSVC versions) is only for ActiveState (they don't have enough money for a newer compiler?). Please note that the Tk developers would benefit with the modern definitions, because in this project <stdint.h> will be used, and also the differentiation between 32 and 64 bit architectures is important for Tk. | ||||
| User Comments: | ||||
jan.nijtmans added on 2017-03-24 13:35:48:
So, if it (as you claim) doesn't work outside of the core, the best thing to do is create a test-case. Committed here: dd4d4f822dd767de This test-case works fine on any platform I know. So, what's wrong with this test-case? Why does it work despite you claiming that it doesn't work? Sure, the 64-bit support could be improved, the current macro organization is not really 'transparant'. But - still - I fail to see the bug here. In my view, TCL_LL_MODIFIER should be "I64" on Win32/Win64 (any compiler, including gcc), "l" on LP64 systems, "ll" on any other system. TCL_WIDE_INT_TYPE should be __int64 on Win32/Win64 (any compiler, including gcc), long on LP64 systems, and long long on any other system. What am I missing? anonymous added on 2017-03-24 15:02:56:
I don't have a 64 bit architecture, so I cannot test. On my 32 bit machine indeed the mechanism works. But I refer to verbal statements:
gcc -DTCL_WIDE_INT_IS_LONG=1- is it possible that in your test environment the makefile contains this definition?. Outside of Tcl core, when TCL_WIDE_INT_IS_LONG is not predefined, the mechanism cannot work. If you remove -DTCL_WIDE_INT_IS_LONG=1, what happens now? If it works although you have removed -DTCL_WIDE_INT_IS_LONG=1, in which line of tcl.h the correct setup (TCL_WIDE_INT_IS_LONG=1) will be done? jan.nijtmans added on 2017-03-24 16:03:01:
Well, I think you misunderstand the intention of TCL_WIDE_INT_IS_LONG. On Win64, sizeof(long) == 4 and sizeof(void *) == 8. So, although pointers are 64-bit, long is 32-bit. So it is correct that on Win32/Win64, TCL_WIDE_INT_IS_LONG is NOT defined. That's as expected! TCL_WIDE_INT_IS_LONG doesn't tell anything about the platform being 32-bit or 64-bit. It just tells whether "long" is 32-bit or 64-bit. Not really what you expect, isn't it? In your analysis, you expect TCL_WIDE_INT_IS_LONG to be set on Win64. Well, that's incorrect, and that's where your analysis is wrong. Sorry ;-) anonymous added on 2017-03-24 17:33:14:
Yes, I trapped into a pitfall because of this comment in tcl.h: * TCL_WIDE_INT_IS_LONG - if wide ints are really longs (i.e. we're on a real * 64-bit system.)This comment "we're on a real 64-bit system" is misleading. That's why I've used this constant for testing whether it's a 64 bit machine. But probably I didn't understand the term "real" here. BTW: And this shows that a modernization is more clear, because in C99 you can simply use: typedef uint64_t Tcl_WideInt; #define TCL_LL_MODIFIER __PRI64_PREFIX But of course here the name TCL_LL_MODIFIER is not useful anymore, should be TCL_WIDE_INT_MODIFIER. | ||||