cc: Add vast-debug option.

Author: xlauko

include/vast/Frontend/Options.hpp

@@ -70,9 +70,10 @@ namespace vast::cc
         constexpr string_ref emit_llvm = "emit-llvm";
         constexpr string_ref emit_obj  = "emit-obj";
         constexpr string_ref emit_asm  = "emit-asm";
-
         constexpr string_ref emit_mlir = "emit-mlir";
 
+        constexpr string_ref debug = "debug";
+
         constexpr string_ref simplify = "simplify";
 
         constexpr string_ref show_locs = "show-locs";

lib/vast/Frontend/Consumer.cpp

@@ -200,7 +200,12 @@ namespace vast::cc {
         bool verify_diagnostics = vargs.has_option(opt::vast_verify_diags);
 
         mlir::SourceMgrDiagnosticVerifierHandler src_mgr_handler(mlir_src_mgr, mctx);
-        mctx->printOpOnDiagnostic(false);
+
+        if (vargs.has_option(opt::debug)) {
+            mctx->printOpOnDiagnostic(true);
+            mctx->printStackTraceOnDiagnostic(true);
+            llvm::DebugFlag = true;
+        }
 
         execute_pipeline(mod.get(), mctx);