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Diffstat (limited to 'memory/replace/dmd/DMD.h')
| -rw-r--r-- | memory/replace/dmd/DMD.h | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/memory/replace/dmd/DMD.h b/memory/replace/dmd/DMD.h new file mode 100644 index 0000000000..c057047800 --- /dev/null +++ b/memory/replace/dmd/DMD.h @@ -0,0 +1,291 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=2 et sw=2 tw=80: */ +/* 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 DMD_h___ +#define DMD_h___ + +#include <stdarg.h> +#include <string.h> + +#include <utility> + +#include "mozilla/DebugOnly.h" +#include "mozilla/Types.h" +#include "mozilla/UniquePtr.h" +#include "replace_malloc_bridge.h" + +namespace mozilla { + +class JSONWriteFunc; + +namespace dmd { + +struct Sizes { + size_t mStackTracesUsed; + size_t mStackTracesUnused; + size_t mStackTraceTable; + size_t mLiveBlockTable; + size_t mDeadBlockTable; + + Sizes() { Clear(); } + void Clear() { memset(this, 0, sizeof(Sizes)); } +}; + +// See further below for a description of each method. The DMDFuncs class +// should contain a virtual method for each of them (except IsRunning, +// which can be inferred from the DMDFuncs singleton existing). +struct DMDFuncs { + virtual void Report(const void*); + + virtual void ReportOnAlloc(const void*); + + virtual void ClearReports(); + + virtual void Analyze(UniquePtr<JSONWriteFunc>); + + virtual void SizeOf(Sizes*); + + virtual void StatusMsg(const char*, va_list) MOZ_FORMAT_PRINTF(2, 0); + + virtual void ResetEverything(const char*); + +#ifndef REPLACE_MALLOC_IMPL + // We deliberately don't use ReplaceMalloc::GetDMDFuncs here, because if we + // did, the following would happen. + // - The code footprint of each call to Get() larger as GetDMDFuncs ends + // up inlined. + // - When no replace-malloc library is loaded, the number of instructions + // executed is equivalent, but don't necessarily fit in the same cache + // line. + // - When a non-DMD replace-malloc library is loaded, the overhead is + // higher because there is first a check for the replace malloc bridge + // and then for the DMDFuncs singleton. + // Initializing the DMDFuncs singleton on the first access makes the + // overhead even worse. Either Get() is inlined and massive, or it isn't + // and a simple value check becomes a function call. + static DMDFuncs* Get() { return sSingleton.Get(); } + + private: + // Wrapper class keeping a pointer to the DMD functions. It is statically + // initialized because it needs to be set early enough. + // Debug builds also check that it's never accessed before the static + // initialization actually occured, which could be the case if some other + // static initializer ended up calling into DMD. + class Singleton { + public: + Singleton() + : mValue(ReplaceMalloc::GetDMDFuncs()) +# ifdef DEBUG + , + mInitialized(true) +# endif + { + } + + DMDFuncs* Get() { + MOZ_ASSERT(mInitialized); + return mValue; + } + + private: + DMDFuncs* mValue; +# ifdef DEBUG + bool mInitialized; +# endif + }; + + // This singleton pointer must be defined on the program side. In Gecko, + // this is done in xpcom/base/nsMemoryInfoDumper.cpp. + static /* DMDFuncs:: */ Singleton sSingleton; +#endif +}; + +#ifndef REPLACE_MALLOC_IMPL +// Mark a heap block as reported by a memory reporter. +inline void Report(const void* aPtr) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->Report(aPtr); + } +} + +// Mark a heap block as reported immediately on allocation. +inline void ReportOnAlloc(const void* aPtr) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->ReportOnAlloc(aPtr); + } +} + +// Clears existing reportedness data from any prior runs of the memory +// reporters. The following sequence should be used. +// - ClearReports() +// - run the memory reporters +// - Analyze() +// This sequence avoids spurious twice-reported warnings. +inline void ClearReports() { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->ClearReports(); + } +} + +// Determines which heap blocks have been reported, and dumps JSON output +// (via |aWriter|) describing the heap. +// +// The following sample output contains comments that explain the format and +// design choices. The output files can be quite large, so a number of +// decisions were made to minimize size, such as using short property names and +// omitting properties whenever possible. +// +// { +// // The version number of the format, which will be incremented each time +// // backwards-incompatible changes are made. A mandatory integer. +// // +// // Version history: +// // - 1: Bug 1044709 +// // - 2: Bug 1094552 +// // - 3: Bug 1100851 +// // - 4: Bug 1121830 +// // - 5: Bug 1253512 +// "version": 5, +// +// // Information about how DMD was invoked. A mandatory object. +// "invocation": { +// // The contents of the $DMD environment variable. A string, or |null| if +// // $DMD is undefined. +// "dmdEnvVar": "--mode=dark-matter", +// +// // The profiling mode. A mandatory string taking one of the following +// // values: "live", "dark-matter", "cumulative", "scan". +// "mode": "dark-matter", +// }, +// +// // Details of all analyzed heap blocks. A mandatory array. +// "blockList": [ +// // An example of a heap block. +// { +// // Requested size, in bytes. This is a mandatory integer. +// "req": 3584, +// +// // Requested slop size, in bytes. This is mandatory if it is non-zero, +// // but omitted otherwise. +// "slop": 512, +// +// // The stack trace at which the block was allocated. An optional +// // string that indexes into the "traceTable" object. If omitted, no +// // allocation stack trace was recorded for the block. +// "alloc": "A", +// +// // One or more stack traces at which this heap block was reported by a +// // memory reporter. An optional array that will only be present in +// // "dark-matter" mode. The elements are strings that index into +// // the "traceTable" object. +// "reps": ["B"] +// +// // The number of heap blocks with exactly the above properties. This +// // is mandatory if it is greater than one, but omitted otherwise. +// // (Blocks with identical properties don't have to be aggregated via +// // this property, but it can greatly reduce output file size.) +// "num": 5, +// +// // The address of the block. This is mandatory in "scan" mode, but +// // omitted otherwise. +// "addr": "4e4e4e4e", +// +// // The contents of the block, read one word at a time. This is +// // mandatory in "scan" mode for blocks at least one word long, but +// // omitted otherwise. +// "contents": ["0", "6", "7f7f7f7f", "0"] +// } +// ], +// +// // The stack traces referenced by elements of the "blockList" array. This +// // could be an array, but making it an object makes it easier to see +// // which stacks correspond to which references in the "blockList" array. +// "traceTable": { +// // Each property corresponds to a stack trace mentioned in the "blocks" +// // object. Each element is an index into the "frameTable" object. +// "A": ["D", "E"], +// "B": ["F", "G"] +// }, +// +// // The stack frames referenced by the "traceTable" object. The +// // descriptions can be quite long, so they are stored separately from the +// // "traceTable" object so that each one only has to be written once. +// // This could also be an array, but again, making it an object makes it +// // easier to see which frames correspond to which references in the +// // "traceTable" object. +// "frameTable": { +// // Each property key is a frame key mentioned in the "traceTable" object. +// // Each property value is a string containing a frame description. Each +// // frame description must be in a format recognized by `fix_stacks.py`, +// // which requires a frame number at the start. Because each stack frame +// // description in this table can be shared between multiple stack +// // traces, we use a dummy value of #00. The proper frame number can be +// // reconstructed later by scripts that output stack traces in a +// // conventional non-shared format. +// "D": "#00: foo (Foo.cpp:123)", +// "E": "#00: bar (Bar.cpp:234)", +// "F": "#00: baz (Baz.cpp:345)", +// "G": "#00: quux (Quux.cpp:456)" +// } +// } +// +// Implementation note: normally, this function wouldn't be templated, but in +// that case, the function is compiled, which makes the destructor for the +// UniquePtr fire up, and that needs JSONWriteFunc to be fully defined. That, +// in turn, requires to include JSONWriter.h, which includes +// double-conversion.h, which ends up breaking various things built with +// -Werror for various reasons. +// +template <typename JSONWriteFunc> +inline void Analyze(UniquePtr<JSONWriteFunc> aWriteFunc) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->Analyze(std::move(aWriteFunc)); + } +} + +// Gets the size of various data structures. Used to implement a memory +// reporter for DMD. +inline void SizeOf(Sizes* aSizes) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->SizeOf(aSizes); + } +} + +// Prints a status message prefixed with "DMD[<pid>]". Use sparingly. +MOZ_FORMAT_PRINTF(1, 2) +inline void StatusMsg(const char* aFmt, ...) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + va_list ap; + va_start(ap, aFmt); + funcs->StatusMsg(aFmt, ap); + va_end(ap); + } +} + +// Indicates whether or not DMD is running. +inline bool IsRunning() { return !!DMDFuncs::Get(); } + +// Resets all DMD options and then sets new ones according to those specified +// in |aOptions|. Also clears all recorded data about allocations. Only used +// for testing purposes. +inline void ResetEverything(const char* aOptions) { + DMDFuncs* funcs = DMDFuncs::Get(); + if (funcs) { + funcs->ResetEverything(aOptions); + } +} +#endif + +} // namespace dmd +} // namespace mozilla + +#endif /* DMD_h___ */ |