add @trap builtin

This introduces a new builtin function that compiles down to something that results in an illegal instruction exception/interrupt.
It can be used to exit a program abnormally.

This implements the builtin for all backends.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/arch/wasm/CodeGen.zig b/src/arch/wasm/CodeGen.zig
index 2f191fd834..d388bc8fab 100644
--- a/src/arch/wasm/CodeGen.zig
+++ b/src/arch/wasm/CodeGen.zig
@@ -1829,6 +1829,7 @@ fn genInst(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
         .arg => func.airArg(inst),
         .bitcast => func.airBitcast(inst),
         .block => func.airBlock(inst),
+        .trap => func.airTrap(inst),
         .breakpoint => func.airBreakpoint(inst),
         .br => func.airBr(inst),
         .bool_to_int => func.airBoolToInt(inst),
@@ -3289,6 +3290,11 @@ fn airNot(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
     func.finishAir(inst, result, &.{ty_op.operand});
 }
 
+fn airTrap(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
+    try func.addTag(.@"unreachable");
+    func.finishAir(inst, .none, &.{});
+}
+
 fn airBreakpoint(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
     // unsupported by wasm itfunc. Can be implemented once we support DWARF
     // for wasm