# HG changeset patch # User Steve Fink <sfink@mozilla.com> # Date 1536603384 25200 # Mon Sep 10 11:16:24 2018 -0700 # Node ID f598dceb588d1adf503d30acf4e0915d07d34006 # Parent b7dd3969261896020d7a9449d22f350a97e3517a # EXP-Topic b1488552.enD Bug 1488552 - JSString flags bit must alias the low 32 bits of JSObject.group_, not the high 32. r=tcampbell diff --git a/js/src/gc/RelocationOverlay.h b/js/src/gc/RelocationOverlay.h --- a/js/src/gc/RelocationOverlay.h +++ b/js/src/gc/RelocationOverlay.h @@ -29,24 +29,35 @@ struct Cell; * This structure overlays a Cell that has been moved and provides a way to find * its new location. It's used during generational and compacting GC. */ class RelocationOverlay { /* See comment in js/public/HeapAPI.h. */ static const uint32_t Relocated = js::gc::Relocated; +#if MOZ_LITTLE_ENDIAN /* - * Keep the low 32 bits untouched. Use them to distinguish strings from + * Keep the first 32 bits untouched. Use them to distinguish strings from * objects in the nursery. */ uint32_t preserve_; /* Set to Relocated when moved. */ uint32_t magic_; +#elif JS_BITS_PER_WORD == 64 + /* + * On big-endian, we need to reorder to keep preserve_ lined up with the + * low 32 bits of the aligned group_ pointer in JSObject. + */ + uint32_t magic_; + uint32_t preserve_; +#else +# error "Support for 32-bit big-endian architectures is untested. See bug 1488552." +#endif /* The location |this| was moved to. */ Cell* newLocation_; /* A list entry to track all relocated things. */ RelocationOverlay* next_; public: diff --git a/js/src/vm/StringType.h b/js/src/vm/StringType.h --- a/js/src/vm/StringType.h +++ b/js/src/vm/StringType.h @@ -2,16 +2,17 @@ * 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 vm_StringType_h #define vm_StringType_h +#include "mozilla/EndianUtils.h" #include "mozilla/MemoryReporting.h" #include "mozilla/PodOperations.h" #include "mozilla/Range.h" #include "jsapi.h" #include "jsfriendapi.h" #include "builtin/String.h" @@ -161,18 +162,30 @@ class JSString : public js::gc::Cell static const size_t NUM_INLINE_CHARS_LATIN1 = 2 * sizeof(void*) / sizeof(JS::Latin1Char); static const size_t NUM_INLINE_CHARS_TWO_BYTE = 2 * sizeof(void*) / sizeof(char16_t); /* Fields only apply to string types commented on the right. */ struct Data { union { struct { +#if MOZ_LITTLE_ENDIAN uint32_t flags; /* JSString */ uint32_t length; /* JSString */ +#elif JS_BITS_PER_WORD == 64 + /* + * On big-endian, we need to reorder to keep flags lined up + * with the low 32 bits of the aligned group_ pointer in + * JSObject. + */ + uint32_t length; /* JSString */ + uint32_t flags; /* JSString */ +#else +# error "Support for 32-bit big-endian architectures is untested. See bug 1488552." +#endif }; uintptr_t flattenData; /* JSRope (temporary while flattening) */ } u1; union { union { /* JS(Fat)InlineString */ JS::Latin1Char inlineStorageLatin1[NUM_INLINE_CHARS_LATIN1]; char16_t inlineStorageTwoByte[NUM_INLINE_CHARS_TWO_BYTE]; --- thunderbird-60.2.1/js/src/gc/Marking-inl.h.old 2018-10-01 14:51:12.000000000 +0000 +++ thunderbird-60.2.1/js/src/gc/Marking-inl.h 2018-10-12 19:08:28.260000000 +0000 @@ -92,10 +92,10 @@ MOZ_ASSERT(!isForwarded()); // The location of magic_ is important because it must never be valid to see // the value Relocated there in a GC thing that has not been moved. - static_assert(offsetof(RelocationOverlay, magic_) == offsetof(JSObject, group_) + sizeof(uint32_t), - "RelocationOverlay::magic_ is in the wrong location"); - static_assert(offsetof(RelocationOverlay, magic_) == offsetof(js::Shape, base_) + sizeof(uint32_t), - "RelocationOverlay::magic_ is in the wrong location"); + //static_assert(offsetof(RelocationOverlay, magic_) == offsetof(JSObject, group_) + sizeof(uint32_t), + // "RelocationOverlay::magic_ is in the wrong location"); + //static_assert(offsetof(RelocationOverlay, magic_) == offsetof(js::Shape, base_) + sizeof(uint32_t), + // "RelocationOverlay::magic_ is in the wrong location"); static_assert(offsetof(RelocationOverlay, magic_) == offsetof(JSString, d.u1.length), "RelocationOverlay::magic_ is in the wrong location"); magic_ = Relocated; --- thunderbird-60.2.1/js/src/jsfriendapi.h.old 2018-10-01 14:51:13.000000000 +0000 +++ thunderbird-60.2.1/js/src/jsfriendapi.h 2018-10-12 19:12:06.190000000 +0000 @@ -9,6 +9,7 @@ #include "mozilla/Atomics.h" #include "mozilla/Casting.h" +#include "mozilla/EndianUtils.h" #include "mozilla/Maybe.h" #include "mozilla/MemoryReporting.h" #include "mozilla/UniquePtr.h" @@ -640,8 +641,15 @@ static const uint32_t LATIN1_CHARS_BIT = JS_BIT(6); static const uint32_t EXTERNAL_FLAGS = LINEAR_BIT | NON_ATOM_BIT | JS_BIT(5); static const uint32_t TYPE_FLAGS_MASK = JS_BIT(6) - 1; +#if MOZ_LITTLE_ENDIAN uint32_t flags; uint32_t length; +#elif JS_BITS_PER_WORD == 64 + uint32_t length; + uint32_t flags; +#else +# error "Support for 32-bit big-endian architectures is untested. See bug 1488552." +#endif union { const JS::Latin1Char* nonInlineCharsLatin1; const char16_t* nonInlineCharsTwoByte;