1 files changed, 105 insertions, 70 deletions

diff --git a/servers/rendering/shader_preprocessor.cpp b/servers/rendering/shader_preprocessor.cpp
index d118c73c4a..5d8cd503c0 100644
--- a/servers/rendering/shader_preprocessor.cpp
+++ b/servers/rendering/shader_preprocessor.cpp
@@ -349,6 +349,8 @@ void ShaderPreprocessor::process_directive(Tokenizer *p_tokenizer) {
 		process_ifdef(p_tokenizer);
 	} else if (directive == "ifndef") {
 		process_ifndef(p_tokenizer);
+	} else if (directive == "elif") {
+		process_elif(p_tokenizer);
 	} else if (directive == "else") {
 		process_else(p_tokenizer);
 	} else if (directive == "endif") {
@@ -415,10 +417,62 @@ void ShaderPreprocessor::process_define(Tokenizer *p_tokenizer) {
 	}
 }
 
+void ShaderPreprocessor::process_elif(Tokenizer *p_tokenizer) {
+	const int line = p_tokenizer->get_line();
+
+	if (state->current_branch == nullptr || state->current_branch->else_defined) {
+		set_error(RTR("Unmatched elif."), line);
+		return;
+	}
+	if (state->previous_region != nullptr) {
+		state->previous_region->to_line = line - 1;
+	}
+
+	String body = tokens_to_string(p_tokenizer->advance('\n')).strip_edges();
+	if (body.is_empty()) {
+		set_error(RTR("Missing condition."), line);
+		return;
+	}
+
+	Error error = expand_macros(body, line, body);
+	if (error != OK) {
+		return;
+	}
+
+	Expression expression;
+	Vector<String> names;
+	error = expression.parse(body, names);
+	if (error != OK) {
+		set_error(expression.get_error_text(), line);
+		return;
+	}
+
+	Variant v = expression.execute(Array(), nullptr, false);
+	if (v.get_type() == Variant::NIL) {
+		set_error(RTR("Condition evaluation error."), line);
+		return;
+	}
+
+	bool skip = false;
+	for (int i = 0; i < state->current_branch->conditions.size(); i++) {
+		if (state->current_branch->conditions[i]) {
+			skip = true;
+			break;
+		}
+	}
+
+	bool success = !skip && v.booleanize();
+	start_branch_condition(p_tokenizer, success, true);
+
+	if (state->save_regions) {
+		add_region(line + 1, success, state->previous_region->parent);
+	}
+}
+
 void ShaderPreprocessor::process_else(Tokenizer *p_tokenizer) {
 	const int line = p_tokenizer->get_line();
 
-	if (state->skip_stack_else.is_empty()) {
+	if (state->current_branch == nullptr || state->current_branch->else_defined) {
 		set_error(RTR("Unmatched else."), line);
 		return;
 	}
@@ -428,17 +482,14 @@ void ShaderPreprocessor::process_else(Tokenizer *p_tokenizer) {
 
 	p_tokenizer->advance('\n');
 
-	bool skip = state->skip_stack_else[state->skip_stack_else.size() - 1];
-	state->skip_stack_else.remove_at(state->skip_stack_else.size() - 1);
-
-	Vector<SkippedCondition *> vec = state->skipped_conditions[state->current_filename];
-	int index = vec.size() - 1;
-	if (index >= 0) {
-		SkippedCondition *cond = vec[index];
-		if (cond->end_line == -1) {
-			cond->end_line = p_tokenizer->get_line();
+	bool skip = false;
+	for (int i = 0; i < state->current_branch->conditions.size(); i++) {
+		if (state->current_branch->conditions[i]) {
+			skip = true;
+			break;
 		}
 	}
+	state->current_branch->else_defined = true;
 
 	if (state->save_regions) {
 		add_region(line + 1, !skip, state->previous_region->parent);
@@ -462,16 +513,10 @@ void ShaderPreprocessor::process_endif(Tokenizer *p_tokenizer) {
 		state->previous_region = state->previous_region->parent;
 	}
 
-	Vector<SkippedCondition *> vec = state->skipped_conditions[state->current_filename];
-	int index = vec.size() - 1;
-	if (index >= 0) {
-		SkippedCondition *cond = vec[index];
-		if (cond->end_line == -1) {
-			cond->end_line = p_tokenizer->get_line();
-		}
-	}
-
 	p_tokenizer->advance('\n');
+
+	state->current_branch = state->current_branch->parent;
+	state->branches.pop_back();
 }
 
 void ShaderPreprocessor::process_if(Tokenizer *p_tokenizer) {
@@ -703,24 +748,19 @@ void ShaderPreprocessor::add_region(int p_line, bool p_enabled, Region *p_parent
 	state->previous_region = &state->regions[region.file].push_back(region)->get();
 }
 
-void ShaderPreprocessor::start_branch_condition(Tokenizer *p_tokenizer, bool p_success) {
-	state->condition_depth++;
-
-	if (p_success) {
-		state->skip_stack_else.push_back(true);
+void ShaderPreprocessor::start_branch_condition(Tokenizer *p_tokenizer, bool p_success, bool p_continue) {
+	if (!p_continue) {
+		state->condition_depth++;
+		state->current_branch = &state->branches.push_back(Branch(p_success, state->current_branch))->get();
 	} else {
-		SkippedCondition *cond = memnew(SkippedCondition());
-		cond->start_line = p_tokenizer->get_line();
-		state->skipped_conditions[state->current_filename].push_back(cond);
-
+		state->current_branch->conditions.push_back(p_success);
+	}
+	if (!p_success) {
 		Vector<String> ends;
+		ends.push_back("elif");
 		ends.push_back("else");
 		ends.push_back("endif");
-		if (next_directive(p_tokenizer, ends) == "else") {
-			state->skip_stack_else.push_back(false);
-		} else {
-			state->skip_stack_else.push_back(true);
-		}
+		next_directive(p_tokenizer, ends);
 	}
 }
 
@@ -738,46 +778,44 @@ void ShaderPreprocessor::expand_output_macros(int p_start, int p_line_number) {
 }
 
 Error ShaderPreprocessor::expand_macros(const String &p_string, int p_line, String &r_expanded) {
-	Vector<Pair<String, Define *>> active_defines;
-	active_defines.resize(state->defines.size());
-	int index = 0;
-	for (const RBMap<String, Define *>::Element *E = state->defines.front(); E; E = E->next()) {
-		active_defines.set(index++, Pair<String, Define *>(E->key(), E->get()));
-	}
+	String iterative = p_string;
+	int pass_count = 0;
+	bool expanded = true;
 
-	return expand_macros(p_string, p_line, active_defines, r_expanded);
-}
+	while (expanded) {
+		expanded = false;
 
-Error ShaderPreprocessor::expand_macros(const String &p_string, int p_line, Vector<Pair<String, Define *>> p_defines, String &r_expanded) {
-	r_expanded = p_string;
-	// When expanding macros we must only evaluate them once.
-	// Later we continue expanding but with the already
-	// evaluated macros removed.
-	for (int i = 0; i < p_defines.size(); i++) {
-		Pair<String, Define *> define_pair = p_defines[i];
-
-		Error error = expand_macros_once(r_expanded, p_line, define_pair, r_expanded);
-		if (error != OK) {
-			return error;
+		// As long as we find something to expand, keep going.
+		for (const RBMap<String, Define *>::Element *E = state->defines.front(); E; E = E->next()) {
+			if (expand_macros_once(iterative, p_line, E, iterative)) {
+				expanded = true;
+			}
 		}
 
-		// Remove expanded macro and recursively replace remaining.
-		p_defines.remove_at(i);
-		return expand_macros(r_expanded, p_line, p_defines, r_expanded);
+		pass_count++;
+		if (pass_count > 50) {
+			set_error(RTR("Macro expansion limit exceeded."), p_line);
+			break;
+		}
 	}
 
+	r_expanded = iterative;
+
+	if (!state->error.is_empty()) {
+		return FAILED;
+	}
 	return OK;
 }
 
-Error ShaderPreprocessor::expand_macros_once(const String &p_line, int p_line_number, Pair<String, Define *> p_define_pair, String &r_expanded) {
+bool ShaderPreprocessor::expand_macros_once(const String &p_line, int p_line_number, const RBMap<String, Define *>::Element *p_define_pair, String &r_expanded) {
 	String result = p_line;
 
-	const String &key = p_define_pair.first;
-	const Define *define = p_define_pair.second;
+	const String &key = p_define_pair->key();
+	const Define *define = p_define_pair->value();
 
 	int index_start = 0;
 	int index = 0;
-	while (find_match(result, key, index, index_start)) {
+	if (find_match(result, key, index, index_start)) {
 		String body = define->body;
 		if (define->arguments.size() > 0) {
 			// Complex macro with arguments.
@@ -785,14 +823,14 @@ Error ShaderPreprocessor::expand_macros_once(const String &p_line, int p_line_nu
 			int args_end = p_line.find(")", args_start);
 			if (args_start == -1 || args_end == -1) {
 				set_error(RTR("Missing macro argument parenthesis."), p_line_number);
-				return FAILED;
+				return false;
 			}
 
 			String values = result.substr(args_start + 1, args_end - (args_start + 1));
 			Vector<String> args = values.split(",");
 			if (args.size() != define->arguments.size()) {
 				set_error(RTR("Invalid macro argument count."), p_line_number);
-				return FAILED;
+				return false;
 			}
 
 			// Insert macro arguments into the body.
@@ -814,11 +852,13 @@ Error ShaderPreprocessor::expand_macros_once(const String &p_line, int p_line_nu
 			// Manually reset index_start to where the body value of the define finishes.
 			// This ensures we don't skip another instance of this macro in the string.
 			index_start = index + body.length() + 1;
-			break;
 		}
+
+		r_expanded = result;
+		return true;
 	}
-	r_expanded = result;
-	return OK;
+
+	return false;
 }
 
 bool ShaderPreprocessor::find_match(const String &p_string, const String &p_value, int &r_index, int &r_index_start) {
@@ -909,12 +949,6 @@ void ShaderPreprocessor::clear() {
 			memdelete(E->get());
 		}
 
-		for (const RBMap<String, Vector<SkippedCondition *>>::Element *E = state->skipped_conditions.front(); E; E = E->next()) {
-			for (SkippedCondition *condition : E->get()) {
-				memdelete(condition);
-			}
-		}
-
 		memdelete(state);
 	}
 	state_owner = false;
@@ -1064,6 +1098,7 @@ Error ShaderPreprocessor::preprocess(const String &p_code, const String &p_filen
 
 void ShaderPreprocessor::get_keyword_list(List<String> *r_keywords, bool p_include_shader_keywords) {
 	r_keywords->push_back("define");
+	r_keywords->push_back("elif");
 	if (p_include_shader_keywords) {
 		r_keywords->push_back("else");
 	}