[lldb[RPC] Upstream RPC server interface emitters

This commit upstreams the LLDB RPC server interface emitters. These
emitters generate the server-side API interfaces for RPC, which
communicate directly with liblldb itself out of process using the SB
API.

https://discourse.llvm.org/t/rfc-upstreaming-lldb-rpc/85804

Author: chelcassanova

lldb/test/Shell/RPC/Generator/Inputs/Server/CheckBasicIncludesEmit.h

@@ -0,0 +1,6 @@
+// This ia a basic header file used to check that the server-side emitter
+// for rpc-gen emits an expected set of includes in a generated source file.
+#ifndef LLDB_API_SBRPC_CHECKBASICINCLUDE_H
+#define LLDB_API_SBRPC_CHECKBASICINCLUDE_H
+
+#endif // LLDB_API_SBRPC_CHECKBASICINCLUDE_H

lldb/test/Shell/RPC/Generator/Inputs/Server/CheckConstCharPointer.h

@@ -0,0 +1,14 @@
+#ifndef LLDB_API_SBRPC_CHECKCONSTCHARPOINTER_H
+#define LLDB_API_SBRPC_CHECKCONSTCHARPOINTER_H
+
+namespace lldb {
+class LLDB_API SBRPC_CHECKCONSTCHARPOINTER {
+public:
+  // const char * parameters must decoded as rpc_common::ConstCharPointer in server side
+  // source files.
+  int CheckConstCharPointer(char *string);
+
+}; // class SBRPC_CHECKCONSTCHARPOINTER
+} // namespace lldb
+
+#endif // LLDB_API_SBRPC_CHECKCONSTCHARPOINTER_H

lldb/test/Shell/RPC/Generator/Tests/Server/CheckBasicIncludesEmit.test

@@ -0,0 +1,15 @@
+# Disabling until the lldb-rpc-gen tool lands.
+XFAIL: *
+RUN: mkdir -p %t/server
+RUN: mkdir -p %t/lib
+RUN: %lldb-rpc-gen --output-dir=%t %S/../../Inputs/CheckBasicIncludesEmit.h
+
+RUN: cat %t/lib/CheckBasicIncludesEmit.cpp | FileCheck %s
+
+# All server-side source files must have these includes at the top of their files.
+CHECK: #include "RPCUserServer.h"
+CHECK: #include "SBAPI.h"
+CHECK: #include <lldb-rpc/common/RPCArgument.h>
+CHECK: #include <lldb-rpc/common/RPCCommon.h>
+CHECK: #include <lldb-rpc/common/RPCFunction.h>
+CHECK: #include <lldb/API/LLDB.h>

lldb/test/Shell/RPC/Generator/Tests/Server/CheckConstCharPointer.test

@@ -0,0 +1,11 @@
+# Disabling until the lldb-rpc-gen tool lands.
+XFAIL: *
+RUN: mkdir -p %t/server
+RUN: mkdir -p %t/lib
+RUN: %lldb-rpc-gen --output-dir=%t %S/../../Inputs/CheckConstCharPointer.h
+
+RUN: cat %t/lib/CheckConstCharPointer.cpp | FileCheck %s
+
+# const char * pointers must be decoded as rpc_common::ConstCharPointer objects
+# in server side source files.
+CHECK: rpc_common::ConstCharPointer string