From a4a4220524eab09288445eabf645944ade04eb80 Mon Sep 17 00:00:00 2001
From: Andrew Au <andrewau@microsoft.com>
Date: Wed, 27 Jun 2018 11:15:04 -0700
Subject: [PATCH] Get/Set the ThreadContext natively if the debuggee is block
 on garbage collection events

Commit migrated from https://github.com/dotnet/coreclr/commit/59acd546c2d326e8a4ec11f078a1f0edde4dabaa
---
 src/coreclr/src/debug/di/process.cpp | 29 ++++++++++++++++++++++++-----
 src/coreclr/src/debug/di/rspriv.h    |  4 +++-
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/coreclr/src/debug/di/process.cpp b/src/coreclr/src/debug/di/process.cpp
index 64446cd..718fff2 100644
--- a/src/coreclr/src/debug/di/process.cpp
+++ b/src/coreclr/src/debug/di/process.cpp
@@ -984,7 +984,8 @@ CordbProcess::CordbProcess(ULONG64 clrInstanceId,
     m_pEventChannel(NULL),
     m_fAssertOnTargetInconsistency(false),
     m_runtimeOffsetsInitialized(false),
-    m_writableMetadataUpdateMode(LegacyCompatPolicy)
+    m_writableMetadataUpdateMode(LegacyCompatPolicy),
+    m_isBlockedOnGarbageCollectionEvent(false)
 {
     _ASSERTE((m_id == 0) == (pShim == NULL));
 
@@ -3644,6 +3645,8 @@ HRESULT CordbProcess::Continue(BOOL fIsOutOfBand)
 {
     PUBLIC_API_ENTRY(this);
 
+    this->m_isBlockedOnGarbageCollectionEvent = false;
+
     if (m_pShim == NULL) // This API is moved off to the shim
     {
         // bias towards failing with CORDBG_E_NUETERED.
@@ -4911,6 +4914,7 @@ void CordbProcess::RawDispatchEvent(
     case DB_IPCE_BEFORE_GARBAGE_COLLECTION:
         {
             {
+                this->m_isBlockedOnGarbageCollectionEvent = true;
                 PUBLIC_CALLBACK_IN_THIS_SCOPE(this, pLockHolder, pEvent);
                 pCallback4->BeforeGarbageCollection(static_cast<ICorDebugProcess*>(this));
             }
@@ -4920,6 +4924,7 @@ void CordbProcess::RawDispatchEvent(
     case DB_IPCE_AFTER_GARBAGE_COLLECTION:
         {
             {
+                this->m_isBlockedOnGarbageCollectionEvent = true;
                 PUBLIC_CALLBACK_IN_THIS_SCOPE(this, pLockHolder, pEvent);
                 pCallback4->AfterGarbageCollection(static_cast<ICorDebugProcess*>(this));
             }
@@ -6501,9 +6506,16 @@ HRESULT CordbProcess::GetThreadContext(DWORD threadID, ULONG32 contextSize, BYTE
             }
             else
             {
-                DT_CONTEXT* managedContext;
-                hr = thread->GetManagedContext(&managedContext);
-                *pContext = *managedContext;
+                if (this->m_isBlockedOnGarbageCollectionEvent)
+                {
+                    hr = this->GetDataTarget()->GetThreadContext(threadID, CONTEXT_FULL, contextSize, context);
+                }
+                else
+                {
+                    DT_CONTEXT* managedContext;
+                    hr = thread->GetManagedContext(&managedContext);
+                    *pContext = *managedContext;
+                }
             }
         }
         EX_CATCH
@@ -6591,7 +6603,14 @@ HRESULT CordbProcess::SetThreadContext(DWORD threadID, ULONG32 contextSize, BYTE
                 hr = E_INVALIDARG;
             }
 
-            hr = thread->SetManagedContext(pContext);
+            if (this->m_isBlockedOnGarbageCollectionEvent)
+            {
+                hr = this->m_pMutableDataTarget->SetThreadContext(threadID, contextSize, context);
+            }
+            else
+            {
+                hr = thread->SetManagedContext(pContext);
+            }
         }
         EX_CATCH
         {
diff --git a/src/coreclr/src/debug/di/rspriv.h b/src/coreclr/src/debug/di/rspriv.h
index a9f5893..d3de665 100644
--- a/src/coreclr/src/debug/di/rspriv.h
+++ b/src/coreclr/src/debug/di/rspriv.h
@@ -3749,7 +3749,6 @@ public:
     // This is also used in fake-native debugging scenarios.
     bool                  m_loaderBPReceived;
 
-
 private:
 
     // MetaData dispenser. 
@@ -4114,6 +4113,9 @@ private:
 
     // controls how metadata updated in the target is handled
     WriteableMetadataUpdateMode m_writableMetadataUpdateMode;
+
+    // TODO: Comments
+    bool                  m_isBlockedOnGarbageCollectionEvent;
 };
 
 // Some IMDArocess APIs are supported as interop-only.
-- 
2.7.4