From 08ad7afc1e90c68409e9dc869d9dc1dceb3e8564 Mon Sep 17 00:00:00 2001
From: Robin Voetter <robin@voetter.nl>
Date: Thu, 31 Oct 2024 20:24:37 +0100
Subject: [PATCH] spirv: forbid pointer arithmetic

---
 src/Sema.zig | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/Sema.zig b/src/Sema.zig
index 65805b6a67..771f4a0540 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -17605,6 +17605,24 @@ fn analyzePtrArithmetic(
         } else break :rs ptr_src;
     };
 
+    const target = zcu.getTarget();
+    if (target_util.arePointersLogical(target, ptr_info.flags.address_space)) {
+        return sema.failWithOwnedErrorMsg(block, msg: {
+            const msg = try sema.errMsg(op_src, "illegal pointer arithmetic on pointer of type '{}'", .{ptr_ty.fmt(pt)});
+            errdefer msg.destroy(sema.gpa);
+
+            const backend = target_util.zigBackend(target, zcu.comp.config.use_llvm);
+            try sema.errNote(op_src, msg, "arithmetic cannot be performed on pointers with address space '{s}' on target {s}-{s} by compiler backend {s}", .{
+                @tagName(ptr_info.flags.address_space),
+                target.cpu.arch.genericName(),
+                @tagName(target.os.tag),
+                @tagName(backend),
+            });
+
+            break :msg msg;
+        });
+    }
+
     try sema.requireRuntimeBlock(block, op_src, runtime_src);
     return block.addInst(.{
         .tag = air_tag,