frontend: add -fincremental, -fno-incremental flag

Remove --debug-incremental

This flag is also added to the build system. Importantly, this tells
Compile step whether or not to keep the compiler running between
rebuilds. It defaults off because it is currently crashing
zirUpdateRefs.

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/std/Build/Step/Compile.zig b/lib/std/Build/Step/Compile.zig
index 9af6ace9c0..724656ce29 100644
--- a/lib/std/Build/Step/Compile.zig
+++ b/lib/std/Build/Step/Compile.zig
@@ -1679,6 +1679,8 @@ fn getZigArgs(compile: *Compile) ![][]const u8 {
         b.fmt("{}", .{err_limit}),
     });
 
+    try addFlag(&zig_args, "incremental", b.graph.incremental);
+
     try zig_args.append("--listen=-");
 
     // Windows has an argument length limit of 32,766 characters, macOS 262,144 and Linux
@@ -1750,7 +1752,7 @@ fn make(step: *Step, options: Step.MakeOptions) !void {
     const maybe_output_bin_path = step.evalZigProcess(
         zig_args,
         options.progress_node,
-        options.watch,
+        (b.graph.incremental == true) and options.watch,
     ) catch |err| switch (err) {
         error.NeedCompileErrorCheck => {
             assert(compile.expect_errors != null);