summaryrefslogtreecommitdiffstats
path: root/js/src/vm/Stack.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'js/src/vm/Stack.cpp')
-rw-r--r--js/src/vm/Stack.cpp784
1 files changed, 784 insertions, 0 deletions
diff --git a/js/src/vm/Stack.cpp b/js/src/vm/Stack.cpp
new file mode 100644
index 0000000000..ffbe88147d
--- /dev/null
+++ b/js/src/vm/Stack.cpp
@@ -0,0 +1,784 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=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/. */
+
+#include "vm/Stack-inl.h"
+
+#include "mozilla/Maybe.h" // mozilla::Maybe
+
+#include <algorithm> // std::max
+#include <iterator> // std::size
+#include <stddef.h> // size_t
+#include <stdint.h> // uint8_t, uint32_t
+
+#include "gc/Tracer.h" // js::TraceRoot
+#include "jit/JitcodeMap.h"
+#include "jit/JitRuntime.h"
+#include "js/friend/ErrorMessages.h" // JSMSG_*
+#include "js/Value.h" // JS::Value
+#include "vm/FrameIter.h" // js::FrameIter
+#include "vm/JSContext.h"
+#include "wasm/WasmProcess.h"
+
+#include "jit/JSJitFrameIter-inl.h"
+#include "vm/Probes-inl.h"
+
+using namespace js;
+
+using mozilla::Maybe;
+
+using JS::Value;
+
+/*****************************************************************************/
+
+void InterpreterFrame::initExecuteFrame(JSContext* cx, HandleScript script,
+ AbstractFramePtr evalInFramePrev,
+ HandleObject envChain) {
+ flags_ = 0;
+ script_ = script;
+
+ envChain_ = envChain.get();
+ prev_ = nullptr;
+ prevpc_ = nullptr;
+ prevsp_ = nullptr;
+
+ evalInFramePrev_ = evalInFramePrev;
+ MOZ_ASSERT_IF(evalInFramePrev, isDebuggerEvalFrame());
+
+ if (script->isDebuggee()) {
+ setIsDebuggee();
+ }
+
+#ifdef DEBUG
+ Debug_SetValueRangeToCrashOnTouch(&rval_, 1);
+#endif
+}
+
+ArrayObject* InterpreterFrame::createRestParameter(JSContext* cx) {
+ MOZ_ASSERT(script()->hasRest());
+ unsigned nformal = callee().nargs() - 1, nactual = numActualArgs();
+ unsigned nrest = (nactual > nformal) ? nactual - nformal : 0;
+ Value* restvp = argv() + nformal;
+ return NewDenseCopiedArray(cx, nrest, restvp);
+}
+
+static inline void AssertScopeMatchesEnvironment(Scope* scope,
+ JSObject* originalEnv) {
+#ifdef DEBUG
+ JSObject* env = originalEnv;
+ for (ScopeIter si(scope); si; si++) {
+ if (si.kind() == ScopeKind::NonSyntactic) {
+ while (env->is<WithEnvironmentObject>() ||
+ env->is<NonSyntacticVariablesObject>() ||
+ (env->is<LexicalEnvironmentObject>() &&
+ !env->as<LexicalEnvironmentObject>().isSyntactic())) {
+ MOZ_ASSERT(!IsSyntacticEnvironment(env));
+ env = &env->as<EnvironmentObject>().enclosingEnvironment();
+ }
+ } else if (si.hasSyntacticEnvironment()) {
+ switch (si.kind()) {
+ case ScopeKind::Function:
+ MOZ_ASSERT(env->as<CallObject>()
+ .callee()
+ .maybeCanonicalFunction()
+ ->nonLazyScript() ==
+ si.scope()->as<FunctionScope>().script());
+ env = &env->as<CallObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::FunctionBodyVar:
+ MOZ_ASSERT(&env->as<VarEnvironmentObject>().scope() == si.scope());
+ env = &env->as<VarEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::Lexical:
+ case ScopeKind::SimpleCatch:
+ case ScopeKind::Catch:
+ case ScopeKind::NamedLambda:
+ case ScopeKind::StrictNamedLambda:
+ case ScopeKind::FunctionLexical:
+ case ScopeKind::ClassBody:
+ MOZ_ASSERT(&env->as<ScopedLexicalEnvironmentObject>().scope() ==
+ si.scope());
+ env =
+ &env->as<ScopedLexicalEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::With:
+ MOZ_ASSERT(&env->as<WithEnvironmentObject>().scope() == si.scope());
+ env = &env->as<WithEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::Eval:
+ case ScopeKind::StrictEval:
+ env = &env->as<VarEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::Global:
+ env =
+ &env->as<GlobalLexicalEnvironmentObject>().enclosingEnvironment();
+ MOZ_ASSERT(env->is<GlobalObject>());
+ break;
+
+ case ScopeKind::NonSyntactic:
+ MOZ_CRASH("NonSyntactic should not have a syntactic environment");
+ break;
+
+ case ScopeKind::Module:
+ MOZ_ASSERT(&env->as<ModuleEnvironmentObject>().module() ==
+ si.scope()->as<ModuleScope>().module());
+ env = &env->as<ModuleEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::WasmInstance:
+ env =
+ &env->as<WasmInstanceEnvironmentObject>().enclosingEnvironment();
+ break;
+
+ case ScopeKind::WasmFunction:
+ env = &env->as<WasmFunctionCallObject>().enclosingEnvironment();
+ break;
+ }
+ }
+ }
+
+ // In the case of a non-syntactic env chain, the immediate parent of the
+ // outermost non-syntactic env may be the global lexical env, or, if
+ // called from Debugger, a DebugEnvironmentProxy.
+ //
+ // In the case of a syntactic env chain, the outermost env is always a
+ // GlobalObject.
+ MOZ_ASSERT(env->is<GlobalObject>() || IsGlobalLexicalEnvironment(env) ||
+ env->is<DebugEnvironmentProxy>());
+#endif
+}
+
+static inline void AssertScopeMatchesEnvironment(InterpreterFrame* fp,
+ jsbytecode* pc) {
+#ifdef DEBUG
+ // If we OOMed before fully initializing the environment chain, the scope
+ // and environment will definitely mismatch.
+ if (fp->script()->initialEnvironmentShape() && fp->hasInitialEnvironment()) {
+ AssertScopeMatchesEnvironment(fp->script()->innermostScope(pc),
+ fp->environmentChain());
+ }
+#endif
+}
+
+bool InterpreterFrame::initFunctionEnvironmentObjects(JSContext* cx) {
+ return js::InitFunctionEnvironmentObjects(cx, this);
+}
+
+bool InterpreterFrame::prologue(JSContext* cx) {
+ RootedScript script(cx, this->script());
+
+ MOZ_ASSERT(cx->interpreterRegs().pc == script->code());
+ MOZ_ASSERT(cx->realm() == script->realm());
+
+ if (!isFunctionFrame()) {
+ return probes::EnterScript(cx, script, nullptr, this);
+ }
+
+ // At this point, we've yet to push any environments. Check that they
+ // match the enclosing scope.
+ AssertScopeMatchesEnvironment(script->enclosingScope(), environmentChain());
+
+ if (callee().needsFunctionEnvironmentObjects() &&
+ !initFunctionEnvironmentObjects(cx)) {
+ return false;
+ }
+
+ MOZ_ASSERT_IF(isConstructing(),
+ thisArgument().isObject() ||
+ thisArgument().isMagic(JS_UNINITIALIZED_LEXICAL));
+
+ return probes::EnterScript(cx, script, script->function(), this);
+}
+
+void InterpreterFrame::epilogue(JSContext* cx, jsbytecode* pc) {
+ RootedScript script(cx, this->script());
+ MOZ_ASSERT(cx->realm() == script->realm());
+ probes::ExitScript(cx, script, script->function(),
+ hasPushedGeckoProfilerFrame());
+
+ // Check that the scope matches the environment at the point of leaving
+ // the frame.
+ AssertScopeMatchesEnvironment(this, pc);
+
+ EnvironmentIter ei(cx, this, pc);
+ UnwindAllEnvironmentsInFrame(cx, ei);
+
+ if (isFunctionFrame()) {
+ if (!callee().isGenerator() && !callee().isAsync() && isConstructing() &&
+ thisArgument().isObject() && returnValue().isPrimitive()) {
+ setReturnValue(thisArgument());
+ }
+
+ return;
+ }
+
+ MOZ_ASSERT(isEvalFrame() || isGlobalFrame() || isModuleFrame());
+}
+
+bool InterpreterFrame::checkReturn(JSContext* cx, HandleValue thisv,
+ MutableHandleValue result) {
+ MOZ_ASSERT(script()->isDerivedClassConstructor());
+ MOZ_ASSERT(isFunctionFrame());
+ MOZ_ASSERT(callee().isClassConstructor());
+
+ HandleValue retVal = returnValue();
+ if (retVal.isObject()) {
+ result.set(retVal);
+ return true;
+ }
+
+ if (!retVal.isUndefined()) {
+ ReportValueError(cx, JSMSG_BAD_DERIVED_RETURN, JSDVG_IGNORE_STACK, retVal,
+ nullptr);
+ return false;
+ }
+
+ if (thisv.isMagic(JS_UNINITIALIZED_LEXICAL)) {
+ return ThrowUninitializedThis(cx);
+ }
+
+ result.set(thisv);
+ return true;
+}
+
+bool InterpreterFrame::pushVarEnvironment(JSContext* cx, Handle<Scope*> scope) {
+ return js::PushVarEnvironmentObject(cx, scope, this);
+}
+
+bool InterpreterFrame::pushLexicalEnvironment(JSContext* cx,
+ Handle<LexicalScope*> scope) {
+ BlockLexicalEnvironmentObject* env =
+ BlockLexicalEnvironmentObject::createForFrame(cx, scope, this);
+ if (!env) {
+ return false;
+ }
+
+ pushOnEnvironmentChain(*env);
+ return true;
+}
+
+bool InterpreterFrame::freshenLexicalEnvironment(JSContext* cx,
+ jsbytecode* pc) {
+ Rooted<BlockLexicalEnvironmentObject*> env(
+ cx, &envChain_->as<BlockLexicalEnvironmentObject>());
+ BlockLexicalEnvironmentObject* fresh =
+ BlockLexicalEnvironmentObject::clone(cx, env);
+ if (!fresh) {
+ return false;
+ }
+
+ if (MOZ_UNLIKELY(cx->realm()->isDebuggee())) {
+ Rooted<BlockLexicalEnvironmentObject*> freshRoot(cx, fresh);
+ DebugEnvironments::onPopLexical(cx, this, pc);
+ fresh = freshRoot;
+ }
+
+ replaceInnermostEnvironment(*fresh);
+ return true;
+}
+
+bool InterpreterFrame::recreateLexicalEnvironment(JSContext* cx,
+ jsbytecode* pc) {
+ Rooted<BlockLexicalEnvironmentObject*> env(
+ cx, &envChain_->as<BlockLexicalEnvironmentObject>());
+ BlockLexicalEnvironmentObject* fresh =
+ BlockLexicalEnvironmentObject::recreate(cx, env);
+ if (!fresh) {
+ return false;
+ }
+
+ if (MOZ_UNLIKELY(cx->realm()->isDebuggee())) {
+ Rooted<BlockLexicalEnvironmentObject*> freshRoot(cx, fresh);
+ DebugEnvironments::onPopLexical(cx, this, pc);
+ fresh = freshRoot;
+ }
+
+ replaceInnermostEnvironment(*fresh);
+ return true;
+}
+
+bool InterpreterFrame::pushClassBodyEnvironment(JSContext* cx,
+ Handle<ClassBodyScope*> scope) {
+ ClassBodyLexicalEnvironmentObject* env =
+ ClassBodyLexicalEnvironmentObject::createForFrame(cx, scope, this);
+ if (!env) {
+ return false;
+ }
+
+ pushOnEnvironmentChain(*env);
+ return true;
+}
+
+void InterpreterFrame::trace(JSTracer* trc, Value* sp, jsbytecode* pc) {
+ TraceRoot(trc, &envChain_, "env chain");
+ TraceRoot(trc, &script_, "script");
+
+ if (flags_ & HAS_ARGS_OBJ) {
+ TraceRoot(trc, &argsObj_, "arguments");
+ }
+
+ if (hasReturnValue()) {
+ TraceRoot(trc, &rval_, "rval");
+ }
+
+ MOZ_ASSERT(sp >= slots());
+
+ if (hasArgs()) {
+ // Trace the callee and |this|. When we're doing a moving GC, we
+ // need to fix up the callee pointer before we use it below, under
+ // numFormalArgs() and script().
+ TraceRootRange(trc, 2, argv_ - 2, "fp callee and this");
+
+ // Trace arguments.
+ unsigned argc = std::max(numActualArgs(), numFormalArgs());
+ TraceRootRange(trc, argc + isConstructing(), argv_, "fp argv");
+ }
+
+ JSScript* script = this->script();
+ size_t nfixed = script->nfixed();
+ size_t nlivefixed = script->calculateLiveFixed(pc);
+
+ if (nfixed == nlivefixed) {
+ // All locals are live.
+ traceValues(trc, 0, sp - slots());
+ } else {
+ // Trace operand stack.
+ traceValues(trc, nfixed, sp - slots());
+
+ // Clear dead block-scoped locals.
+ while (nfixed > nlivefixed) {
+ unaliasedLocal(--nfixed).setUndefined();
+ }
+
+ // Trace live locals.
+ traceValues(trc, 0, nlivefixed);
+ }
+
+ if (auto* debugEnvs = script->realm()->debugEnvs()) {
+ debugEnvs->traceLiveFrame(trc, this);
+ }
+}
+
+void InterpreterFrame::traceValues(JSTracer* trc, unsigned start,
+ unsigned end) {
+ if (start < end) {
+ TraceRootRange(trc, end - start, slots() + start, "vm_stack");
+ }
+}
+
+static void TraceInterpreterActivation(JSTracer* trc,
+ InterpreterActivation* act) {
+ for (InterpreterFrameIterator frames(act); !frames.done(); ++frames) {
+ InterpreterFrame* fp = frames.frame();
+ fp->trace(trc, frames.sp(), frames.pc());
+ }
+}
+
+void js::TraceInterpreterActivations(JSContext* cx, JSTracer* trc) {
+ for (ActivationIterator iter(cx); !iter.done(); ++iter) {
+ Activation* act = iter.activation();
+ if (act->isInterpreter()) {
+ TraceInterpreterActivation(trc, act->asInterpreter());
+ }
+ }
+}
+
+/*****************************************************************************/
+
+// Unlike the other methods of this class, this method is defined here so that
+// we don't have to #include jsautooplen.h in vm/Stack.h.
+void InterpreterRegs::setToEndOfScript() { sp = fp()->base(); }
+
+/*****************************************************************************/
+
+InterpreterFrame* InterpreterStack::pushInvokeFrame(
+ JSContext* cx, const CallArgs& args, MaybeConstruct constructing) {
+ LifoAlloc::Mark mark = allocator_.mark();
+
+ RootedFunction fun(cx, &args.callee().as<JSFunction>());
+ RootedScript script(cx, fun->nonLazyScript());
+
+ Value* argv;
+ InterpreterFrame* fp = getCallFrame(cx, args, script, constructing, &argv);
+ if (!fp) {
+ return nullptr;
+ }
+
+ fp->mark_ = mark;
+ fp->initCallFrame(nullptr, nullptr, nullptr, *fun, script, argv,
+ args.length(), constructing);
+ return fp;
+}
+
+InterpreterFrame* InterpreterStack::pushExecuteFrame(
+ JSContext* cx, HandleScript script, HandleObject envChain,
+ AbstractFramePtr evalInFrame) {
+ LifoAlloc::Mark mark = allocator_.mark();
+
+ unsigned nvars = script->nslots();
+ uint8_t* buffer =
+ allocateFrame(cx, sizeof(InterpreterFrame) + nvars * sizeof(Value));
+ if (!buffer) {
+ return nullptr;
+ }
+
+ InterpreterFrame* fp = reinterpret_cast<InterpreterFrame*>(buffer);
+ fp->mark_ = mark;
+ fp->initExecuteFrame(cx, script, evalInFrame, envChain);
+ fp->initLocals();
+
+ return fp;
+}
+
+/*****************************************************************************/
+
+InterpreterFrameIterator& InterpreterFrameIterator::operator++() {
+ MOZ_ASSERT(!done());
+ if (fp_ != activation_->entryFrame_) {
+ pc_ = fp_->prevpc();
+ sp_ = fp_->prevsp();
+ fp_ = fp_->prev();
+ } else {
+ pc_ = nullptr;
+ sp_ = nullptr;
+ fp_ = nullptr;
+ }
+ return *this;
+}
+
+JS::ProfilingFrameIterator::ProfilingFrameIterator(
+ JSContext* cx, const RegisterState& state,
+ const Maybe<uint64_t>& samplePositionInProfilerBuffer)
+ : cx_(cx),
+ samplePositionInProfilerBuffer_(samplePositionInProfilerBuffer),
+ activation_(nullptr) {
+ if (!cx->runtime()->geckoProfiler().enabled()) {
+ MOZ_CRASH(
+ "ProfilingFrameIterator called when geckoProfiler not enabled for "
+ "runtime.");
+ }
+
+ if (!cx->profilingActivation()) {
+ return;
+ }
+
+ // If profiler sampling is not enabled, skip.
+ if (!cx->isProfilerSamplingEnabled()) {
+ return;
+ }
+
+ activation_ = cx->profilingActivation();
+
+ MOZ_ASSERT(activation_->isProfiling());
+
+ static_assert(sizeof(wasm::ProfilingFrameIterator) <= StorageSpace &&
+ sizeof(jit::JSJitProfilingFrameIterator) <= StorageSpace,
+ "ProfilingFrameIterator::storage_ is too small");
+ static_assert(alignof(void*) >= alignof(wasm::ProfilingFrameIterator) &&
+ alignof(void*) >= alignof(jit::JSJitProfilingFrameIterator),
+ "ProfilingFrameIterator::storage_ is too weakly aligned");
+
+ iteratorConstruct(state);
+ settle();
+}
+
+JS::ProfilingFrameIterator::~ProfilingFrameIterator() {
+ if (!done()) {
+ MOZ_ASSERT(activation_->isProfiling());
+ iteratorDestroy();
+ }
+}
+
+void JS::ProfilingFrameIterator::operator++() {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+ if (isWasm()) {
+ ++wasmIter();
+ } else {
+ ++jsJitIter();
+ }
+ settle();
+}
+
+void JS::ProfilingFrameIterator::settleFrames() {
+ // Handle transition frames (see comment in JitFrameIter::operator++).
+ if (isJSJit() && !jsJitIter().done() &&
+ jsJitIter().frameType() == jit::FrameType::WasmToJSJit) {
+ wasm::Frame* fp = (wasm::Frame*)jsJitIter().fp();
+ iteratorDestroy();
+ new (storage()) wasm::ProfilingFrameIterator(fp);
+ kind_ = Kind::Wasm;
+ MOZ_ASSERT(!wasmIter().done());
+ maybeSetEndStackAddress(wasmIter().endStackAddress());
+ return;
+ }
+
+ if (isWasm() && wasmIter().done() && wasmIter().unwoundJitCallerFP()) {
+ uint8_t* fp = wasmIter().unwoundJitCallerFP();
+ iteratorDestroy();
+ // Using this ctor will skip the first jit->wasm frame, which is
+ // needed because the profiling iterator doesn't know how to unwind
+ // when the callee has no script.
+ new (storage())
+ jit::JSJitProfilingFrameIterator((jit::CommonFrameLayout*)fp);
+ kind_ = Kind::JSJit;
+ MOZ_ASSERT(!jsJitIter().done());
+ maybeSetEndStackAddress(jsJitIter().endStackAddress());
+ return;
+ }
+}
+
+void JS::ProfilingFrameIterator::settle() {
+ settleFrames();
+ while (iteratorDone()) {
+ iteratorDestroy();
+ activation_ = activation_->prevProfiling();
+ endStackAddress_ = nullptr;
+ if (!activation_) {
+ return;
+ }
+ iteratorConstruct();
+ settleFrames();
+ }
+}
+
+void JS::ProfilingFrameIterator::iteratorConstruct(const RegisterState& state) {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+
+ jit::JitActivation* activation = activation_->asJit();
+
+ // We want to know if we should start with a wasm profiling frame iterator
+ // or not. To determine this, there are three possibilities:
+ // - we've exited to C++ from wasm, in which case the activation
+ // exitFP low bit is tagged and we can test hasWasmExitFP().
+ // - we're in wasm code, so we can do a lookup on PC.
+ // - in all the other cases, we're not in wasm or we haven't exited from
+ // wasm.
+ if (activation->hasWasmExitFP() || wasm::InCompiledCode(state.pc)) {
+ new (storage()) wasm::ProfilingFrameIterator(*activation, state);
+ kind_ = Kind::Wasm;
+ maybeSetEndStackAddress(wasmIter().endStackAddress());
+ return;
+ }
+
+ new (storage()) jit::JSJitProfilingFrameIterator(cx_, state.pc, state.sp);
+ kind_ = Kind::JSJit;
+ maybeSetEndStackAddress(jsJitIter().endStackAddress());
+}
+
+void JS::ProfilingFrameIterator::iteratorConstruct() {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+
+ jit::JitActivation* activation = activation_->asJit();
+
+ // The same reasoning as in the above iteratorConstruct variant applies
+ // here, except that it's even simpler: since this activation is higher up
+ // on the stack, it can only have exited to C++, through wasm or ion.
+ if (activation->hasWasmExitFP()) {
+ new (storage()) wasm::ProfilingFrameIterator(*activation);
+ kind_ = Kind::Wasm;
+ maybeSetEndStackAddress(wasmIter().endStackAddress());
+ return;
+ }
+
+ auto* fp = (jit::ExitFrameLayout*)activation->jsExitFP();
+ new (storage()) jit::JSJitProfilingFrameIterator(fp);
+ kind_ = Kind::JSJit;
+ maybeSetEndStackAddress(jsJitIter().endStackAddress());
+}
+
+void JS::ProfilingFrameIterator::iteratorDestroy() {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+
+ if (isWasm()) {
+ wasmIter().~ProfilingFrameIterator();
+ return;
+ }
+
+ jsJitIter().~JSJitProfilingFrameIterator();
+}
+
+bool JS::ProfilingFrameIterator::iteratorDone() {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+
+ if (isWasm()) {
+ return wasmIter().done();
+ }
+
+ return jsJitIter().done();
+}
+
+void* JS::ProfilingFrameIterator::stackAddress() const {
+ MOZ_ASSERT(!done());
+ MOZ_ASSERT(activation_->isJit());
+
+ if (isWasm()) {
+ return wasmIter().stackAddress();
+ }
+
+ return jsJitIter().stackAddress();
+}
+
+Maybe<JS::ProfilingFrameIterator::Frame>
+JS::ProfilingFrameIterator::getPhysicalFrameAndEntry(
+ const jit::JitcodeGlobalEntry** entry) const {
+ *entry = nullptr;
+
+ void* stackAddr = stackAddress();
+
+ MOZ_DIAGNOSTIC_ASSERT(endStackAddress_);
+ MOZ_DIAGNOSTIC_ASSERT(stackAddr >= endStackAddress_);
+
+ if (isWasm()) {
+ Frame frame;
+ frame.kind = Frame_Wasm;
+ frame.stackAddress = stackAddr;
+ frame.returnAddress_ = nullptr;
+ frame.activation = activation_;
+ frame.label = nullptr;
+ frame.endStackAddress = endStackAddress_;
+ frame.interpreterScript = nullptr;
+ // TODO: get the realm ID of wasm frames. Bug 1596235.
+ frame.realmID = 0;
+ return mozilla::Some(frame);
+ }
+
+ MOZ_ASSERT(isJSJit());
+
+ if (jit::IsPortableBaselineInterpreterEnabled()) {
+ return mozilla::Nothing();
+ }
+
+ // Look up an entry for the return address.
+ void* returnAddr = jsJitIter().resumePCinCurrentFrame();
+ jit::JitcodeGlobalTable* table =
+ cx_->runtime()->jitRuntime()->getJitcodeGlobalTable();
+
+ // NB:
+ // The following lookups should be infallible, but the ad-hoc stackwalking
+ // code rots easily and corner cases where frames can't be looked up
+ // occur too often (e.g. once every day).
+ //
+ // The calls to `lookup*` below have been changed from infallible ones to
+ // fallible ones. The proper solution to this problem is to fix all
+ // the jitcode to use frame-pointers and reliably walk the stack with those.
+ if (samplePositionInProfilerBuffer_) {
+ *entry = table->lookupForSampler(returnAddr, cx_->runtime(),
+ *samplePositionInProfilerBuffer_);
+ } else {
+ *entry = table->lookup(returnAddr);
+ }
+
+ // Failed to look up a jitcode entry for the given address, ignore.
+ if (!*entry) {
+ return mozilla::Nothing();
+ }
+
+ // Dummy frames produce no stack frames.
+ if ((*entry)->isDummy()) {
+ return mozilla::Nothing();
+ }
+
+ Frame frame;
+ if ((*entry)->isBaselineInterpreter()) {
+ frame.kind = Frame_BaselineInterpreter;
+ } else if ((*entry)->isBaseline()) {
+ frame.kind = Frame_Baseline;
+ } else {
+ MOZ_ASSERT((*entry)->isIon() || (*entry)->isIonIC());
+ frame.kind = Frame_Ion;
+ }
+ frame.stackAddress = stackAddr;
+ if ((*entry)->isBaselineInterpreter()) {
+ frame.label = jsJitIter().baselineInterpreterLabel();
+ jsJitIter().baselineInterpreterScriptPC(
+ &frame.interpreterScript, &frame.interpreterPC_, &frame.realmID);
+ MOZ_ASSERT(frame.interpreterScript);
+ MOZ_ASSERT(frame.interpreterPC_);
+ } else {
+ frame.interpreterScript = nullptr;
+ frame.returnAddress_ = returnAddr;
+ frame.label = nullptr;
+ frame.realmID = 0;
+ }
+ frame.activation = activation_;
+ frame.endStackAddress = endStackAddress_;
+ return mozilla::Some(frame);
+}
+
+uint32_t JS::ProfilingFrameIterator::extractStack(Frame* frames,
+ uint32_t offset,
+ uint32_t end) const {
+ if (offset >= end) {
+ return 0;
+ }
+
+ const jit::JitcodeGlobalEntry* entry;
+ Maybe<Frame> physicalFrame = getPhysicalFrameAndEntry(&entry);
+
+ // Dummy frames produce no stack frames.
+ if (physicalFrame.isNothing()) {
+ return 0;
+ }
+
+ if (isWasm()) {
+ frames[offset] = physicalFrame.value();
+ frames[offset].label = wasmIter().label();
+ return 1;
+ }
+
+ if (physicalFrame->kind == Frame_BaselineInterpreter) {
+ frames[offset] = physicalFrame.value();
+ return 1;
+ }
+
+ // Extract the stack for the entry. Assume maximum inlining depth is <64
+ const char* labels[64];
+ uint32_t depth = entry->callStackAtAddr(cx_->runtime(),
+ jsJitIter().resumePCinCurrentFrame(),
+ labels, std::size(labels));
+ MOZ_ASSERT(depth < std::size(labels));
+ for (uint32_t i = 0; i < depth; i++) {
+ if (offset + i >= end) {
+ return i;
+ }
+ frames[offset + i] = physicalFrame.value();
+ frames[offset + i].label = labels[i];
+ }
+
+ return depth;
+}
+
+Maybe<JS::ProfilingFrameIterator::Frame>
+JS::ProfilingFrameIterator::getPhysicalFrameWithoutLabel() const {
+ const jit::JitcodeGlobalEntry* unused;
+ return getPhysicalFrameAndEntry(&unused);
+}
+
+bool JS::ProfilingFrameIterator::isWasm() const {
+ MOZ_ASSERT(!done());
+ return kind_ == Kind::Wasm;
+}
+
+bool JS::ProfilingFrameIterator::isJSJit() const {
+ return kind_ == Kind::JSJit;
+}
+
+mozilla::Maybe<JS::ProfilingFrameIterator::RegisterState>
+JS::ProfilingFrameIterator::getCppEntryRegisters() const {
+ if (!isJSJit()) {
+ return mozilla::Nothing{};
+ }
+ return jit::JitRuntime::getCppEntryRegisters(jsJitIter().framePtr());
+}