[PDB] Support PDB-backed expressions evaluation

Summary:
This patch contains several small fixes, which makes it possible to evaluate
expressions on Windows using information from PDB. The changes are:
- several sanitize checks;
- make IRExecutionUnit::MemoryManager::getSymbolAddress to not return a magic
  value on a failure, because callers wait 0 in this case;
- entry point required to be a file address, not RVA, in the ObjectFilePECOFF;
- do not crash on a debuggee second chance exception - it may be an expression
  evaluation crash;
- create parameter declarations for functions in AST to make it possible to call
  debugee functions from expressions;
- relax name searching rules for variables, functions, namespaces and types. Now
  it works just like in the DWARF plugin;
- fix endless recursion in SymbolFilePDB::ParseCompileUnitFunctionForPDBFunc.

Reviewers: zturner, asmith, stella.stamenova

Reviewed By: stella.stamenova, asmith

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D53759

llvm-svn: 347962

2 files changed, 4 insertions, 3 deletions

diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
index b6ba70289d9..a121f8d3afd 100644
--- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp
@@ -957,8 +957,9 @@ ProcessWindows::OnDebugException(bool first_chance,
   }
 
   if (!first_chance) {
-    // Any second chance exception is an application crash by definition.
-    SetPrivateState(eStateCrashed);
+    // Not any second chance exception is an application crash by definition.
+    // It may be an expression evaluation crash.
+    SetPrivateState(eStateStopped);
   }
 
   ExceptionResult result = ExceptionResult::SendToApplication;
diff --git a/lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp
index b3f507128f8..cd4f3f64b9b 100644
--- a/lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp
+++ b/lldb/source/Plugins/Process/Windows/Common/RegisterContextWindows.cpp
@@ -42,7 +42,7 @@ bool RegisterContextWindows::ReadAllRegisterValues(
     lldb::DataBufferSP &data_sp) {
   if (!CacheAllRegisterValues())
     return false;
-  if (data_sp->GetByteSize() < sizeof(m_context)) {
+  if (!data_sp || data_sp->GetByteSize() < sizeof(m_context)) {
     data_sp.reset(new DataBufferHeap(sizeof(CONTEXT), 0));
   }
   memcpy(data_sp->GetBytes(), &m_context, sizeof(m_context));