+
+/* -----------------------------------------------------------------------------
+ Allocating executable memory
+ -------------------------------------------------------------------------- */
+
+/* Heavily arch-specific, I'm afraid.. */
+
+/*
+ * Allocate len bytes which are readable, writable, and executable.
+ *
+ * ToDo: If this turns out to be a performance bottleneck, one could
+ * e.g. cache the last VirtualProtect/mprotect-ed region and do
+ * nothing in case of a cache hit.
+ */
+void*
+stgMallocBytesRWX(int len)
+{
+ void *addr = stgMallocBytes(len, "mallocBytesRWX");
+#if defined(i386_HOST_ARCH) && defined(_WIN32)
+ /* This could be necessary for processors which distinguish between READ and
+ EXECUTE memory accesses, e.g. Itaniums. */
+ DWORD dwOldProtect = 0;
+ if (VirtualProtect (addr, len, PAGE_EXECUTE_READWRITE, &dwOldProtect) == 0) {
+ barf("mallocBytesRWX: failed to protect 0x%p; error=%lu; old protection: %lu\n",
+ addr, (unsigned long)GetLastError(), (unsigned long)dwOldProtect);
+ }
+#elif defined(openbsd_HOST_OS) || defined(linux_HOST_OS) || defined(darwin_HOST_OS)
+ /* malloced memory isn't executable by default on OpenBSD */
+ my_uintptr_t pageSize = sysconf(_SC_PAGESIZE);
+ my_uintptr_t mask = ~(pageSize - 1);
+ my_uintptr_t startOfFirstPage = ((my_uintptr_t)addr ) & mask;
+ my_uintptr_t startOfLastPage = ((my_uintptr_t)addr + len - 1) & mask;
+ my_uintptr_t size = startOfLastPage - startOfFirstPage + pageSize;
+ if (mprotect((void*)startOfFirstPage, (size_t)size, PROT_EXEC | PROT_READ | PROT_WRITE) != 0) {
+ barf("mallocBytesRWX: failed to protect 0x%p\n", addr);
+ }