dwarf_extractor.cpp: Enable limited support for C++ (#3540)

While band-aid fixes like this is not plausible IMO,
some people prefer to have some debug info even if it's
partial/limited/broken. This commit partially (re)enables
C++ processing. On the other hand, do not bother to process
variables because it's known incompatible with C++.

core/iwasm/compilation/debug/dwarf_extractor.cpp

@@ -305,6 +305,7 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
      * https://github.com/bytecodealliance/wasm-micro-runtime/issues/3163
      */
     LanguageType language_type = function.GetLanguage();
+    bool cplusplus = false;
     switch (language_type) {
         case eLanguageTypeC89:
         case eLanguageTypeC:
@@ -312,6 +313,14 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
         case eLanguageTypeC11:
         case eLanguageTypeC17:
             break;
+        case eLanguageTypeC_plus_plus:
+        case eLanguageTypeC_plus_plus_03:
+        case eLanguageTypeC_plus_plus_11:
+        case eLanguageTypeC_plus_plus_14:
+        case eLanguageTypeC_plus_plus_17:
+        case eLanguageTypeC_plus_plus_20:
+            cplusplus = true;
+            break;
         default:
             LOG_WARNING("func %s has unsupported language_type 0x%x",
                         function_name, (int)language_type);
@@ -325,11 +334,14 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
     LLVMMetadataRef File = comp_ctx->debug_file; /* a fallback */
 
     LLVMMetadataRef ParamTypes[num_function_args + 1];
+    size_t num_param_types = 0;
 
+    if (!cplusplus) {
+        num_param_types = num_function_args + 1;
         ParamTypes[0] = lldb_type_to_type_dbi(comp_ctx, return_type);
 
-    for (uint32_t function_arg_idx = 0; function_arg_idx < num_function_args;
+        for (uint32_t function_arg_idx = 0;
-         ++function_arg_idx) {
+             function_arg_idx < num_function_args; ++function_arg_idx) {
             SBType function_arg_type =
                 function_args.GetTypeAtIndex(function_arg_idx);
 
@@ -349,6 +361,7 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
                 ParamTypes[function_arg_idx + 1] = NULL;
             }
         }
+    }
 
     auto compile_unit = sc.GetCompileUnit();
     auto file_spec = compile_unit.GetFileSpec();
@@ -366,7 +379,7 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
     }
 
     LLVMMetadataRef FunctionTy = LLVMDIBuilderCreateSubroutineType(
-        DIB, File, ParamTypes, num_function_args + 1, LLVMDIFlagZero);
+        DIB, File, ParamTypes, num_param_types, LLVMDIFlagZero);
 
     auto line_entry = sc.GetLineEntry();
     LLVMMetadataRef ReplaceableFunctionMetadata =
@@ -386,13 +399,6 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
 
     LLVMMetadataRef ParamExpression =
         LLVMDIBuilderCreateExpression(DIB, NULL, 0);
-    auto variable_list =
-        function.GetBlock().GetVariables(extractor->target, true, false, false);
-    if (num_function_args != variable_list.GetSize()) {
-        LOG_ERROR(
-            "function args number mismatch!:value number=%d, function args=%d",
-            variable_list.GetSize(), num_function_args);
-    }
 
     LLVMMetadataRef ParamLocation = LLVMDIBuilderCreateDebugLocation(
         comp_ctx->context, line_entry.GetLine(), 0, FunctionMetadata, NULL);
@@ -412,19 +418,29 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
     LLVMDIBuilderInsertDbgValueAtEnd(DIB, Param, ParamVar, ParamExpression,
                                      ParamLocation, block_curr);
 
+    if (!cplusplus) {
+        auto variable_list = function.GetBlock().GetVariables(
+            extractor->target, true, false, false);
+        if (num_function_args != variable_list.GetSize()) {
+            LOG_ERROR("function args number mismatch!:value number=%d, "
+                      "function args=%d",
+                      variable_list.GetSize(), num_function_args);
+        }
         for (uint32_t function_arg_idx = 0;
              function_arg_idx < variable_list.GetSize(); ++function_arg_idx) {
             SBValue variable(variable_list.GetValueAtIndex(function_arg_idx));
-        if (variable.IsValid() && ParamTypes[function_arg_idx + 1] != NULL) {
+            if (variable.IsValid()
+                && ParamTypes[function_arg_idx + 1] != NULL) {
                 SBDeclaration dec(variable.GetDeclaration());
                 auto valtype = variable.GetType();
-            LLVMMetadataRef ParamLocation = LLVMDIBuilderCreateDebugLocation(
+                LLVMMetadataRef ParamLocation =
+                    LLVMDIBuilderCreateDebugLocation(
                         comp_ctx->context, dec.GetLine(), dec.GetColumn(),
                         FunctionMetadata, NULL);
                 const char *varname = variable.GetName();
                 LLVMMetadataRef ParamVar = LLVMDIBuilderCreateParameterVariable(
-                DIB, FunctionMetadata, varname, varname ? strlen(varname) : 0,
+                    DIB, FunctionMetadata, varname,
-                function_arg_idx + 1 + 1,
+                    varname ? strlen(varname) : 0, function_arg_idx + 1 + 1,
                     File, // starts form 1, and 1 is exenv,
                     dec.GetLine(), ParamTypes[function_arg_idx + 1], true,
                     LLVMDIFlagZero);
@@ -435,6 +451,7 @@ lldb_function_to_function_dbi(const AOTCompContext *comp_ctx,
                                                  block_curr);
             }
         }
+    }
 
     return FunctionMetadata;
 }