Changeset 73097 in vbox for trunk/include/iprt

Timestamp:

Jul 12, 2018 9:06:33 PM (7 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

123672

Message:

*: Made RT_UOFFSETOF, RT_OFFSETOF, RT_UOFFSETOF_ADD and RT_OFFSETOF_ADD work like builtin_offsetof() and require compile time resolvable requests, adding RT_UOFFSETOF_DYN for the dynamic questions that can only be answered at runtime.

Location:

trunk/include/iprt

Files:

• cdefs.h (modified) (3 diffs)
• nt/nt.h (modified) (1 diff)

trunk/include/iprt/cdefs.h

@@ -2265 +2265 @@
  * Our own special offsetof() variant, returns a signed result.
  *
- * This differs from the usual offsetof() in that it's not relying on builtin
- * compiler stuff and thus can use variables in arrays the structure may
- * contain. This is useful to determine the sizes of structures ending
- * with a variable length field. For gcc >= 4.4 see @bugref{7775}.
- *
  * @returns offset into the structure of the specified member. signed.
  * @param   type    Structure type.
  * @param   member  Member.
- */
-#if defined(__cplusplus) && RT_GNUC_PREREQ(4, 4)
-# define RT_OFFSETOF(type, member)              ( (int)(uintptr_t)&( ((type *)(void *)0x1000)->member) - 0x1000 )
-#else
-# define RT_OFFSETOF(type, member)              ( (int)(uintptr_t)&( ((type *)(void *)0)->member) )
+ *
+ * @remarks Only use this for static offset calculations. Please
+ *          use RT_UOFFSETOF_DYN for dynamic ones (i.e. involves
+ *          non-constant array indexing).
+ *
+ */
+#if RT_GNUC_PREREQ(4, 0)
+# define RT_OFFSETOF(type, member)              ( (int)__builtin_offsetof(type, member) )
+#else
+# define RT_OFFSETOF(type, member)              ( (int)(intptr_t)&( ((type *)(void *)0)->member) )
 #endif
 
 /** @def RT_UOFFSETOF
- * Our own special offsetof() variant, returns an unsigned result.
- *
- * This differs from the usual offsetof() in that it's not relying on builtin
- * compiler stuff and thus can use variables in arrays the structure may
- * contain. This is useful to determine the sizes of structures ending
- * with a variable length field. For gcc >= 4.4 see @bugref{7775}.
+ * Our own offsetof() variant, returns an unsigned result.
  *
  * @returns offset into the structure of the specified member. unsigned.
  * @param   type    Structure type.
  * @param   member  Member.
- */
-#if defined(__cplusplus) && RT_GNUC_PREREQ(4, 4)
-# define RT_UOFFSETOF(type, member)             ( (uintptr_t)&( ((type *)(void *)0x1000)->member) - 0x1000 )
+ *
+ * @remarks Only use this for static offset calculations. Please
+ *          use RT_UOFFSETOF_DYN for dynamic ones (i.e. involves
+ *          non-constant array indexing).
+ */
+#if RT_GNUC_PREREQ(4, 0)
+# define RT_UOFFSETOF(type, member)             ( (uintptr_t)__builtin_offsetof(type, member) )
 #else
 # define RT_UOFFSETOF(type, member)             ( (uintptr_t)&( ((type *)(void *)0)->member) )
@@ -2305 +2304 @@
  * @param   member  Member.
  * @param   addend  The addend to add to the offset.
+ *
+ * @remarks Only use this for static offset calculations.
  */
 #define RT_OFFSETOF_ADD(type, member, addend)   ( (int)RT_UOFFSETOF_ADD(type, member, addend) )
@@ -2315 +2316 @@
  * @param   member  Member.
  * @param   addend  The addend to add to the offset.
- */
-#define RT_UOFFSETOF_ADD(type, member, addend)  ( (uintptr_t)&( ((type *)(void *)(uintptr_t)(addend))->member) )
+ *
+ * @remarks Only use this for static offset calculations.
+ */
+#if RT_GNUC_PREREQ(4, 0)
+# define RT_UOFFSETOF_ADD(type, member, addend)  ( (uintptr_t)(__builtin_offsetof(type, member) + (addend)))
+#else
+# define RT_UOFFSETOF_ADD(type, member, addend)  ( (uintptr_t)&( ((type *)(void *)(uintptr_t)(addend))->member) )
+#endif
+
+/** @def RT_UOFFSETOF_DYN
+ * Dynamic (runtime) structure offset calculations, involving
+ * indexing of array members via variable.
+ *
+ * @returns offset into the structure of the specified member. signed.
+ * @param   type        Structure type.
+ * @param   memberarray Member.
+ */
+#if defined(__cplusplus) && RT_GNUC_PREREQ(4, 4)
+# define RT_UOFFSETOF_DYN(type, memberarray)    ( (uintptr_t)&( ((type *)(void *)0x1000)->memberarray) - 0x1000 )
+#else
+# define RT_UOFFSETOF_DYN(type, memberarray)    ( (uintptr_t)&( ((type *)(void *)0)->memberarray) )
+#endif
+
 
 /** @def RT_SIZEOFMEMB

trunk/include/iprt/nt/nt.h

@@ -1494 +1494 @@
 #if !defined(NtCurrentTeb) && !defined(IPRT_NT_HAVE_CURRENT_TEB_MACRO)
 # ifdef RT_ARCH_X86
-DECL_FORCE_INLINE(PTEB)     RTNtCurrentTeb(void) { return (PTEB)__readfsdword(RT_OFFSETOF(TEB_COMMON, NtTib.Self)); }
-DECL_FORCE_INLINE(PPEB)     RTNtCurrentPeb(void) { return (PPEB)__readfsdword(RT_OFFSETOF(TEB_COMMON, ProcessEnvironmentBlock)); }
-DECL_FORCE_INLINE(uint32_t) RTNtCurrentThreadId(void) { return __readfsdword(RT_OFFSETOF(TEB_COMMON, ClientId.UniqueThread)); }
-DECL_FORCE_INLINE(NTSTATUS) RTNtLastStatusValue(void) { return (NTSTATUS)__readfsdword(RT_OFFSETOF(TEB_COMMON, LastStatusValue)); }
-DECL_FORCE_INLINE(uint32_t) RTNtLastErrorValue(void)  { return __readfsdword(RT_OFFSETOF(TEB_COMMON, LastErrorValue)); }
+DECL_FORCE_INLINE(PTEB)     RTNtCurrentTeb(void) { return (PTEB)__readfsdword(RT_UOFFSETOF(TEB_COMMON, NtTib.Self)); }
+DECL_FORCE_INLINE(PPEB)     RTNtCurrentPeb(void) { return (PPEB)__readfsdword(RT_UOFFSETOF(TEB_COMMON, ProcessEnvironmentBlock)); }
+DECL_FORCE_INLINE(uint32_t) RTNtCurrentThreadId(void) { return __readfsdword(RT_UOFFSETOF(TEB_COMMON, ClientId.UniqueThread)); }
+DECL_FORCE_INLINE(NTSTATUS) RTNtLastStatusValue(void) { return (NTSTATUS)__readfsdword(RT_UOFFSETOF(TEB_COMMON, LastStatusValue)); }
+DECL_FORCE_INLINE(uint32_t) RTNtLastErrorValue(void)  { return __readfsdword(RT_UOFFSETOF(TEB_COMMON, LastErrorValue)); }
 # elif defined(RT_ARCH_AMD64)
-DECL_FORCE_INLINE(PTEB)     RTNtCurrentTeb(void) { return (PTEB)__readgsqword(RT_OFFSETOF(TEB_COMMON, NtTib.Self)); }
-DECL_FORCE_INLINE(PPEB)     RTNtCurrentPeb(void) { return (PPEB)__readgsqword(RT_OFFSETOF(TEB_COMMON, ProcessEnvironmentBlock)); }
-DECL_FORCE_INLINE(uint32_t) RTNtCurrentThreadId(void) { return __readgsdword(RT_OFFSETOF(TEB_COMMON, ClientId.UniqueThread)); }
-DECL_FORCE_INLINE(NTSTATUS) RTNtLastStatusValue(void) { return (NTSTATUS)__readgsdword(RT_OFFSETOF(TEB_COMMON, LastStatusValue)); }
-DECL_FORCE_INLINE(uint32_t) RTNtLastErrorValue(void)  { return __readgsdword(RT_OFFSETOF(TEB_COMMON, LastErrorValue)); }
+DECL_FORCE_INLINE(PTEB)     RTNtCurrentTeb(void) { return (PTEB)__readgsqword(RT_UOFFSETOF(TEB_COMMON, NtTib.Self)); }
+DECL_FORCE_INLINE(PPEB)     RTNtCurrentPeb(void) { return (PPEB)__readgsqword(RT_UOFFSETOF(TEB_COMMON, ProcessEnvironmentBlock)); }
+DECL_FORCE_INLINE(uint32_t) RTNtCurrentThreadId(void) { return __readgsdword(RT_UOFFSETOF(TEB_COMMON, ClientId.UniqueThread)); }
+DECL_FORCE_INLINE(NTSTATUS) RTNtLastStatusValue(void) { return (NTSTATUS)__readgsdword(RT_UOFFSETOF(TEB_COMMON, LastStatusValue)); }
+DECL_FORCE_INLINE(uint32_t) RTNtLastErrorValue(void)  { return __readgsdword(RT_UOFFSETOF(TEB_COMMON, LastErrorValue)); }
 # else
 #  error "Port me"