From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Thu, 4 Feb 2021 14:53:55 +0000 (+0100)
Subject: vala: Add Block.unreachable_exit and have it set accordingly by FlowAnalyzer
X-Git-Tag: 0.51.1~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1bf1e999fcfd32dacbc7396dbeda64882272b8a;p=thirdparty%2Fvala.git

vala: Add Block.unreachable_exit and have it set accordingly by FlowAnalyzer

Use this control flow information in codegen rather than doing an
educated guess based on occurring ReturnStatement nodes.

See https://gitlab.gnome.org/GNOME/vala/issues/838
---

diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 9e46dd2f6..a5c42b01c 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -2404,17 +2404,13 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
 			cfile.add_function (unref_fun);
 		}
 
-		bool reachable_exit_block = true;
 		foreach (Statement stmt in b.get_statements ()) {
-			if (stmt is ReturnStatement) {
-				reachable_exit_block = false;
-			}
 			push_line (stmt.source_reference);
 			stmt.emit (this);
 			pop_line ();
 		}
 
-		if (reachable_exit_block) {
+		if (!b.unreachable_exit) {
 			if (b.parent_symbol is Method) {
 				unowned Method m = (Method) b.parent_symbol;
 				// check postconditions
diff --git a/vala/valablock.vala b/vala/valablock.vala
index e13f2b2be..e002909bf 100644
--- a/vala/valablock.vala
+++ b/vala/valablock.vala
@@ -32,6 +32,11 @@ public class Vala.Block : Symbol, Statement {
 	 */
 	public bool contains_jump_statement { get; set; }
 
+	/**
+	 * Specifies whether the end of this block is unreachable.
+	 */
+	public bool unreachable_exit { get; set; }
+
 	public bool captured { get; set; }
 
 	private List<Statement> statement_list = new ArrayList<Statement> ();
diff --git a/vala/valaflowanalyzer.vala b/vala/valaflowanalyzer.vala
index a86bda42a..a5a8be993 100644
--- a/vala/valaflowanalyzer.vala
+++ b/vala/valaflowanalyzer.vala
@@ -235,6 +235,8 @@ public class Vala.FlowAnalyzer : CodeVisitor {
 			}
 
 			current_block.connect (m.return_block);
+		} else {
+			m.body.unreachable_exit = true;
 		}
 
 		analyze_body (m.entry_block);