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Diffstat (limited to 'js/src/wasm/WasmDebug.h')
| -rw-r--r-- | js/src/wasm/WasmDebug.h | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/js/src/wasm/WasmDebug.h b/js/src/wasm/WasmDebug.h new file mode 100644 index 0000000000..35c8a838ed --- /dev/null +++ b/js/src/wasm/WasmDebug.h @@ -0,0 +1,187 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * + * Copyright 2016 Mozilla Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef wasm_debug_h +#define wasm_debug_h + +#include "js/HashTable.h" +#include "wasm/WasmCode.h" +#include "wasm/WasmCodegenTypes.h" +#include "wasm/WasmConstants.h" +#include "wasm/WasmExprType.h" +#include "wasm/WasmModule.h" +#include "wasm/WasmTypeDecls.h" +#include "wasm/WasmValType.h" + +namespace js { + +class Debugger; +class WasmBreakpointSite; +class WasmInstanceObject; + +namespace wasm { + +struct MetadataTier; + +// The generated source location for the AST node/expression. The offset field +// refers an offset in an binary format file. + +struct ExprLoc { + uint32_t lineno; + uint32_t column; + uint32_t offset; + ExprLoc() : lineno(0), column(0), offset(0) {} + ExprLoc(uint32_t lineno_, uint32_t column_, uint32_t offset_) + : lineno(lineno_), column(column_), offset(offset_) {} +}; + +using StepperCounters = + HashMap<uint32_t, uint32_t, DefaultHasher<uint32_t>, SystemAllocPolicy>; +using WasmBreakpointSiteMap = + HashMap<uint32_t, WasmBreakpointSite*, DefaultHasher<uint32_t>, + SystemAllocPolicy>; + +/* + * [SMDOC] Wasm debug traps + * + * There is a single debug trap handler for the process, WasmHandleDebugTrap in + * WasmBuiltins.cpp. That function is invoked through the Debug Trap Stub, + * generated by GenerateDebugTrapStub in WasmStubs.cpp. When any function in an + * instance needs to trap for any reason (enter frame, leave frame, breakpoint, + * or single-stepping) then a pointer to the Debug Trap Stub is installed in the + * Instance. Debug-enabled code will look for this pointer and call it if it is + * not null. + * + * WasmHandleDebugTrap may therefore be called very frequently when any function + * in the instance is being debugged, and must filter the trap against the + * tables in the DebugState. It can make use of the return address for the + * call, which identifies the site uniquely. + * + * In order to greatly reduce the frequency of calls to the Debug Trap Stub, an + * array of flag bits, one per function, is attached to the instance. The code + * at the breakable point calls a shared stub within the function containing the + * breakable point to check whether the bit is set for the function. If it is + * not set, the stub can return to its caller immediately; if the bit is set, + * the stub will jump to the installed Debug Trap Stub. + */ + +class DebugState { + const SharedCode code_; + const SharedModule module_; + + // State maintained when debugging is enabled. + + bool enterFrameTrapsEnabled_; + uint32_t enterAndLeaveFrameTrapsCounter_; + WasmBreakpointSiteMap breakpointSites_; + StepperCounters stepperCounters_; + + void enableDebuggingForFunction(Instance* instance, uint32_t funcIndex); + void disableDebuggingForFunction(Instance* instance, uint32_t funcIndex); + void enableDebugTrap(Instance* instance); + void disableDebugTrap(Instance* instance); + + public: + DebugState(const Code& code, const Module& module); + + void trace(JSTracer* trc); + void finalize(JS::GCContext* gcx); + + const Bytes& bytecode() const { return module_->debugBytecode(); } + + [[nodiscard]] bool getLineOffsets(size_t lineno, Vector<uint32_t>* offsets); + [[nodiscard]] bool getAllColumnOffsets(Vector<ExprLoc>* offsets); + [[nodiscard]] bool getOffsetLocation(uint32_t offset, size_t* lineno, + size_t* column); + + // The Code can track enter/leave frame events. Any such event triggers + // debug trap. The enter/leave frame events enabled or disabled across + // all functions. + + void adjustEnterAndLeaveFrameTrapsState(JSContext* cx, Instance* instance, + bool enabled); + void ensureEnterFrameTrapsState(JSContext* cx, Instance* instance, + bool enabled); + bool enterFrameTrapsEnabled() const { return enterFrameTrapsEnabled_; } + + // When the Code is debugEnabled, individual breakpoints can be enabled or + // disabled at instruction offsets. + + bool hasBreakpointTrapAtOffset(uint32_t offset); + void toggleBreakpointTrap(JSRuntime* rt, Instance* instance, uint32_t offset, + bool enabled); + WasmBreakpointSite* getBreakpointSite(uint32_t offset) const; + WasmBreakpointSite* getOrCreateBreakpointSite(JSContext* cx, + Instance* instance, + uint32_t offset); + bool hasBreakpointSite(uint32_t offset); + void destroyBreakpointSite(JS::GCContext* gcx, Instance* instance, + uint32_t offset); + void clearBreakpointsIn(JS::GCContext* gcx, WasmInstanceObject* instance, + js::Debugger* dbg, JSObject* handler); + + // When the Code is debug-enabled, single-stepping mode can be toggled on + // the granularity of individual functions. + + bool stepModeEnabled(uint32_t funcIndex) const; + [[nodiscard]] bool incrementStepperCount(JSContext* cx, Instance* instance, + uint32_t funcIndex); + void decrementStepperCount(JS::GCContext* gcx, Instance* instance, + uint32_t funcIndex); + + // Stack inspection helpers. + + [[nodiscard]] bool debugGetLocalTypes(uint32_t funcIndex, + ValTypeVector* locals, + size_t* argsLength, + StackResults* stackResults); + [[nodiscard]] bool getGlobal(Instance& instance, uint32_t globalIndex, + MutableHandleValue vp); + + // Debug URL helpers. + + [[nodiscard]] bool getSourceMappingURL(JSContext* cx, + MutableHandleString result) const; + + // Accessors for commonly used elements of linked structures. + + const MetadataTier& metadata(Tier t) const { return code_->metadata(t); } + const Metadata& metadata() const { return code_->metadata(); } + const CodeRangeVector& codeRanges(Tier t) const { + return metadata(t).codeRanges; + } + const CallSiteVector& callSites(Tier t) const { + return metadata(t).callSites; + } + + uint32_t funcToCodeRangeIndex(uint32_t funcIndex) const { + return metadata(Tier::Debug).funcToCodeRange[funcIndex]; + } + + // about:memory reporting: + + void addSizeOfMisc(MallocSizeOf mallocSizeOf, Metadata::SeenSet* seenMetadata, + Code::SeenSet* seenCode, size_t* code, size_t* data) const; +}; + +using UniqueDebugState = UniquePtr<DebugState>; + +} // namespace wasm +} // namespace js + +#endif // wasm_debug_h |