Eliminate SEH interactions between the JIT and the EE during verification.

For compatibility reasons, `BadImageFormatException`s that are thrown when resolving tokens
during verification are transformed instead into verification exceptions. This transformation
currently takes place in the JIT: the JIT wraps relevant calls to `ICorJitInfo::resolveToken` with
a `__try`/`__except` that handles any exceptions that arise due to invalid metadata. This method
cannot be relied on when consuming the JIT as a dynamic library on non-Windows platforms
due to type identity problems in the runtime's SEH emulation. Furthermore, these filters cannot
use the proposed solution to the JIT's other uses of SEH across the JIT/EE interface, since they
are more complex than a call to `ICorJitInfo::FilterException`. Instead, this change introduces a
new method, `ICorJitInfo::tryResolveToken`, which is only used during verification. This method
implements filtering that is equivalent to the current implementation, but does so in the EE rather
than in the JIT.

This is part of GitHub bugs #3058 and #4130.

[tfs-changeset: 1600443]

1 files changed, 6 insertions, 0 deletions

diff --git a/src/zap/zapinfo.cpp b/src/zap/zapinfo.cpp
index 345a920902..4d2d7f8636 100644
--- a/src/zap/zapinfo.cpp
+++ b/src/zap/zapinfo.cpp
@@ -3455,6 +3455,12 @@ void ZapInfo::resolveToken(CORINFO_RESOLVED_TOKEN * pResolvedToken)
 }
 
 //-----------------------------------------------------------------------------
+bool ZapInfo::tryResolveToken(CORINFO_RESOLVED_TOKEN * pResolvedToken)
+{
+    return m_pEEJitInfo->tryResolveToken(pResolvedToken);
+}
+
+//-----------------------------------------------------------------------------
 void ZapInfo::findSig(CORINFO_MODULE_HANDLE tokenScope,
                       unsigned sigTOK,
                       CORINFO_CONTEXT_HANDLE tokenContext,