From 65368683ad92b858d0a391cb29d37c0476784b40 Mon Sep 17 00:00:00 2001
From: r00ster91 <r00ster91@proton.me>
Date: Fri, 3 Mar 2023 18:35:03 +0100
Subject: 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.
---
 src/codegen/c.zig    | 6 ++++++
 src/codegen/llvm.zig | 8 ++++++++
 2 files changed, 14 insertions(+)

(limited to 'src/codegen')

diff --git a/src/codegen/c.zig b/src/codegen/c.zig
index cf428d4bd6..c0585c3a4a 100644
--- a/src/codegen/c.zig
+++ b/src/codegen/c.zig
@@ -2741,6 +2741,7 @@ fn genBodyInner(f: *Function, body: []const Air.Inst.Index) error{ AnalysisFail,
             .const_ty => unreachable, // excluded from function bodies
             .arg      => try airArg(f, inst),
 
+            .trap       => try airTrap(f.object.writer()),
             .breakpoint => try airBreakpoint(f.object.writer()),
             .ret_addr   => try airRetAddr(f, inst),
             .frame_addr => try airFrameAddress(f, inst),
@@ -4428,6 +4429,11 @@ fn airBitcast(f: *Function, inst: Air.Inst.Index) !CValue {
     return local;
 }
 
+fn airTrap(writer: anytype) !CValue {
+    try writer.writeAll("zig_trap();\n");
+    return .none;
+}
+
 fn airBreakpoint(writer: anytype) !CValue {
     try writer.writeAll("zig_breakpoint();\n");
     return .none;
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 6f240b88f5..1f8473ac32 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -4590,6 +4590,7 @@ pub const FuncGen = struct {
                 .block          => try self.airBlock(inst),
                 .br             => try self.airBr(inst),
                 .switch_br      => try self.airSwitchBr(inst),
+                .trap           => try self.airTrap(inst),
                 .breakpoint     => try self.airBreakpoint(inst),
                 .ret_addr       => try self.airRetAddr(inst),
                 .frame_addr     => try self.airFrameAddress(inst),
@@ -8256,6 +8257,13 @@ pub const FuncGen = struct {
         return fg.load(ptr, ptr_ty);
     }
 
+    fn airTrap(self: *FuncGen, inst: Air.Inst.Index) !?*llvm.Value {
+        _ = inst;
+        const llvm_fn = self.getIntrinsic("llvm.trap", &.{});
+        _ = self.builder.buildCall(llvm_fn.globalGetValueType(), llvm_fn, undefined, 0, .Cold, .Auto, "");
+        return null;
+    }
+
     fn airBreakpoint(self: *FuncGen, inst: Air.Inst.Index) !?*llvm.Value {
         _ = inst;
         const llvm_fn = self.getIntrinsic("llvm.debugtrap", &.{});
-- 
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