Implement basic support for managed exception handling.

Implementation of the managed exception handling in this change is by far not yet complete but it is a good starting point that we can build on top of it. Basically this code allows managed exceptions to be thrown and caught. The finally blocks and nested try/catch works too. But re-throwing an exception from a catch block and many other corner cases do not work yet.

In addition, RtlRestoreContext needs to be properly implemented. This change introduces a very simply implementation that works only in those cases where XMM registers are not used in the code that handles the exception so they don’t need to be restored. I have created a separate issue to track it (https://github.com/dotnet/coreclr/issues/360).

This change also fixes an issue in JIT where JIT was incorrectly passing arguments in the RCX and RDX registers to the finally and catch funclets.

1 files changed, 5 insertions, 4 deletions

diff --git a/src/vm/stackwalk.cpp b/src/vm/stackwalk.cpp
index e677cef7e9..627765a996 100644
--- a/src/vm/stackwalk.cpp
+++ b/src/vm/stackwalk.cpp
@@ -606,10 +606,11 @@ PCODE Thread::VirtualUnwindCallFrame(T_CONTEXT* pContext,
                                             ARM_ONLY((DWORD*))(&uImageBase),
                                             NULL);
 #else // !FEATURE_PAL
-        // For PAL, this method should never be called without valid pCodeInfo, since there is no
-        // other way to get the function entry.
-        pFunctionEntry = NULL;
-        UNREACHABLE_MSG("VirtualUnwindCallFrame called with NULL pCodeInfo");
+        EECodeInfo codeInfo;
+
+        codeInfo.Init(uControlPc);
+        pFunctionEntry = codeInfo.GetFunctionEntry();
+        uImageBase = (UINT_PTR)codeInfo.GetModuleBase();
 #endif // !FEATURE_PAL
     }
     else