// This program is a thorough test of the LOADVn/STOREVn shadow memory
// operations.
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "memcheck/memcheck.h"
// All the sizes here are in *bytes*, not bits.
typedef unsigned char U1;
typedef unsigned short U2;
typedef unsigned int U4;
typedef unsigned long long U8;
typedef float F4;
typedef double F8;
#define SZB_OF_a 64
// a[] is the array in which we do our loads and stores.
// b[] is another one in which we do some copying.
U8 a [SZB_OF_a / 8]; // Type is U8 to ensure it's 8-aligned
U8 b [SZB_OF_a / 8]; // same size as a[]
// XXX: should check the error cases for SET/GET_VBITS also
// For the byte 'x', build a value of 'size' bytes from that byte, eg:
// size 1 --> x
// size 2 --> xx
// size 4 --> xxxx
// size 8 --> xxxxxxxx
// where the 0 bits are seen by Memcheck as defined, and the 1 bits are
// seen as undefined (ie. the value of each bit matches its V bit, ie. the
// resulting value is the same as its metavalue).
//
U8 build(int size, U1 byte)
{
int i;
U8 mask = 0;
U8 shres;
U8 res = 0xffffffffffffffffULL, res2;
(void)VALGRIND_MAKE_MEM_UNDEFINED(&res, 8);
assert(1 == size || 2 == size || 4 == size || 8 == size);
for (i = 0; i < size; i++) {
mask <<= 8;
mask |= (U8)byte;
}
res &= mask;
// res is now considered partially defined, but we know exactly what its
// value is (it happens to be the same as its metavalue).
(void)VALGRIND_GET_VBITS(&res, &shres, 8);
res2 = res;
(void)VALGRIND_MAKE_MEM_DEFINED(&res2, 8); // avoid the 'undefined' warning
assert(res2 == shres);
return res;
}
// Check that all the bytes in a[x..y-1] have their V byte equal
// to either 'expected_byte' or 'expected_byte_alt'.
// 'str' and 'offset' are only used for printing an error message if
// something goes wrong.
void check_all(U4 x, U4 y, U1 expected_byte, U1 expected_byte_alt,
char* str, int offset)
{
U1 sh[SZB_OF_a]; // Used for getting a[]'s V bits
int i;
(void)VALGRIND_GET_VBITS(a, sh, sizeof(a));
for (i = x; i < y; i++) {
if ( expected_byte != sh[i] && expected_byte_alt != sh[i] ) {
fprintf(stderr, "\n\nFAILURE: %s, offset %d, byte %d -- "
"is 0x%x, should be 0x%x or 0x%x\n\n",
str, offset, i, sh[i], expected_byte,
expected_byte_alt);
exit(1);
}
}
}
int main(void)
{
int h, i, j;
U1 *undefA, expected_byte, expected_byte_alt;
if (0 == RUNNING_ON_VALGRIND) {
fprintf(stderr,
"error: this program only works when run under Valgrind\n");
exit(1);
}
// Check a[] has the expected alignment, and that it's not too high in
// the address space (which would trigger the slow cases in
// LOADVn/STOREVn) on 64-bit platforms).
assert( 0 == (long)a % 8);
if (sizeof(void*) == 8) {
assert( ((U1*)(&a[0])) < ((U1*)(32ULL * 1024*1024*1024)/*32G*/) );
}
// Check basic types have the expected sizes.
assert(1 == sizeof(U1));
assert(2 == sizeof(U2));
assert(4 == sizeof(U4));
assert(8 == sizeof(U8));
// Create an array of values that has all the possible V bit metavalues.
// Because 0 represents a defined bit, and because undefA[] is initially
// zeroed, we have the nice property that:
//
// i == undefA[i] == V_bits_of(undefA[i])
//
// which is useful for testing below.
undefA = calloc(1, 256); // one for each possible undefinedness value
(void)VALGRIND_MAKE_MEM_UNDEFINED(undefA, 256);
for (i = 0; i < 256; i++) {
undefA[i] &= i;
}
// This code does a whole lot of reads and writes of a particular size
// (NNN = 1, 2, 4 or 8), with varying alignments, of values with
// different not/partially/fully defined metavalues, and checks that the
// V bits are set in a[] as expected using GET_VBITS.
//
// 'Ty' is the type of the thing we are copying. It can be an integer
// type or an FP type. 'ITy' is the same-sized integer type (and thus
// will be the same as 'Ty' if 'ITy' is an integer type). 'ITy' is used
// when doing shifting/masking and stuff like that.
#define DO(NNN, Ty, ITy, isF4) \
fprintf(stderr, "-- NNN: %d %s %s ------------------------\n", \
NNN, #Ty, #ITy); \
/* For all of the alignments from (0..NNN-1), eg. if NNN==4, we do */ \
/* alignments of 0, 1, 2, 3. */ \
for (h = 0; h < NNN; h++) { \
\
size_t n = sizeof(a); \
size_t nN = n / sizeof(Ty); \
Ty* aN = (Ty*)a; \
Ty* bN = (Ty*)b; \
Ty* aNb = (Ty*)(((U1*)aN) + h); /* set offset from a[] */ \
Ty* bNb = (Ty*)(((U1*)bN) + h); /* set offset from b[] */ \
\
fprintf(stderr, "h = %d (checking %d..%d) ", h, h, (int)(n-NNN+h)); \
\
/* For each of the 256 possible V byte values... */ \
for (j = 0; j < 256; j++) { \
/* build the value for i (one of: i, ii, iiii, iiiiiiii) */ \
U8 tmp = build(NNN, j); \
ITy undefN_ITy = (ITy)tmp; \
Ty* undefN_Ty; \
{ /* This just checks that no overflow occurred when squeezing */ \
/* the output of build() into a variable of type 'Ty'. */ \
U8 tmpDef = tmp; \
ITy undefN_ITyDef = undefN_ITy; \
(void)VALGRIND_MAKE_MEM_DEFINED(&tmpDef, 8 ); \
(void)VALGRIND_MAKE_MEM_DEFINED(&undefN_ITyDef, NNN); \
assert(tmpDef == (U8)undefN_ITyDef); \
} \
\
/* We have to use an array for undefN_Ty -- because if we try to
* convert an integer type from build into an FP type with a
* straight cast -- eg "float f = (float)i" -- the value gets
* converted. With this pointer/array nonsense the exact bit
* pattern gets used as an FP value unchanged (that FP value is
* undoubtedly nonsense, but that's not a problem here). */ \
undefN_Ty = (Ty*)&undefN_ITy; \
if (0 == j % 32) fprintf(stderr, "%d...", j); /* progress meter */ \
\
/* A nasty exception: most machines so far (x86/PPC32/PPC64)
* don't have 32-bit floats. So 32-bit floats get cast to 64-bit
* floats. Memcheck does a PCast in this case, which means that if
* any V bits for the 32-bit float are undefined (ie. 0 != j), all
* the V bits in the 64-bit float are undefined. So account for
* this when checking. AMD64 typically does FP arithmetic on
* SSE, effectively giving it access to 32-bit FP registers. So
* in short, for floats, we have to allow either 'j' or 0xFF
* as an acceptable result. Sigh. */ \
if (isF4) { \
expected_byte = j; \
expected_byte_alt = 0 != j ? 0xFF : j; \
} else { \
expected_byte = j; \
expected_byte_alt = j; \
} \
\
/* STOREVn. Note that we use the first element of the undefN_Ty
* array, as explained above. */ \
for (i = 0; i < nN-1; i++) { aNb[i] = undefN_Ty[0]; } \
check_all(h, n-NNN+h, expected_byte, expected_byte_alt, \
"STOREVn", h); \
\
/* LOADVn -- by copying the values to one place and then back,
* we ensure that LOADVn gets exercised. */ \
for (i = 0; i < nN-1; i++) { bNb[i] = aNb[i]; } \
for (i = 0; i < nN-1; i++) { aNb[i] = bNb[i]; } \
check_all(h, n-NNN+h, expected_byte, expected_byte_alt, "LOADVn", h); \
} \
fprintf(stderr, "\n"); \
}
// For sizes 4 and 8 we do both integer and floating-point types. The
// reason being that on 32-bit machines just using integer types never
// exercises LOADV8/STOREV8 -- for integer types these loads/stores get
// broken into two 32-bit loads/stores.
DO(1, U1, U1, /*isF4*/0);
DO(2, U2, U2, /*isF4*/0);
DO(4, U4, U4, /*isF4*/0);
DO(4, F4, U4, /*isF4*/1);
DO(8, U8, U8, /*isF4*/0);
DO(8, F8, U8, /*isF4*/0);
return 0;
}