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+/* -*- 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 <string.h>
+#include <stdarg.h>
+
+#include "mozilla/DebugOnly.h"
+#include "mozilla/Move.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);
+
+ 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 the stack-fixing
+// // scripts (e.g. fix_linux_stack.py), which require 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(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.
+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___ */