Import compiler-rt 10.0.1 release.

ok kettenis@

1 files changed, 67 insertions, 0 deletions

diff --git a/gnu/llvm/compiler-rt/lib/builtins/enable_execute_stack.c b/gnu/llvm/compiler-rt/lib/builtins/enable_execute_stack.c
new file mode 100644
index 00000000000..e18de4eaebf
--- /dev/null
+++ b/gnu/llvm/compiler-rt/lib/builtins/enable_execute_stack.c
@@ -0,0 +1,67 @@
+//===-- enable_execute_stack.c - Implement __enable_execute_stack ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+#ifndef _WIN32
+#include <sys/mman.h>
+#endif
+
+// #include "config.h"
+// FIXME: CMake - include when cmake system is ready.
+// Remove #define HAVE_SYSCONF 1 line.
+#define HAVE_SYSCONF 1
+
+#ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#else
+#ifndef __APPLE__
+#include <unistd.h>
+#endif // __APPLE__
+#endif // _WIN32
+
+#if __LP64__
+#define TRAMPOLINE_SIZE 48
+#else
+#define TRAMPOLINE_SIZE 40
+#endif
+
+// The compiler generates calls to __enable_execute_stack() when creating
+// trampoline functions on the stack for use with nested functions.
+// It is expected to mark the page(s) containing the address
+// and the next 48 bytes as executable.  Since the stack is normally rw-
+// that means changing the protection on those page(s) to rwx.
+
+COMPILER_RT_ABI void __enable_execute_stack(void *addr) {
+
+#if _WIN32
+  MEMORY_BASIC_INFORMATION mbi;
+  if (!VirtualQuery(addr, &mbi, sizeof(mbi)))
+    return; // We should probably assert here because there is no return value
+  VirtualProtect(mbi.BaseAddress, mbi.RegionSize, PAGE_EXECUTE_READWRITE,
+                 &mbi.Protect);
+#else
+#if __APPLE__
+  // On Darwin, pagesize is always 4096 bytes
+  const uintptr_t pageSize = 4096;
+#elif !defined(HAVE_SYSCONF)
+#error "HAVE_SYSCONF not defined! See enable_execute_stack.c"
+#else
+  const uintptr_t pageSize = sysconf(_SC_PAGESIZE);
+#endif // __APPLE__
+
+  const uintptr_t pageAlignMask = ~(pageSize - 1);
+  uintptr_t p = (uintptr_t)addr;
+  unsigned char *startPage = (unsigned char *)(p & pageAlignMask);
+  unsigned char *endPage =
+      (unsigned char *)((p + TRAMPOLINE_SIZE + pageSize) & pageAlignMask);
+  size_t length = endPage - startPage;
+  (void)mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC);
+#endif
+}