From d56bdbf84f8c32b5b9726208da7a98286da1e293 Mon Sep 17 00:00:00 2001
From: Graeme Geldenhuys <graemeg@gmail.com>
Date: Thu, 18 Jun 2026 18:43:23 +0100
Subject: [PATCH] feat(backend): default to the native backend; QBE is now
 opt-in
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Flip the compiler's default --backend from qbe to native.  Native has full
feature parity with QBE (the v0.11.0 cycle's 116 fixes plus the dual-backend
e2e harness brought them level), self-hosts, and gives no external codegen
dependency, source-level debugging, and a path to cross-compilation — so it
is the right default to exercise everywhere.

QBE stays fully supported via --backend qbe and remains the cold-bootstrap
root: --emit-ir still routes to QBE regardless of the default (PickTopDriver
ignores --backend for emit modes), so scripts/rolling-bootstrap.sh,
fixpoint.sh, and CI — all of which pass --emit-ir explicitly — are unaffected
by this change.  The only behaviour change is that a plain
'blaise --source X --output Y' (and a plain 'make' in runtime/) now uses the
native backend.

Flipping the default surfaced and fixed a real native gap first (the
unit-to-.o duplicate-system-defs link collision, previous commit); the full
suite is green with the TestRunner built by BOTH a QBE-built and a
native-built compiler, and all three fixpoints pass.
---
 compiler/src/main/pascal/Blaise.pas | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/compiler/src/main/pascal/Blaise.pas b/compiler/src/main/pascal/Blaise.pas
index f6cb67f..6f62e41 100644
--- a/compiler/src/main/pascal/Blaise.pas
+++ b/compiler/src/main/pascal/Blaise.pas
@@ -44,7 +44,7 @@ const
   CompilerName = 'Blaise';
 
 { Build the --backend usage fragment from the registered drivers, with
-  the default (bkQBE) entry marked.  Keeps the flag parser and the usage
+  the default (bkNative) entry marked.  Keeps the flag parser and the usage
   text from drifting out of sync with the registry when a backend is
   added. }
 function BackendUsageLine: string;
@@ -61,7 +61,7 @@ begin
       if I > 0 then
         Result := Result + ' | ';
       Result := Result + Names.Strings[I];
-      if ParseBackendName(Names.Strings[I], K) and (K = bkQBE) then
+      if ParseBackendName(Names.Strings[I], K) and (K = bkNative) then
         Result := Result + ' (default)';
     end;
   finally
@@ -150,7 +150,7 @@ begin
   AFront.EmitIR         := False;
   AFront.EmitAsm        := False;
   AFront.DumpAST        := False;
-  AFront.Backend        := bkQBE;
+  AFront.Backend        := bkNative;   { native is the default backend; QBE is opt-in via --backend qbe }
   AFront.BackendExplicit := False;
   AFront.SkipDepCodegen := False;
   AFront.EmitIfaceDir   := '';