Hi,
This is an independently useful patch that makes it easier to introduce
gcc_stablesort.
Swap responsibilities of gcc_qsort and qsort_chk: call the checking function
from the sorting function instead of wrapping gcc_qsort with qsort_chk.
* gcc/sort.cc (gcc_qsort) [CHECKING_P]: Call qsort_chk.
* gcc/system.h (qsort): Always redirect to gcc_qsort. Update comment.
* gcc/vec.c (qsort_chk): Do not call gcc_qsort. Update comment.
diff --git a/gcc/sort.cc b/gcc/sort.cc
index 293e2058f89..9f8ee12e13b 100644
--- a/gcc/sort.cc
+++ b/gcc/sort.cc
@@ -229,4 +229,7 @@ gcc_qsort (void *vbase, size_t n, size_t size, cmp_fn *cmp)
mergesort (base, &c, n, base, (char *)buf);
if (buf != scratch)
free (buf);
+#if CHECKING_P
+ qsort_chk (vbase, n, size, cmp);
+#endif
}
diff --git a/gcc/system.h b/gcc/system.h
index f87fbaae69e..203c6a4f0cf 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -1197,17 +1197,13 @@ helper_const_non_const_cast (const char *p)
/* Get definitions of HOST_WIDE_INT. */
#include "hwint.h"
-/* qsort comparator consistency checking: except in release-checking compilers,
- redirect 4-argument qsort calls to qsort_chk; keep 1-argument invocations
+/* GCC qsort API-compatible functions: except in release-checking compilers,
+ redirect 4-argument qsort calls to gcc_qsort; keep 1-argument invocations
corresponding to vec::qsort (cmp): they use C qsort internally anyway. */
void qsort_chk (void *, size_t, size_t, int (*)(const void *, const void *));
void gcc_qsort (void *, size_t, size_t, int (*)(const void *, const void *));
#define PP_5th(a1, a2, a3, a4, a5, ...) a5
#undef qsort
-#if CHECKING_P
-#define qsort(...) PP_5th (__VA_ARGS__, qsort_chk, 3, 2, qsort, 0)
(__VA_ARGS__)
-#else
#define qsort(...) PP_5th (__VA_ARGS__, gcc_qsort, 3, 2, qsort, 0)
(__VA_ARGS__)
-#endif
#endif /* ! GCC_SYSTEM_H */
diff --git a/gcc/vec.c b/gcc/vec.c
index beb857fd838..ac3226b5fcb 100644
--- a/gcc/vec.c
+++ b/gcc/vec.c
@@ -201,21 +201,12 @@ qsort_chk_error (const void *p1, const void *p2, const
void *p3,
internal_error ("qsort checking failed");
}
-/* Wrapper around qsort with checking that CMP is consistent on given input.
-
- Strictly speaking, passing invalid (non-transitive, non-anti-commutative)
- comparators to libc qsort can result in undefined behavior. Therefore we
- should ideally perform consistency checks prior to invoking qsort, but in
- order to do that optimally we'd need to sort the array ourselves beforehand
- with a sorting routine known to be "safe". Instead, we expect that most
- implementations in practice will still produce some permutation of input
- array even for invalid comparators, which enables us to perform checks on
- the output array. */
+/* Verify anti-symmetry and transitivity for comparator CMP on sorted array
+ of N SIZE-sized elements pointed to by BASE. */
void
qsort_chk (void *base, size_t n, size_t size,
int (*cmp)(const void *, const void *))
{
- gcc_qsort (base, n, size, cmp);
#if 0
#define LIM(n) (n)
#else
--
2.13.3
