From 480e7eec65c02952b71ecc2f4ff2adccb6092a5f Mon Sep 17 00:00:00 2001
From: Cody Tapscott <topolarity@tapscott.me>
Date: Tue, 15 Mar 2022 14:00:33 -0700
Subject: stage2: Fix panic on initializing comptime fields in tuple

This resolves https://github.com/ziglang/zig/issues/11159

The problem was that:
  1. We were not correctly deleting the field stores after recognizing
     that an array initializer was a comptime-known value.
  2. LLVM was not checking that the final type had no runtime bits, and
     so would generate an invalid store.

This also adds several test cases for related bugs, just to check these
in for later work.
---
 src/codegen/llvm.zig | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'src/codegen')

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 692edd48c1..343e503aea 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -5422,21 +5422,22 @@ pub const FuncGen = struct {
         const bin_op = self.air.instructions.items(.data)[inst].bin_op;
         const dest_ptr = try self.resolveInst(bin_op.lhs);
         const ptr_ty = self.air.typeOf(bin_op.lhs);
+        const operand_ty = ptr_ty.childType();
+        if (!operand_ty.isFnOrHasRuntimeBitsIgnoreComptime()) return null;
 
         // TODO Sema should emit a different instruction when the store should
         // possibly do the safety 0xaa bytes for undefined.
         const val_is_undef = if (self.air.value(bin_op.rhs)) |val| val.isUndefDeep() else false;
         if (val_is_undef) {
-            const elem_ty = ptr_ty.childType();
             const target = self.dg.module.getTarget();
-            const elem_size = elem_ty.abiSize(target);
+            const operand_size = operand_ty.abiSize(target);
             const u8_llvm_ty = self.context.intType(8);
             const ptr_u8_llvm_ty = u8_llvm_ty.pointerType(0);
             const dest_ptr_u8 = self.builder.buildBitCast(dest_ptr, ptr_u8_llvm_ty, "");
             const fill_char = u8_llvm_ty.constInt(0xaa, .False);
             const dest_ptr_align = ptr_ty.ptrAlignment(target);
             const usize_llvm_ty = try self.dg.llvmType(Type.usize);
-            const len = usize_llvm_ty.constInt(elem_size, .False);
+            const len = usize_llvm_ty.constInt(operand_size, .False);
             _ = self.builder.buildMemSet(dest_ptr_u8, fill_char, len, dest_ptr_align, ptr_ty.isVolatilePtr());
             if (self.dg.module.comp.bin_file.options.valgrind) {
                 // TODO generate valgrind client request to mark byte range as undefined
-- 
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