1 files changed, 175 insertions, 0 deletions
diff --git a/lib/scudo/standalone/common.h b/lib/scudo/standalone/common.h
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+++ b/lib/scudo/standalone/common.h
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+//===-- common.h ------------------------------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_COMMON_H_
+#define SCUDO_COMMON_H_
+
+#include "internal_defs.h"
+
+#include "fuchsia.h"
+#include "linux.h"
+
+#include <stddef.h>
+#include <string.h>
+
+namespace scudo {
+
+template <class Dest, class Source> INLINE Dest bit_cast(const Source &S) {
+  COMPILER_CHECK(sizeof(Dest) == sizeof(Source));
+  Dest D;
+  memcpy(&D, &S, sizeof(D));
+  return D;
+}
+
+INLINE constexpr uptr roundUpTo(uptr X, uptr Boundary) {
+  return (X + Boundary - 1) & ~(Boundary - 1);
+}
+
+INLINE constexpr uptr roundDownTo(uptr X, uptr Boundary) {
+  return X & ~(Boundary - 1);
+}
+
+INLINE constexpr bool isAligned(uptr X, uptr Alignment) {
+  return (X & (Alignment - 1)) == 0;
+}
+
+template <class T> constexpr T Min(T A, T B) { return A < B ? A : B; }
+
+template <class T> constexpr T Max(T A, T B) { return A > B ? A : B; }
+
+template <class T> void Swap(T &A, T &B) {
+  T Tmp = A;
+  A = B;
+  B = Tmp;
+}
+
+INLINE bool isPowerOfTwo(uptr X) { return (X & (X - 1)) == 0; }
+
+INLINE uptr getMostSignificantSetBitIndex(uptr X) {
+  DCHECK_NE(X, 0U);
+  return SCUDO_WORDSIZE - 1U - static_cast<uptr>(__builtin_clzl(X));
+}
+
+INLINE uptr roundUpToPowerOfTwo(uptr Size) {
+  DCHECK(Size);
+  if (isPowerOfTwo(Size))
+    return Size;
+  const uptr Up = getMostSignificantSetBitIndex(Size);
+  DCHECK_LT(Size, (1UL << (Up + 1)));
+  DCHECK_GT(Size, (1UL << Up));
+  return 1UL << (Up + 1);
+}
+
+INLINE uptr getLeastSignificantSetBitIndex(uptr X) {
+  DCHECK_NE(X, 0U);
+  return static_cast<uptr>(__builtin_ctzl(X));
+}
+
+INLINE uptr getLog2(uptr X) {
+  DCHECK(isPowerOfTwo(X));
+  return getLeastSignificantSetBitIndex(X);
+}
+
+INLINE u32 getRandomU32(u32 *State) {
+  // ANSI C linear congruential PRNG (16-bit output).
+  // return (*State = *State * 1103515245 + 12345) >> 16;
+  // XorShift (32-bit output).
+  *State ^= *State << 13;
+  *State ^= *State >> 17;
+  *State ^= *State << 5;
+  return *State;
+}
+
+INLINE u32 getRandomModN(u32 *State, u32 N) {
+  return getRandomU32(State) % N; // [0, N)
+}
+
+template <typename T> INLINE void shuffle(T *A, u32 N, u32 *RandState) {
+  if (N <= 1)
+    return;
+  u32 State = *RandState;
+  for (u32 I = N - 1; I > 0; I--)
+    Swap(A[I], A[getRandomModN(&State, I + 1)]);
+  *RandState = State;
+}
+
+// Hardware specific inlinable functions.
+
+INLINE void yieldProcessor(u8 Count) {
+#if defined(__i386__) || defined(__x86_64__)
+  __asm__ __volatile__("" ::: "memory");
+  for (u8 I = 0; I < Count; I++)
+    __asm__ __volatile__("pause");
+#elif defined(__aarch64__) || defined(__arm__)
+  __asm__ __volatile__("" ::: "memory");
+  for (u8 I = 0; I < Count; I++)
+    __asm__ __volatile__("yield");
+#endif
+  __asm__ __volatile__("" ::: "memory");
+}
+
+// Platform specific functions.
+
+void yieldPlatform();
+
+extern uptr PageSizeCached;
+uptr getPageSizeSlow();
+INLINE uptr getPageSizeCached() {
+  if (LIKELY(PageSizeCached))
+    return PageSizeCached;
+  return getPageSizeSlow();
+}
+
+u32 getNumberOfCPUs();
+
+const char *getEnv(const char *Name);
+
+u64 getMonotonicTime();
+
+// Our randomness gathering function is limited to 256 bytes to ensure we get
+// as many bytes as requested, and avoid interruptions (on Linux).
+constexpr uptr MaxRandomLength = 256U;
+bool getRandom(void *Buffer, uptr Length, bool Blocking = false);
+
+// Platform memory mapping functions.
+
+#define MAP_ALLOWNOMEM (1U << 0)
+#define MAP_NOACCESS (1U << 1)
+#define MAP_RESIZABLE (1U << 2)
+
+// Our platform memory mapping use is restricted to 3 scenarios:
+// - reserve memory at a random address (MAP_NOACCESS);
+// - commit memory in a previously reserved space;
+// - commit memory at a random address.
+// As such, only a subset of parameters combinations is valid, which is checked
+// by the function implementation. The Data parameter allows to pass opaque
+// platform specific data to the function.
+// Returns nullptr on error or dies if MAP_ALLOWNOMEM is not specified.
+void *map(void *Addr, uptr Size, const char *Name, uptr Flags = 0,
+          MapPlatformData *Data = nullptr);
+
+// Indicates that we are getting rid of the whole mapping, which might have
+// further consequences on Data, depending on the platform.
+#define UNMAP_ALL (1U << 0)
+
+void unmap(void *Addr, uptr Size, uptr Flags = 0,
+           MapPlatformData *Data = nullptr);
+
+void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size,
+                      MapPlatformData *Data = nullptr);
+
+// Internal map & unmap fatal error. This must not call map().
+void NORETURN dieOnMapUnmapError(bool OutOfMemory = false);
+
+// Logging related functions.
+
+void setAbortMessage(const char *Message);
+
+} // namespace scudo
+
+#endif // SCUDO_COMMON_H_