/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef js_Utility_h #define js_Utility_h #include "mozilla/Assertions.h" #include "mozilla/Attributes.h" #include "mozilla/Compiler.h" #include "mozilla/Move.h" #include "mozilla/Scoped.h" #include "mozilla/TemplateLib.h" #include #include #ifdef JS_OOM_DO_BACKTRACES #include #include #endif #include "jstypes.h" /* The public JS engine namespace. */ namespace JS {} /* The mozilla-shared reusable template/utility namespace. */ namespace mozilla {} /* The private JS engine namespace. */ namespace js {} /* * Pattern used to overwrite freed memory. If you are accessing an object with * this pattern, you probably have a dangling pointer. */ #define JS_FREE_PATTERN 0xDA #define JS_ASSERT(expr) MOZ_ASSERT(expr) #define JS_ASSERT_IF(cond, expr) MOZ_ASSERT_IF(cond, expr) #define JS_ALWAYS_TRUE(expr) MOZ_ALWAYS_TRUE(expr) #define JS_ALWAYS_FALSE(expr) MOZ_ALWAYS_FALSE(expr) #ifdef DEBUG # ifdef JS_THREADSAFE # define JS_THREADSAFE_ASSERT(expr) JS_ASSERT(expr) # else # define JS_THREADSAFE_ASSERT(expr) ((void) 0) # endif #else # define JS_THREADSAFE_ASSERT(expr) ((void) 0) #endif #if defined(DEBUG) # define JS_DIAGNOSTICS_ASSERT(expr) MOZ_ASSERT(expr) #elif defined(JS_CRASH_DIAGNOSTICS) # define JS_DIAGNOSTICS_ASSERT(expr) do { if (!(expr)) MOZ_CRASH(); } while(0) #else # define JS_DIAGNOSTICS_ASSERT(expr) ((void) 0) #endif #define JS_STATIC_ASSERT(cond) static_assert(cond, "JS_STATIC_ASSERT") #define JS_STATIC_ASSERT_IF(cond, expr) MOZ_STATIC_ASSERT_IF(cond, expr, "JS_STATIC_ASSERT_IF") extern MOZ_NORETURN JS_PUBLIC_API(void) JS_Assert(const char *s, const char *file, int ln); /* * Abort the process in a non-graceful manner. This will cause a core file, * call to the debugger or other moral equivalent as well as causing the * entire process to stop. */ extern JS_PUBLIC_API(void) JS_Abort(void); /* * Custom allocator support for SpiderMonkey */ #if defined JS_USE_CUSTOM_ALLOCATOR # include "jscustomallocator.h" #else # ifdef DEBUG /* * In order to test OOM conditions, when the testing function * oomAfterAllocations COUNT is passed, we fail continuously after the NUM'th * allocation from now. */ extern JS_PUBLIC_DATA(uint32_t) OOM_maxAllocations; /* set in builtins/TestingFunctions.cpp */ extern JS_PUBLIC_DATA(uint32_t) OOM_counter; /* data race, who cares. */ #ifdef JS_OOM_DO_BACKTRACES #define JS_OOM_BACKTRACE_SIZE 32 static JS_ALWAYS_INLINE void PrintBacktrace() { void* OOM_trace[JS_OOM_BACKTRACE_SIZE]; char** OOM_traceSymbols = NULL; int32_t OOM_traceSize = 0; int32_t OOM_traceIdx = 0; OOM_traceSize = backtrace(OOM_trace, JS_OOM_BACKTRACE_SIZE); OOM_traceSymbols = backtrace_symbols(OOM_trace, OOM_traceSize); if (!OOM_traceSymbols) return; for (OOM_traceIdx = 0; OOM_traceIdx < OOM_traceSize; ++OOM_traceIdx) { fprintf(stderr, "#%d %s\n", OOM_traceIdx, OOM_traceSymbols[OOM_traceIdx]); } free(OOM_traceSymbols); } #define JS_OOM_EMIT_BACKTRACE() \ do {\ fprintf(stderr, "Forcing artificial memory allocation function failure:\n");\ PrintBacktrace();\ } while (0) # else # define JS_OOM_EMIT_BACKTRACE() do {} while(0) #endif /* JS_OOM_DO_BACKTRACES */ # define JS_OOM_POSSIBLY_FAIL() \ do \ { \ if (++OOM_counter > OOM_maxAllocations) { \ JS_OOM_EMIT_BACKTRACE();\ return NULL; \ } \ } while (0) # define JS_OOM_POSSIBLY_FAIL_REPORT(cx) \ do \ { \ if (++OOM_counter > OOM_maxAllocations) { \ JS_OOM_EMIT_BACKTRACE();\ js_ReportOutOfMemory(cx);\ return NULL; \ } \ } while (0) # else # define JS_OOM_POSSIBLY_FAIL() do {} while(0) # define JS_OOM_POSSIBLY_FAIL_REPORT(cx) do {} while(0) # endif /* DEBUG */ static JS_INLINE void* js_malloc(size_t bytes) { JS_OOM_POSSIBLY_FAIL(); return malloc(bytes); } static JS_INLINE void* js_calloc(size_t bytes) { JS_OOM_POSSIBLY_FAIL(); return calloc(bytes, 1); } static JS_INLINE void* js_realloc(void* p, size_t bytes) { JS_OOM_POSSIBLY_FAIL(); return realloc(p, bytes); } static JS_INLINE void js_free(void* p) { free(p); } #endif/* JS_USE_CUSTOM_ALLOCATOR */ /* * JS_ROTATE_LEFT32 * * There is no rotate operation in the C Language so the construct (a << 4) | * (a >> 28) is used instead. Most compilers convert this to a rotate * instruction but some versions of MSVC don't without a little help. To get * MSVC to generate a rotate instruction, we have to use the _rotl intrinsic * and use a pragma to make _rotl inline. * * MSVC in VS2005 will do an inline rotate instruction on the above construct. */ #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \ defined(_M_X64)) #include #pragma intrinsic(_rotl) #define JS_ROTATE_LEFT32(a, bits) _rotl(a, bits) #else #define JS_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits)))) #endif #include /* * Low-level memory management in SpiderMonkey: * * ** Do not use the standard malloc/free/realloc: SpiderMonkey allows these * to be redefined (via JS_USE_CUSTOM_ALLOCATOR) and Gecko even #define's * these symbols. * * ** Do not use the builtin C++ operator new and delete: these throw on * error and we cannot override them not to. * * Allocation: * * - If the lifetime of the allocation is tied to the lifetime of a GC-thing * (that is, finalizing the GC-thing will free the allocation), call one of * the following functions: * * JSContext::{malloc_,realloc_,calloc_,new_} * JSRuntime::{malloc_,realloc_,calloc_,new_} * * These functions accumulate the number of bytes allocated which is used as * part of the GC-triggering heuristic. * * The difference between the JSContext and JSRuntime versions is that the * cx version reports an out-of-memory error on OOM. (This follows from the * general SpiderMonkey idiom that a JSContext-taking function reports its * own errors.) * * - Otherwise, use js_malloc/js_realloc/js_calloc/js_free/js_new * * Deallocation: * * - Ordinarily, use js_free/js_delete. * * - For deallocations during GC finalization, use one of the following * operations on the FreeOp provided to the finalizer: * * FreeOp::{free_,delete_} * * The advantage of these operations is that the memory is batched and freed * on another thread. */ #define JS_NEW_BODY(allocator, t, parms) \ void *memory = allocator(sizeof(t)); \ return memory ? new(memory) t parms : NULL; /* * Given a class which should provide 'new' methods, add * JS_DECLARE_NEW_METHODS (see JSContext for a usage example). This * adds news with up to 12 parameters. Add more versions of new below if * you need more than 12 parameters. * * Note: Do not add a ; at the end of a use of JS_DECLARE_NEW_METHODS, * or the build will break. */ #define JS_DECLARE_NEW_METHODS(NEWNAME, ALLOCATOR, QUALIFIERS)\ template \ QUALIFIERS T *NEWNAME() {\ JS_NEW_BODY(ALLOCATOR, T, ())\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1) {\ JS_NEW_BODY(ALLOCATOR, T, (p1))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7, P8 p8) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7, p8))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7, P8 p8, P9 p9) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7, p8, p9))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7, P8 p8, P9 p9, P10 p10) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7, p8, p9, p10))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7, P8 p8, P9 p9, P10 p10, P11 p11) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11))\ }\ \ template \ QUALIFIERS T *NEWNAME(P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6, P7 p7, P8 p8, P9 p9, P10 p10, P11 p11, P12 p12) {\ JS_NEW_BODY(ALLOCATOR, T, (p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12))\ }\ JS_DECLARE_NEW_METHODS(js_new, js_malloc, static JS_ALWAYS_INLINE) template static JS_ALWAYS_INLINE void js_delete(T *p) { if (p) { p->~T(); js_free(p); } } template static JS_ALWAYS_INLINE void js_delete_poison(T *p) { if (p) { p->~T(); memset(p, 0x3B, sizeof(T)); js_free(p); } } template static JS_ALWAYS_INLINE T * js_pod_malloc() { return (T *)js_malloc(sizeof(T)); } template static JS_ALWAYS_INLINE T * js_pod_calloc() { return (T *)js_calloc(sizeof(T)); } template static JS_ALWAYS_INLINE T * js_pod_malloc(size_t numElems) { if (numElems & mozilla::tl::MulOverflowMask::value) return NULL; return (T *)js_malloc(numElems * sizeof(T)); } template static JS_ALWAYS_INLINE T * js_pod_calloc(size_t numElems) { if (numElems & mozilla::tl::MulOverflowMask::value) return NULL; return (T *)js_calloc(numElems * sizeof(T)); } namespace js { template struct ScopedFreePtrTraits { typedef T* type; static T* empty() { return NULL; } static void release(T* ptr) { js_free(ptr); } }; SCOPED_TEMPLATE(ScopedJSFreePtr, ScopedFreePtrTraits) template struct ScopedDeletePtrTraits : public ScopedFreePtrTraits { static void release(T *ptr) { js_delete(ptr); } }; SCOPED_TEMPLATE(ScopedJSDeletePtr, ScopedDeletePtrTraits) template struct ScopedReleasePtrTraits : public ScopedFreePtrTraits { static void release(T *ptr) { if (ptr) ptr->release(); } }; SCOPED_TEMPLATE(ScopedReleasePtr, ScopedReleasePtrTraits) } /* namespace js */ namespace js { /* Integral types for all hash functions. */ typedef uint32_t HashNumber; const unsigned HashNumberSizeBits = 32; namespace detail { /* * Given a raw hash code, h, return a number that can be used to select a hash * bucket. * * This function aims to produce as uniform an output distribution as possible, * especially in the most significant (leftmost) bits, even though the input * distribution may be highly nonrandom, given the constraints that this must * be deterministic and quick to compute. * * Since the leftmost bits of the result are best, the hash bucket index is * computed by doing ScrambleHashCode(h) / (2^32/N) or the equivalent * right-shift, not ScrambleHashCode(h) % N or the equivalent bit-mask. * * FIXME: OrderedHashTable uses a bit-mask; see bug 775896. */ inline HashNumber ScrambleHashCode(HashNumber h) { /* * Simply returning h would not cause any hash tables to produce wrong * answers. But it can produce pathologically bad performance: The caller * right-shifts the result, keeping only the highest bits. The high bits of * hash codes are very often completely entropy-free. (So are the lowest * bits.) * * So we use Fibonacci hashing, as described in Knuth, The Art of Computer * Programming, 6.4. This mixes all the bits of the input hash code h. * * The value of goldenRatio is taken from the hex * expansion of the golden ratio, which starts 1.9E3779B9.... * This value is especially good if values with consecutive hash codes * are stored in a hash table; see Knuth for details. */ static const HashNumber goldenRatio = 0x9E3779B9U; return h * goldenRatio; } } /* namespace detail */ } /* namespace js */ namespace JS { /* * Methods for poisoning GC heap pointer words and checking for poisoned words. * These are in this file for use in Value methods and so forth. * * If the moving GC hazard analysis is in use and detects a non-rooted stack * pointer to a GC thing, one byte of that pointer is poisoned to refer to an * invalid location. For both 32 bit and 64 bit systems, the fourth byte of the * pointer is overwritten, to reduce the likelihood of accidentally changing * a live integer value. */ inline void PoisonPtr(void *v) { #if defined(JSGC_ROOT_ANALYSIS) && defined(DEBUG) uint8_t *ptr = (uint8_t *) v + 3; *ptr = JS_FREE_PATTERN; #endif } template inline bool IsPoisonedPtr(T *v) { #if defined(JSGC_ROOT_ANALYSIS) && defined(DEBUG) uint32_t mask = uintptr_t(v) & 0xff000000; return mask == uint32_t(JS_FREE_PATTERN << 24); #else return false; #endif } } /* sixgill annotation defines */ #ifndef HAVE_STATIC_ANNOTATIONS # define HAVE_STATIC_ANNOTATIONS # ifdef XGILL_PLUGIN # define STATIC_PRECONDITION(COND) __attribute__((precondition(#COND))) # define STATIC_PRECONDITION_ASSUME(COND) __attribute__((precondition_assume(#COND))) # define STATIC_POSTCONDITION(COND) __attribute__((postcondition(#COND))) # define STATIC_POSTCONDITION_ASSUME(COND) __attribute__((postcondition_assume(#COND))) # define STATIC_INVARIANT(COND) __attribute__((invariant(#COND))) # define STATIC_INVARIANT_ASSUME(COND) __attribute__((invariant_assume(#COND))) # define STATIC_PASTE2(X,Y) X ## Y # define STATIC_PASTE1(X,Y) STATIC_PASTE2(X,Y) # define STATIC_ASSERT(COND) \ JS_BEGIN_MACRO \ __attribute__((assert_static(#COND), unused)) \ int STATIC_PASTE1(assert_static_, __COUNTER__); \ JS_END_MACRO # define STATIC_ASSUME(COND) \ JS_BEGIN_MACRO \ __attribute__((assume_static(#COND), unused)) \ int STATIC_PASTE1(assume_static_, __COUNTER__); \ JS_END_MACRO # define STATIC_ASSERT_RUNTIME(COND) \ JS_BEGIN_MACRO \ __attribute__((assert_static_runtime(#COND), unused)) \ int STATIC_PASTE1(assert_static_runtime_, __COUNTER__); \ JS_END_MACRO # else /* XGILL_PLUGIN */ # define STATIC_PRECONDITION(COND) /* nothing */ # define STATIC_PRECONDITION_ASSUME(COND) /* nothing */ # define STATIC_POSTCONDITION(COND) /* nothing */ # define STATIC_POSTCONDITION_ASSUME(COND) /* nothing */ # define STATIC_INVARIANT(COND) /* nothing */ # define STATIC_INVARIANT_ASSUME(COND) /* nothing */ # define STATIC_ASSERT(COND) JS_BEGIN_MACRO /* nothing */ JS_END_MACRO # define STATIC_ASSUME(COND) JS_BEGIN_MACRO /* nothing */ JS_END_MACRO # define STATIC_ASSERT_RUNTIME(COND) JS_BEGIN_MACRO /* nothing */ JS_END_MACRO # endif /* XGILL_PLUGIN */ # define STATIC_SKIP_INFERENCE STATIC_INVARIANT(skip_inference()) #endif /* HAVE_STATIC_ANNOTATIONS */ #endif /* js_Utility_h */