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// RUN: %libomptarget-compilexx-run-and-check-generic
// Assuming the stack is allocated on the host starting at high addresses, the
// host memory layout for the following program looks like this:
//
// low addr <----------------------------------------------------- high addr
// | 16 bytes | 16 bytes | 16 bytes | ? bytes |
// | collidePost | s | collidePre | stackPad |
// | | x | y | z | | |
// `-------------'
// ^ `--------'
// | ^
// | |
// | `-- too much padding (< 16 bytes) for s maps here
// |
// `------------------array extension error maps here
//
// libomptarget used to add too much padding to the device allocation of s and
// map it back to the host at the location indicated above when all of the
// following conditions were true:
// - Multiple members (s.y and s.z below) were mapped. In this case, initial
// padding might be needed to ensure later mapped members (s.z) are aligned
// properly on the device. (If the first member in the struct, s.x, were also
// mapped, then the correct initial padding would always be zero.)
// - mod16 = &s % 16 was not a power of 2 (e.g., 0x7ffcce2b584e % 16 = 14).
// libomptarget then incorrectly assumed mod16 was the existing host memory
// alignment of s. (The fix was to only look for alignments that are powers
// of 2.)
// - &s.y % mod16 was > 1 (e.g., 0x7ffcce2b584f % 14 = 11). libomptarget added
// padding of that size for s, but at most 1 byte is ever actually needed.
//
// Below, we try many sizes of stackPad to try to produce those conditions.
//
// When collidePost was then mapped to the same host memory as the unnecessary
// padding for s, libomptarget reported an array extension error. collidePost
// is never fully contained within that padding (which would avoid the extension
// error) because collidePost is 16 bytes while the padding is always less than
// 16 bytes due to the modulo operations.
#include <stdint.h>
#include <stdio.h>
template <typename StackPad>
void test() {
StackPad stackPad;
struct S { char x; char y[7]; char z[8]; };
struct S collidePre, s, collidePost;
uintptr_t mod16 = (uintptr_t)&s % 16;
fprintf(stderr, "&s = %p\n", &s);
fprintf(stderr, "&s %% 16 = %lu\n", mod16);
if (mod16) {
fprintf(stderr, "&s.y = %p\n", &s.y);
fprintf(stderr, "&s.y %% %lu = %lu\n", mod16, (uintptr_t)&s.y % mod16);
}
fprintf(stderr, "&collidePre = %p\n", &collidePre);
fprintf(stderr, "&collidePost = %p\n", &collidePost);
#pragma omp target data map(to:s.y, s.z)
#pragma omp target data map(to:collidePre, collidePost)
;
}
#define TEST(StackPad) \
fprintf(stderr, "-------------------------------------\n"); \
fprintf(stderr, "StackPad=%s\n", #StackPad); \
test<StackPad>()
int main() {
TEST(char[1]);
TEST(char[2]);
TEST(char[3]);
TEST(char[4]);
TEST(char[5]);
TEST(char[6]);
TEST(char[7]);
TEST(char[8]);
TEST(char[9]);
TEST(char[10]);
TEST(char[11]);
TEST(char[12]);
TEST(char[13]);
TEST(char[14]);
TEST(char[15]);
TEST(char[16]);
// CHECK: pass
printf("pass\n");
return 0;
}
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