to execute expressions even in the absence of a process.
This allows expressions to run in situations where the
target cannot run -- e.g., to perform calculations based
on type information, or to inspect a binary's static
data.

This modification touches the following files:

lldb-private-enumerations.h
  Introduce a new enum specifying the policy for
  processing an expression.  Some expressions should
  always be JITted, for example if they are functions
  that will be used over and over again.  Some
  expressions should always be interpreted, for
  example if the target is unsafe to run.  For most,
  it is acceptable to JIT them, but interpretation
  is preferable when possible.

Target.[h,cpp]
  Have EvaluateExpression now accept the new enum.

ClangExpressionDeclMap.[cpp,h]
  Add support for the IR interpreter and also make
  the ClangExpressionDeclMap more robust in the 
  absence of a process.

ClangFunction.[cpp,h]
  Add support for the new enum.

IRInterpreter.[cpp,h]
  New implementation.

ClangUserExpression.[cpp,h]
  Add support for the new enum, and for running 
  expressions in the absence of a process.

ClangExpression.h
  Remove references to the old DWARF-based method
  of evaluating expressions, because it has been
  superseded for now.

ClangUtilityFunction.[cpp,h]
  Add support for the new enum.

ClangExpressionParser.[cpp,h]
  Add support for the new enum, remove references
  to DWARF, and add support for checking whether
  the expression could be evaluated statically.

IRForTarget.[h,cpp]
  Add support for the new enum, and add utility
  functions to support the interpreter.

IRToDWARF.cpp
  Removed

CommandObjectExpression.cpp
  Remove references to the obsolete -i option.

Process.cpp 
  Modify calls to ClangUserExpression::Evaluate
  to pass the correct enum (for dlopen/dlclose)

SBValue.cpp
  Add support for the new enum.

SBFrame.cpp
  Add support for he new enum.

BreakpointOptions.cpp
  Add support for the new enum.

llvm-svn: 139772