Reuse handle-based unwind lookup for WebAssembly

docs/design/datacontracts/ExecutionManager.md

@@ -32,11 +32,6 @@ public struct CodeBlockHandle
     // GetCodeBlockHandle. Other addresses are returned unchanged.
     TargetCodePointer GetDiagnosticCodeStartFromEntryPoint(TargetCodePointer entryPoint);
 
-    // Finds the unwind info for the function containing controlPC without resolving its method.
-    bool TryGetUnwindInfo(
-        TargetCodePointer controlPC,
-        out TargetPointer runtimeFunction,
-        out TargetPointer unwindInfoBaseAddress);
     // Gets the unwind info of the code block at the specified code pointer
     TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle);
     // Gets the base address the UnwindInfo of codeInfoHandle is relative to
@@ -615,9 +610,7 @@ The `GetMethodDesc`, `GetStartAddress`, and `GetRelativeOffset` APIs extract fie
     }
 ```
 
-`IExecutionManager.TryGetUnwindInfo` maps a control PC directly to its Windows-style unwind data in the form of a `RUNTIME_FUNCTION` pointer and the base address to which that entry's relative fields apply. It finds the owning range and delegates to the same per-JIT-manager unwind lookup used by `GetUnwindInfo`, but does not resolve a method or create a `CodeBlockHandle`. It returns false, with both outputs null, when the address has no owning managed range or its code kind has no native unwind information.
-
-`IExecutionManager.GetUnwindInfo` gets the same platform-dependent `RUNTIME_FUNCTION` for an existing `CodeBlockHandle`. The ExecutionManager delegates to the JitManager implementations as the unwind infos are stored differently on jitted and R2R code.
+`IExecutionManager.GetUnwindInfo` gets the platform-dependent `RUNTIME_FUNCTION` for an existing `CodeBlockHandle`. The ExecutionManager delegates to the JitManager implementations as the unwind infos are stored differently on jitted and R2R code.
 
 * For jitted code (`EEJitManager`) a list of sorted `RUNTIME_FUNCTION` are stored on the `RealCodeHeader` which is accessed in the same was as `GetMethodInfo` described above. The correct `RUNTIME_FUNCTION` is found by binary searching the list based on IP.
 

docs/design/datacontracts/StackWalk.md

@@ -486,7 +486,7 @@ Root-method frame identities have three forms:
 
 A funclet instead stores its establishing-frame pointer plus two, giving the identity low bits `10`. These tags are followed until the root-method frame is reached. The physical funclet frame supplies the function-local virtual IP, while the root frame supplies the identity used to find the controlling method's base virtual IP. cDAC requires each establishing-frame link to move toward the caller and bounds the traversal so corrupt target memory cannot create an unbounded walk.
 
-**WASM R2R unwinding.** The virtual IP is the identity-derived method base plus twice the physical frame's stored function-local value. `WasmContext.Unwind` passes its current virtual IP as the control PC to `IExecutionManager.TryGetUnwindInfo`, reads the fixed frame size as a uint32 ULEB128 value from `unwindInfoBaseAddress + RuntimeFunction.UnwindData`, and adds that size to the physical frame base. A zero frame size terminates the R2R walk because it would make no progress; malformed uint32 ULEB128 data is invalid.
+**WASM R2R unwinding.** The virtual IP is the identity-derived method base plus twice the physical frame's stored function-local value. `WasmContext.Unwind` resolves its current virtual IP through `IExecutionManager.GetCodeBlockHandle`, then uses `GetUnwindInfo` and `GetUnwindInfoBaseAddress` to locate the unwind data. It reads the fixed frame size as a uint32 ULEB128 value from `unwindInfoBaseAddress + RuntimeFunction.UnwindData` and adds that size to the physical frame base. A zero frame size terminates the R2R walk because it would make no progress; malformed uint32 ULEB128 data is invalid.
 
 For a managed caller, the resulting stack pointer identifies the caller's R2R frame record; its virtual IP and logical frame pointer are resolved as above. When the current frame has a positive odd reverse-P/Invoke identity, unwinding still preserves the advanced caller SP for the explicit `Frame` chain, but leaves IP and FP null because the caller is native. At a terminator or another non-R2R caller, the R2R context is cleared and walking continues through the explicit `Frame` or interpreter frame chain.
 

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/IExecutionManager.cs

@@ -117,7 +117,6 @@ public interface IExecutionManager : IContract
     TargetCodePointer GetDiagnosticCodeStartFromEntryPoint(TargetCodePointer entryPoint) => throw new NotImplementedException();
     bool IsFunclet(CodeBlockHandle codeInfoHandle) => throw new NotImplementedException();
     bool IsFilterFunclet(CodeBlockHandle codeInfoHandle) => throw new NotImplementedException();
-    bool TryGetUnwindInfo(TargetCodePointer controlPC, out TargetPointer runtimeFunction, out TargetPointer unwindInfoBaseAddress) => throw new NotImplementedException();
     TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle) => throw new NotImplementedException();
     TargetPointer GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle) => throw new NotImplementedException();
     TargetPointer GetDebugInfo(CodeBlockHandle codeInfoHandle, out bool hasFlagByte) => throw new NotImplementedException();

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ExecutionManager/ExecutionManagerCore.cs

@@ -544,50 +544,16 @@ TargetPointer IExecutionManager.GetUnwindInfo(CodeBlockHandle codeInfoHandle)
         return jitManager?.GetUnwindInfo(range, codeInfoHandle.Address.Value) ?? TargetPointer.Null;
     }
 
-    bool IExecutionManager.TryGetUnwindInfo(
-        TargetCodePointer controlPC,
-        out TargetPointer runtimeFunction,
-        out TargetPointer unwindInfoBaseAddress)
-    {
-        runtimeFunction = TargetPointer.Null;
-        unwindInfoBaseAddress = TargetPointer.Null;
-
-        RangeSection range = RangeSection.Find(
-            _target,
-            _topRangeSectionMapAddress,
-            _rangeSectionMapLookup,
-            _virtualIPRangeListAddress,
-            controlPC);
-        if (range.Data is null)
-            return false;
-
-        JitManager? jitManager = GetJitManager(range);
-        if (jitManager is null)
-            return false;
-
-        runtimeFunction = jitManager.GetUnwindInfo(range, controlPC);
-        if (runtimeFunction == TargetPointer.Null)
-            return false;
-
-        unwindInfoBaseAddress = GetUnwindInfoBaseAddress(range);
-        return true;
-    }
-
     TargetPointer IExecutionManager.GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle)
     {
         RangeSection range = RangeSectionFromCodeBlockHandle(codeInfoHandle);
         if (range.Data == null)
             throw new InvalidOperationException($"{nameof(RangeSection)} not found for {codeInfoHandle.Address}");
 
-        return GetUnwindInfoBaseAddress(range);
-    }
-
-    private TargetPointer GetUnwindInfoBaseAddress(RangeSection range)
-    {
         if (!range.IsVirtualIP)
-            return range.Data!.RangeBegin;
+            return range.Data.RangeBegin;
 
-        Data.Module module = _target.ProcessedData.GetOrAdd<Data.Module>(range.Data!.R2RModule);
+        Data.Module module = _target.ProcessedData.GetOrAdd<Data.Module>(range.Data.R2RModule);
         Data.ReadyToRunInfo r2rInfo = _target.ProcessedData.GetOrAdd<Data.ReadyToRunInfo>(module.ReadyToRunInfo);
         return r2rInfo.LoadedImageBase;
     }

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/ExecutionManager/ExecutionManager_1.cs

@@ -25,7 +25,6 @@ internal ExecutionManager_1(Target target)
     public TargetCodePointer GetDiagnosticCodeStartFromEntryPoint(TargetCodePointer entryPoint) => _executionManagerCore.GetDiagnosticCodeStartFromEntryPoint(entryPoint);
     public bool IsFunclet(CodeBlockHandle codeInfoHandle) => _executionManagerCore.IsFunclet(codeInfoHandle);
     public bool IsFilterFunclet(CodeBlockHandle codeInfoHandle) => _executionManagerCore.IsFilterFunclet(codeInfoHandle);
-    public bool TryGetUnwindInfo(TargetCodePointer controlPC, out TargetPointer runtimeFunction, out TargetPointer unwindInfoBaseAddress) => _executionManagerCore.TryGetUnwindInfo(controlPC, out runtimeFunction, out unwindInfoBaseAddress);
     public TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle) => _executionManagerCore.GetUnwindInfo(codeInfoHandle);
     public TargetPointer GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle) => _executionManagerCore.GetUnwindInfoBaseAddress(codeInfoHandle);
     public TargetPointer GetDebugInfo(CodeBlockHandle codeInfoHandle, out bool hasFlagByte) => _executionManagerCore.GetDebugInfo(codeInfoHandle, out hasFlagByte);

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/StackWalk/Context/Wasm/WasmR2RInfo.cs

@@ -49,14 +49,14 @@ public bool TryGetVirtualIPBase(uint frameIdentity, out ulong baseVirtualIP)
     public bool TryGetUnwindData(TargetCodePointer controlPC, out TargetPointer unwindDataAddress)
     {
         unwindDataAddress = TargetPointer.Null;
-        if (!_executionManager.TryGetUnwindInfo(
-            controlPC,
-            out TargetPointer runtimeFunctionAddress,
-            out TargetPointer unwindInfoBaseAddress))
-        {
+        if (_executionManager.GetCodeBlockHandle(controlPC) is not CodeBlockHandle codeBlock)
+            return false;
+
+        TargetPointer runtimeFunctionAddress = _executionManager.GetUnwindInfo(codeBlock);
+        if (runtimeFunctionAddress == TargetPointer.Null)
             return false;
-        }
 
+        TargetPointer unwindInfoBaseAddress = _executionManager.GetUnwindInfoBaseAddress(codeBlock);
         RuntimeFunction runtimeFunction = _target.ProcessedData.GetOrAdd<RuntimeFunction>(runtimeFunctionAddress);
         unwindDataAddress = unwindInfoBaseAddress + runtimeFunction.UnwindData;
         return true;

src/native/managed/cdac/tests/UnitTests/ExecutionManager/ExecutionManagerTests.cs

@@ -493,18 +493,6 @@ public void GetMethodDesc_R2R_WasmVirtualIPRangeList_ResolvesCapturedShape()
         Assert.Equal(new TargetPointer(CapturedVirtualIP), em.GetStartAddress(handle.Value));
         Assert.Equal(new TargetPointer(LoadedImageBase), em.GetUnwindInfoBaseAddress(handle.Value));
         Assert.Equal(new TargetPointer(runtimeFunctionsAddress + (ulong)runtimeFunctionSize), em.GetUnwindInfo(handle.Value));
-        Assert.True(em.TryGetUnwindInfo(
-            virtualIP,
-            out TargetPointer runtimeFunction,
-            out TargetPointer unwindInfoBaseAddress));
-        Assert.Equal(new TargetPointer(runtimeFunctionsAddress + (ulong)runtimeFunctionSize), runtimeFunction);
-        Assert.Equal(new TargetPointer(LoadedImageBase), unwindInfoBaseAddress);
-        Assert.False(em.TryGetUnwindInfo(
-            new TargetCodePointer(0x7000_0000),
-            out runtimeFunction,
-            out unwindInfoBaseAddress));
-        Assert.Equal(TargetPointer.Null, runtimeFunction);
-        Assert.Equal(TargetPointer.Null, unwindInfoBaseAddress);
         Assert.Equal(new TargetPointer(moduleAddress), em.FindReadyToRunModule(new TargetPointer(CapturedVirtualIP)));
         Assert.Equal(CodeKind.ReadyToRun, em.GetCodeKind(virtualIP));
     }

src/native/managed/cdac/tests/UnitTests/StackWalkTests.cs

@@ -1570,21 +1570,13 @@ public InterpreterExecutionManager(
         public CodeKind GetCodeKind(TargetCodePointer codeAddress)
             => _interpreterIps.Contains(codeAddress.Value) ? CodeKind.Interpreter : default;
 
-        public bool TryGetUnwindInfo(
-            TargetCodePointer controlPC,
-            out TargetPointer runtimeFunction,
-            out TargetPointer unwindInfoBaseAddress)
-        {
-            if ((_managedIps?.Contains(controlPC.Value) ?? false) && _unwindInfo is not null)
-            {
-                (runtimeFunction, unwindInfoBaseAddress) = _unwindInfo();
-                return runtimeFunction != TargetPointer.Null;
-            }
+        public TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle)
+            => (_managedIps?.Contains(codeInfoHandle.Address.Value) ?? false) && _unwindInfo is not null
+                ? _unwindInfo().RuntimeFunction
+                : TargetPointer.Null;
 
-            runtimeFunction = TargetPointer.Null;
-            unwindInfoBaseAddress = TargetPointer.Null;
-            return false;
-        }
+        public TargetPointer GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle)
+            => _unwindInfo?.Invoke().BaseAddress ?? TargetPointer.Null;
     }
 
     private static IExecutionManager CreateInterpreterExecutionManager(

src/native/managed/cdac/tests/UnitTests/WasmR2RInfoTests.cs

@@ -36,22 +36,12 @@ private sealed class FakeExecutionManager : IExecutionManager
         public TargetPointer RuntimeFunction { get; set; }
         public TargetPointer UnwindInfoBaseAddress { get; set; }
 
-        public bool TryGetUnwindInfo(
-            TargetCodePointer controlPC,
-            out TargetPointer runtimeFunction,
-            out TargetPointer unwindInfoBaseAddress)
-        {
-            if (controlPC == ControlPC && RuntimeFunction != TargetPointer.Null)
-            {
-                runtimeFunction = RuntimeFunction;
-                unwindInfoBaseAddress = UnwindInfoBaseAddress;
-                return true;
-            }
-
-            runtimeFunction = TargetPointer.Null;
-            unwindInfoBaseAddress = TargetPointer.Null;
-            return false;
-        }
+        public CodeBlockHandle? GetCodeBlockHandle(TargetCodePointer ip)
+            => ip == ControlPC ? new CodeBlockHandle(ip.AsTargetPointer) : null;
+
+        public TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle) => RuntimeFunction;
+
+        public TargetPointer GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle) => UnwindInfoBaseAddress;
     }
 
     // Builds a target whose FunctionTableIndexRangeList global points at a *slot* (pointer-to-pointer),
@@ -183,6 +173,35 @@ public void TryGetUnwindData_ReturnsImageBasePlusUnwindData()
         Assert.Equal(LoadedImageBase + FunctionUnwindData, unwindData.Value);
     }
 
+    [Theory]
+    [InlineData(0x102u, 0x40u)]
+    [InlineData(0x122u, 0x80u)]
+    public void TryGetUnwindData_ExecutionManager_ResolvesRootAndFunclet(uint offset, uint expectedUnwindData)
+    {
+        const ulong MethodDescAddress = 0x0101_aaa0;
+        const ulong JitManagerAddress = 0x000b_ff00;
+        MockExecutionManagerBuilder emBuilder = new(
+            "c1", WasmArch, MockExecutionManagerBuilder.DefaultAllocationRange, isWasm: true);
+        var virtualIPRange = emBuilder.AllocateJittedCodeRange(SyntheticMinVirtualIP, 0x400);
+        MockReadyToRunInfo r2rInfo = emBuilder.AddReadyToRunInfo([0x100, 0x8000_0120, 0x180], []);
+        r2rInfo.MinVirtualIP = SyntheticMinVirtualIP;
+        r2rInfo.LoadedImageBase = LoadedImageBase;
+        emBuilder.SetRuntimeFunctionUnwindData(r2rInfo, 0, 0x40);
+        emBuilder.SetRuntimeFunctionUnwindData(r2rInfo, 1, 0x80);
+        new MockHashMapBuilder(emBuilder.Builder).PopulatePtrMap(
+            r2rInfo.EntryPointToMethodDescMapAddress,
+            [(SyntheticMinVirtualIP + FunctionBeginAddress, MethodDescAddress)]);
+        MockLoaderModule module = emBuilder.AddReadyToRunModule(r2rInfo.Address);
+        emBuilder.AddVirtualIPRangeSection(virtualIPRange, JitManagerAddress, module.Address);
+        Target target = ExecutionManager.ExecutionManagerTests.CreateTarget(
+            emBuilder, targetArchitecture: RuntimeInfoArchitecture.Wasm);
+        WasmR2RInfo info = new(target);
+
+        Assert.True(info.TryGetUnwindData(
+            new TargetCodePointer(SyntheticMinVirtualIP + offset), out TargetPointer unwindData));
+        Assert.Equal(new TargetPointer(LoadedImageBase + expectedUnwindData), unwindData);
+    }
+
     [Fact]
     public void TryGetVirtualIPBase_IndexNotInAnySection_ReturnsFalse()
     {

src/native/managed/cdac/tests/UnitTests/WasmUnwinderTests.cs

@@ -49,24 +49,14 @@ private sealed class FakeExecutionManager : IExecutionManager
     {
         public Dictionary<ulong, (TargetPointer RuntimeFunction, TargetPointer BaseAddress)> UnwindInfo { get; } = new();
 
-        public bool TryGetUnwindInfo(
-            TargetCodePointer controlPC,
-            out TargetPointer runtimeFunction,
-            out TargetPointer unwindInfoBaseAddress)
-        {
-            if (UnwindInfo.TryGetValue(
-                controlPC.Value,
-                out (TargetPointer RuntimeFunction, TargetPointer BaseAddress) info))
-            {
-                runtimeFunction = info.RuntimeFunction;
-                unwindInfoBaseAddress = info.BaseAddress;
-                return true;
-            }
+        public CodeBlockHandle? GetCodeBlockHandle(TargetCodePointer ip)
+            => UnwindInfo.ContainsKey(ip.Value) ? new CodeBlockHandle(ip.AsTargetPointer) : null;
 
-            runtimeFunction = TargetPointer.Null;
-            unwindInfoBaseAddress = TargetPointer.Null;
-            return false;
-        }
+        public TargetPointer GetUnwindInfo(CodeBlockHandle codeInfoHandle)
+            => UnwindInfo[codeInfoHandle.Address.Value].RuntimeFunction;
+
+        public TargetPointer GetUnwindInfoBaseAddress(CodeBlockHandle codeInfoHandle)
+            => UnwindInfo[codeInfoHandle.Address.Value].BaseAddress;
     }
 
     private static TestPlaceholderTarget CreateTarget(MockMemorySpace.HeapFragment[] fragments)