Commit 44f833129c

Andrew Kelley <andrew@ziglang.org>
2022-08-02 08:26:36
LLVM backends: work around poorly designed C API
As part of the Opaque Pointers upgrade documentation, LLVM says that the function LLVMGetGEPSourceElementType() can be used to obtain element type information in lieu of LLVMGetElementType(), however, this function actually returns the struct type, not the field type. The GEP instruction does store the information we need, however, this is not exposed in the C API. It seems like they accidentally exposed the wrong field, because one would never need the struct type since one must already pass it directly to the GEP instruction, so one will always have it handy, whereas one will usually not have the field type handy.
1 parent 9e40912
Changed files (5)
src/codegen/llvm/bindings.zig
@@ -242,8 +242,8 @@ pub const Value = opaque {
     pub const addFunctionAttr = ZigLLVMAddFunctionAttr;
     extern fn ZigLLVMAddFunctionAttr(Fn: *const Value, attr_name: [*:0]const u8, attr_value: [*:0]const u8) void;
 
-    pub const getGEPSourceElementType = LLVMGetGEPSourceElementType;
-    extern fn LLVMGetGEPSourceElementType(GEP: *const Value) *const Type;
+    pub const getGEPResultElementType = ZigLLVMGetGEPResultElementType;
+    extern fn ZigLLVMGetGEPResultElementType(GEP: *const Value) *const Type;
 };
 
 pub const Type = opaque {
src/codegen/llvm.zig
@@ -4901,7 +4901,7 @@ pub const FuncGen = struct {
             if (isByRef(payload_ty)) {
                 return payload_ptr;
             }
-            const load_inst = fg.builder.buildLoad(payload_ptr.getGEPSourceElementType(), payload_ptr, "");
+            const load_inst = fg.builder.buildLoad(payload_ptr.getGEPResultElementType(), payload_ptr, "");
             load_inst.setAlignment(payload_ty.abiAlignment(target));
             return load_inst;
         }
@@ -6043,7 +6043,7 @@ pub const FuncGen = struct {
             if (isByRef(payload_ty)) {
                 return payload_ptr;
             }
-            const load_inst = self.builder.buildLoad(payload_ptr.getGEPSourceElementType(), payload_ptr, "");
+            const load_inst = self.builder.buildLoad(payload_ptr.getGEPResultElementType(), payload_ptr, "");
             load_inst.setAlignment(payload_ty.abiAlignment(target));
             return load_inst;
         }
@@ -7820,7 +7820,7 @@ pub const FuncGen = struct {
             }
             const tag_index = @boolToInt(layout.tag_align < layout.payload_align);
             const tag_field_ptr = self.builder.buildStructGEP(llvm_un_ty, union_handle, tag_index, "");
-            return self.builder.buildLoad(tag_field_ptr.getGEPSourceElementType(), tag_field_ptr, "");
+            return self.builder.buildLoad(tag_field_ptr.getGEPResultElementType(), tag_field_ptr, "");
         } else {
             if (layout.payload_size == 0) {
                 return union_handle;
@@ -8671,7 +8671,7 @@ pub const FuncGen = struct {
             }
             const target = fg.dg.module.getTarget();
             const payload_alignment = payload_ty.abiAlignment(target);
-            const load_inst = fg.builder.buildLoad(payload_ptr.getGEPSourceElementType(), payload_ptr, "");
+            const load_inst = fg.builder.buildLoad(payload_ptr.getGEPResultElementType(), payload_ptr, "");
             load_inst.setAlignment(payload_alignment);
             return load_inst;
         }
src/stage1/codegen.cpp
@@ -1276,16 +1276,16 @@ static LLVMValueRef get_add_error_return_trace_addr_fn(CodeGen *g) {
     ZigType *slice_type = g->stack_trace_type->data.structure.fields[1]->type_entry;
     size_t ptr_field_index = slice_type->data.structure.fields[slice_ptr_index]->gen_index;
     LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(addresses_field_ptr),
+            ZigLLVMGetGEPResultElementType(addresses_field_ptr),
             addresses_field_ptr, (unsigned)ptr_field_index, "");
     size_t len_field_index = slice_type->data.structure.fields[slice_len_index]->gen_index;
     LLVMValueRef len_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(addresses_field_ptr),
+            ZigLLVMGetGEPResultElementType(addresses_field_ptr),
             addresses_field_ptr, (unsigned)len_field_index, "");
 
-    LLVMValueRef len_value = gen_load_untyped(g, LLVMGetGEPSourceElementType(len_field_ptr),
+    LLVMValueRef len_value = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(len_field_ptr),
             len_field_ptr, 0, false, "");
-    LLVMValueRef index_val = gen_load_untyped(g, LLVMGetGEPSourceElementType(index_field_ptr),
+    LLVMValueRef index_val = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(index_field_ptr),
             index_field_ptr, 0, false, "");
     LLVMValueRef len_val_minus_one = LLVMBuildSub(g->builder, len_value, LLVMConstInt(usize_type_ref, 1, false), "");
     LLVMValueRef masked_val = LLVMBuildAnd(g->builder, index_val, len_val_minus_one, "");
@@ -1293,7 +1293,7 @@ static LLVMValueRef get_add_error_return_trace_addr_fn(CodeGen *g) {
         masked_val,
     };
 
-    LLVMValueRef ptr_value = gen_load_untyped(g, LLVMGetGEPSourceElementType(ptr_field_ptr),
+    LLVMValueRef ptr_value = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(ptr_field_ptr),
             ptr_field_ptr, 0, false, "");
     LLVMValueRef address_slot = LLVMBuildInBoundsGEP2(g->builder, usize_type_ref, ptr_value, address_indices, 1, "");
 
@@ -1455,22 +1455,19 @@ static LLVMValueRef get_safety_crash_err_fn(CodeGen *g) {
     }
 
     // Fetch the error name from the global table
-    LLVMValueRef err_table_indices[] = {
-        LLVMConstNull(usize_ty->llvm_type),
-        err_val,
-    };
+    LLVMValueRef err_table_indices[] = { err_val };
     LLVMValueRef err_name_val = LLVMBuildInBoundsGEP2(g->builder,
             get_llvm_type(g, str_type),
             g->err_name_table, err_table_indices, 2, "");
 
     LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(err_name_val), err_name_val, slice_ptr_index, "");
-    LLVMValueRef err_name_ptr = gen_load_untyped(g, LLVMGetGEPSourceElementType(ptr_field_ptr),
+            ZigLLVMGetGEPResultElementType(err_name_val), err_name_val, slice_ptr_index, "");
+    LLVMValueRef err_name_ptr = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(ptr_field_ptr),
             ptr_field_ptr, 0, false, "");
 
     LLVMValueRef len_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(err_name_val), err_name_val, slice_len_index, "");
-    LLVMValueRef err_name_len = gen_load_untyped(g, LLVMGetGEPSourceElementType(len_field_ptr),
+            ZigLLVMGetGEPResultElementType(err_name_val), err_name_val, slice_len_index, "");
+    LLVMValueRef err_name_len = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(len_field_ptr),
                 len_field_ptr, 0, false, "");
 
     LLVMValueRef msg_prefix_len = LLVMConstInt(usize_ty->llvm_type, strlen(unwrap_err_msg_text), false);
@@ -2374,7 +2371,7 @@ static bool iter_function_params_c_abi(CodeGen *g, ZigType *fn_type, FnWalk *fn_
                         LLVMValueRef adjusted_ptr_to_struct = LLVMBuildStructGEP2(g->builder,
                                 abi_type, val, i, "");
                         LLVMValueRef loaded = LLVMBuildLoad2(g->builder,
-                                LLVMGetGEPSourceElementType(adjusted_ptr_to_struct),
+                                ZigLLVMGetGEPResultElementType(adjusted_ptr_to_struct),
                                 adjusted_ptr_to_struct, "");
                         fn_walk->data.call.gen_param_values->append(loaded);
                     }
@@ -2621,18 +2618,18 @@ static LLVMValueRef get_merge_err_ret_traces_fn_val(CodeGen *g) {
     ZigType *slice_type = g->stack_trace_type->data.structure.fields[1]->type_entry;
     size_t ptr_field_index = slice_type->data.structure.fields[slice_ptr_index]->gen_index;
     LLVMValueRef src_ptr_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(src_addresses_field_ptr),
+            ZigLLVMGetGEPResultElementType(src_addresses_field_ptr),
             src_addresses_field_ptr, (unsigned)ptr_field_index, "");
     size_t len_field_index = slice_type->data.structure.fields[slice_len_index]->gen_index;
     LLVMValueRef src_len_field_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(src_addresses_field_ptr),
+            ZigLLVMGetGEPResultElementType(src_addresses_field_ptr),
             src_addresses_field_ptr, (unsigned)len_field_index, "");
     LLVMValueRef src_index_val = LLVMBuildLoad2(g->builder,
-            LLVMGetGEPSourceElementType(src_index_field_ptr), src_index_field_ptr, "");
+            ZigLLVMGetGEPResultElementType(src_index_field_ptr), src_index_field_ptr, "");
     LLVMValueRef src_ptr_val = LLVMBuildLoad2(g->builder,
-            LLVMGetGEPSourceElementType(src_ptr_field_ptr), src_ptr_field_ptr, "");
+            ZigLLVMGetGEPResultElementType(src_ptr_field_ptr), src_ptr_field_ptr, "");
     LLVMValueRef src_len_val = LLVMBuildLoad2(g->builder,
-            LLVMGetGEPSourceElementType(src_len_field_ptr), src_len_field_ptr, "");
+            ZigLLVMGetGEPResultElementType(src_len_field_ptr), src_len_field_ptr, "");
     LLVMValueRef no_wrap_bit = LLVMBuildICmp(g->builder, LLVMIntULT, src_index_val, src_len_val, "");
     LLVMBasicBlockRef no_wrap_block = LLVMAppendBasicBlock(fn_val, "NoWrap");
     LLVMBasicBlockRef yes_wrap_block = LLVMAppendBasicBlock(fn_val, "YesWrap");
@@ -2658,7 +2655,7 @@ static LLVMValueRef get_merge_err_ret_traces_fn_val(CodeGen *g) {
     LLVMValueRef ptr_index = LLVMBuildLoad2(g->builder, usize_type_ref, frame_index_ptr, "");
     LLVMValueRef addr_ptr = LLVMBuildInBoundsGEP2(g->builder,
             usize_type_ref, src_ptr_val, &ptr_index, 1, "");
-    LLVMValueRef this_addr_val = LLVMBuildLoad2(g->builder, LLVMGetGEPSourceElementType(addr_ptr),
+    LLVMValueRef this_addr_val = LLVMBuildLoad2(g->builder, ZigLLVMGetGEPResultElementType(addr_ptr),
             addr_ptr, "");
     LLVMValueRef args[] = {dest_stack_trace_ptr, this_addr_val};
     ZigLLVMBuildCall(g->builder, LLVMGlobalGetValueType(add_error_return_trace_addr_fn_val),
@@ -4793,7 +4790,7 @@ static LLVMValueRef ir_render_elem_ptr(CodeGen *g, Stage1Air *executable, Stage1
             assert(len_index != SIZE_MAX);
             LLVMValueRef len_ptr = LLVMBuildStructGEP2(g->builder, get_llvm_type(g, array_type),
                     array_ptr, (unsigned)len_index, "");
-            LLVMValueRef len = gen_load_untyped(g, LLVMGetGEPSourceElementType(len_ptr), len_ptr,
+            LLVMValueRef len = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(len_ptr), len_ptr,
                     0, false, "");
             LLVMIntPredicate upper_op = (ptr_type->data.pointer.sentinel != nullptr) ? LLVMIntULE : LLVMIntULT;
             add_bounds_check(g, subscript_value, LLVMIntEQ, nullptr, upper_op, len);
@@ -4803,7 +4800,7 @@ static LLVMValueRef ir_render_elem_ptr(CodeGen *g, Stage1Air *executable, Stage1
         assert(ptr_index != SIZE_MAX);
         LLVMValueRef ptr_ptr = LLVMBuildStructGEP2(g->builder, get_llvm_type(g, array_type),
                 array_ptr, (unsigned)ptr_index, "");
-        LLVMValueRef ptr = gen_load_untyped(g, LLVMGetGEPSourceElementType(ptr_ptr), ptr_ptr, 0,
+        LLVMValueRef ptr = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(ptr_ptr), ptr_ptr, 0,
                 false, "");
         LLVMTypeRef elem_llvm_ty = get_llvm_type(g, ptr_type->data.pointer.child_type);
         return LLVMBuildInBoundsGEP2(g->builder, elem_llvm_ty, ptr, &subscript_value, 1, "");
@@ -4820,9 +4817,9 @@ static LLVMValueRef get_new_stack_addr(CodeGen *g, LLVMTypeRef new_stack_llvm_ty
     LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP2(g->builder, new_stack_llvm_ty, new_stack, (unsigned)slice_ptr_index, "");
     LLVMValueRef len_field_ptr = LLVMBuildStructGEP2(g->builder, new_stack_llvm_ty, new_stack, (unsigned)slice_len_index, "");
 
-    LLVMValueRef ptr_value = gen_load_untyped(g, LLVMGetGEPSourceElementType(ptr_field_ptr),
+    LLVMValueRef ptr_value = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(ptr_field_ptr),
             ptr_field_ptr, 0, false, "");
-    LLVMValueRef len_value = gen_load_untyped(g, LLVMGetGEPSourceElementType(len_field_ptr),
+    LLVMValueRef len_value = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(len_field_ptr),
             len_field_ptr, 0, false, "");
 
     LLVMValueRef ptr_addr = LLVMBuildPtrToInt(g->builder, ptr_value, LLVMTypeOf(len_value), "");
@@ -4962,7 +4959,7 @@ static void gen_init_stack_trace(CodeGen *g, LLVMValueRef trace_field_ptr, LLVMV
 
     LLVMValueRef addrs_slice_ptr = LLVMBuildStructGEP2(g->builder, stack_trace_llvm_ty, trace_field_ptr, 1, "");
     LLVMValueRef addrs_ptr_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(addrs_slice_ptr),
+            ZigLLVMGetGEPResultElementType(addrs_slice_ptr),
             addrs_slice_ptr, slice_ptr_index, "");
     LLVMValueRef indices[] = { LLVMConstNull(usize_type_ref), LLVMConstNull(usize_type_ref) };
     LLVMValueRef trace_field_addrs_as_ptr = LLVMBuildInBoundsGEP2(g->builder,
@@ -4970,7 +4967,7 @@ static void gen_init_stack_trace(CodeGen *g, LLVMValueRef trace_field_ptr, LLVMV
     LLVMBuildStore(g->builder, trace_field_addrs_as_ptr, addrs_ptr_ptr);
 
     LLVMValueRef addrs_len_ptr = LLVMBuildStructGEP2(g->builder,
-            LLVMGetGEPSourceElementType(addrs_slice_ptr),
+            ZigLLVMGetGEPResultElementType(addrs_slice_ptr),
             addrs_slice_ptr, slice_len_index, "");
     LLVMBuildStore(g->builder, LLVMConstInt(usize_type_ref, stack_trace_ptr_count, false), addrs_len_ptr);
 }
@@ -5064,7 +5061,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, Stage1Air *executable, Stage1AirI
                 LLVMValueRef frame_ptr_ptr = LLVMBuildStructGEP2(g->builder, frame_slice_llvm_ty,
                         frame_slice_ptr, slice_ptr_index, "");
                 LLVMValueRef frame_ptr = LLVMBuildLoad2(g->builder,
-                        LLVMGetGEPSourceElementType(frame_ptr_ptr), frame_ptr_ptr, "");
+                        ZigLLVMGetGEPResultElementType(frame_ptr_ptr), frame_ptr_ptr, "");
                 if (instruction->fn_entry == nullptr) {
                     anyframe_type = get_any_frame_type(g, src_return_type);
                     frame_result_loc = LLVMBuildBitCast(g->builder, frame_ptr, get_llvm_type(g, anyframe_type), "");
@@ -5127,7 +5124,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, Stage1Air *executable, Stage1AirI
 
                 // Store a zero in the awaiter's result ptr to indicate we do not need a copy made.
                 LLVMValueRef awaiter_ret_ptr = LLVMBuildStructGEP2(g->builder, frame_struct_llvm_ty, frame_result_loc, frame_ret_start + 1, "");
-                LLVMValueRef zero_ptr = LLVMConstNull(LLVMGetGEPSourceElementType(awaiter_ret_ptr));
+                LLVMValueRef zero_ptr = LLVMConstNull(ZigLLVMGetGEPResultElementType(awaiter_ret_ptr));
                 LLVMBuildStore(g->builder, zero_ptr, awaiter_ret_ptr);
             }
 
@@ -5145,7 +5142,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, Stage1Air *executable, Stage1AirI
 
         LLVMValueRef fn_ptr_ptr = LLVMBuildStructGEP2(g->builder, frame_struct_llvm_ty, frame_result_loc, frame_fn_ptr_index, "");
         LLVMValueRef bitcasted_fn_val = LLVMBuildBitCast(g->builder, fn_val,
-                LLVMGetGEPSourceElementType(fn_ptr_ptr), "");
+                ZigLLVMGetGEPResultElementType(fn_ptr_ptr), "");
         LLVMBuildStore(g->builder, bitcasted_fn_val, fn_ptr_ptr);
 
         LLVMValueRef resume_index_ptr = LLVMBuildStructGEP2(g->builder, frame_struct_llvm_ty, frame_result_loc, frame_resume_index, "");
@@ -5362,7 +5359,7 @@ static LLVMValueRef ir_render_call(CodeGen *g, Stage1Air *executable, Stage1AirI
                         get_llvm_type(g, instruction->new_stack->value->type->data.pointer.child_type),
                         frame_slice_ptr, slice_ptr_index, "");
                 frame_result_loc_uncasted = LLVMBuildLoad2(g->builder,
-                        LLVMGetGEPSourceElementType(frame_ptr_ptr), frame_ptr_ptr, "");
+                        ZigLLVMGetGEPResultElementType(frame_ptr_ptr), frame_ptr_ptr, "");
             }
             if (frame_result_loc_uncasted != nullptr) {
                 if (instruction->fn_entry != nullptr) {
@@ -5551,7 +5548,7 @@ static LLVMValueRef ir_render_union_field_ptr(CodeGen *g, Stage1Air *executable,
         LLVMValueRef tag_field_ptr = LLVMBuildStructGEP2(g->builder,
                 get_llvm_type(g, union_type),
                 union_ptr, union_type->data.unionation.gen_tag_index, "");
-        LLVMValueRef tag_value = gen_load_untyped(g, LLVMGetGEPSourceElementType(tag_field_ptr),
+        LLVMValueRef tag_value = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(tag_field_ptr),
                 tag_field_ptr, 0, false, "");
 
 
@@ -5787,7 +5784,7 @@ static LLVMValueRef gen_non_null_bit(CodeGen *g, ZigType *maybe_type, LLVMValueR
 
     LLVMValueRef maybe_field_ptr = LLVMBuildStructGEP2(g->builder,
             get_llvm_type(g, maybe_type), maybe_handle, maybe_null_index, "");
-    return gen_load_untyped(g, LLVMGetGEPSourceElementType(maybe_field_ptr), maybe_field_ptr, 0, false, "");
+    return gen_load_untyped(g, ZigLLVMGetGEPResultElementType(maybe_field_ptr), maybe_field_ptr, 0, false, "");
 }
 
 static LLVMValueRef ir_render_test_non_null(CodeGen *g, Stage1Air *executable,
@@ -6272,7 +6269,7 @@ static LLVMValueRef ir_render_align_cast(CodeGen *g, Stage1Air *executable, Stag
         LLVMValueRef ptr_val_ptr = LLVMBuildStructGEP2(g->builder,
                 get_llvm_type(g, instruction->target->value->type->data.pointer.child_type),
                 target_val, (unsigned)ptr_index, "");
-        ptr_val = gen_load_untyped(g, LLVMGetGEPSourceElementType(ptr_val_ptr), ptr_val_ptr, 0, false, "");
+        ptr_val = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(ptr_val_ptr), ptr_val_ptr, 0, false, "");
     } else {
         zig_unreachable();
     }
@@ -6759,7 +6756,7 @@ static LLVMValueRef ir_render_slice(CodeGen *g, Stage1Air *executable, Stage1Air
         if (!instruction->end || want_runtime_safety) {
             LLVMValueRef src_len_ptr = LLVMBuildStructGEP2(g->builder,
                     get_llvm_type(g, array_type), array_ptr, gen_len_index, "");
-            prev_end = gen_load_untyped(g, LLVMGetGEPSourceElementType(src_len_ptr), src_len_ptr, 0, false, "");
+            prev_end = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(src_len_ptr), src_len_ptr, 0, false, "");
         }
 
         LLVMValueRef start_val = ir_llvm_value(g, instruction->start);
@@ -6804,7 +6801,7 @@ static LLVMValueRef ir_render_slice(CodeGen *g, Stage1Air *executable, Stage1Air
 
             LLVMValueRef src_ptr_ptr = LLVMBuildStructGEP2(g->builder,
                     get_llvm_type(g, array_type), array_ptr, gen_ptr_index, "");
-            LLVMValueRef src_ptr = gen_load_untyped(g, LLVMGetGEPSourceElementType(src_ptr_ptr),
+            LLVMValueRef src_ptr = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(src_ptr_ptr),
                     src_ptr_ptr, 0, false, "");
 
             if (sentinel != nullptr) {
@@ -7005,7 +7002,7 @@ static LLVMValueRef ir_render_test_err(CodeGen *g, Stage1Air *executable, Stage1
     if (type_has_bits(g, payload_type)) {
         LLVMValueRef err_val_ptr = LLVMBuildStructGEP2(g->builder,
                 get_llvm_type(g, err_union_type), err_union_handle, err_union_err_index, "");
-        err_val = gen_load_untyped(g, LLVMGetGEPSourceElementType(err_val_ptr), err_val_ptr, 0, false, "");
+        err_val = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(err_val_ptr), err_val_ptr, 0, false, "");
     } else {
         err_val = err_union_handle;
     }
@@ -7077,7 +7074,7 @@ static LLVMValueRef ir_render_unwrap_err_payload(CodeGen *g, Stage1Air *executab
         if (type_has_bits(g, payload_type)) {
             LLVMValueRef err_val_ptr = LLVMBuildStructGEP2(g->builder, err_union_llvm_ty,
                     err_union_handle, err_union_err_index, "");
-            err_val = gen_load_untyped(g, LLVMGetGEPSourceElementType(err_val_ptr), err_val_ptr, 0, false, "");
+            err_val = gen_load_untyped(g, ZigLLVMGetGEPResultElementType(err_val_ptr), err_val_ptr, 0, false, "");
         } else {
             err_val = err_union_handle;
         }
@@ -7602,7 +7599,7 @@ static LLVMValueRef gen_await_early_return(CodeGen *g, Stage1AirInst *source_ins
         LLVMValueRef their_result_ptr_ptr = LLVMBuildStructGEP2(g->builder,
                 target_frame_struct_llvm_ty, target_frame_ptr, frame_ret_start, "");
         their_result_ptr = LLVMBuildLoad2(g->builder,
-                LLVMGetGEPSourceElementType(their_result_ptr_ptr), their_result_ptr_ptr, "");
+                ZigLLVMGetGEPResultElementType(their_result_ptr_ptr), their_result_ptr_ptr, "");
         if (result_loc != nullptr) {
             LLVMTypeRef ptr_u8 = LLVMPointerType(LLVMInt8Type(), 0);
             LLVMValueRef dest_ptr_casted = LLVMBuildBitCast(g->builder, result_loc, ptr_u8, "");
@@ -7620,7 +7617,7 @@ static LLVMValueRef gen_await_early_return(CodeGen *g, Stage1AirInst *source_ins
                 target_frame_struct_llvm_ty, target_frame_ptr,
                 frame_index_trace_arg(g, result_type), "");
         LLVMValueRef src_trace_ptr = LLVMBuildLoad2(g->builder,
-                LLVMGetGEPSourceElementType(their_trace_ptr_ptr), their_trace_ptr_ptr, "");
+                ZigLLVMGetGEPResultElementType(their_trace_ptr_ptr), their_trace_ptr_ptr, "");
         bool is_llvm_alloca;
         LLVMValueRef dest_trace_ptr = get_cur_err_ret_trace_val(g, source_instr->scope, &is_llvm_alloca);
         LLVMValueRef args[] = { dest_trace_ptr, src_trace_ptr };
@@ -7668,7 +7665,7 @@ static LLVMValueRef ir_render_await(CodeGen *g, Stage1Air *executable, Stage1Air
                 target_frame_ptr, frame_ret_start + 1, "");
         if (result_loc == nullptr) {
             // no copy needed
-            LLVMBuildStore(g->builder, LLVMConstNull(LLVMGetGEPSourceElementType(awaiter_ret_ptr_ptr)),
+            LLVMBuildStore(g->builder, LLVMConstNull(ZigLLVMGetGEPResultElementType(awaiter_ret_ptr_ptr)),
                     awaiter_ret_ptr_ptr);
         } else {
             LLVMBuildStore(g->builder, result_loc, awaiter_ret_ptr_ptr);
@@ -9353,7 +9350,7 @@ static void do_code_gen(CodeGen *g) {
             ZigType *slice_type = g->stack_trace_type->data.structure.fields[1]->type_entry;
             size_t ptr_field_index = slice_type->data.structure.fields[slice_ptr_index]->gen_index;
             LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP2(g->builder,
-                    LLVMGetGEPSourceElementType(addresses_field_ptr),
+                    ZigLLVMGetGEPResultElementType(addresses_field_ptr),
                     addresses_field_ptr, (unsigned)ptr_field_index, "");
             LLVMValueRef zero = LLVMConstNull(usize->llvm_type);
             LLVMValueRef indices[] = {zero, zero};
@@ -9364,7 +9361,7 @@ static void do_code_gen(CodeGen *g) {
 
             size_t len_field_index = slice_type->data.structure.fields[slice_len_index]->gen_index;
             LLVMValueRef len_field_ptr = LLVMBuildStructGEP2(g->builder,
-                    LLVMGetGEPSourceElementType(addresses_field_ptr),
+                    ZigLLVMGetGEPResultElementType(addresses_field_ptr),
                     addresses_field_ptr, (unsigned)len_field_index, "");
             gen_store(g, LLVMConstInt(usize->llvm_type, stack_trace_ptr_count, false), len_field_ptr, get_pointer_to_type(g, usize, false));
         }
@@ -9443,7 +9440,7 @@ static void do_code_gen(CodeGen *g) {
                             get_llvm_type(g, get_fn_frame_type(g, g->cur_fn)),
                             g->cur_frame_ptr,
                             frame_index_trace_arg(g, fn_type_id->return_type), "");
-                    LLVMValueRef zero_ptr = LLVMConstNull(LLVMGetGEPSourceElementType(trace_ptr_ptr));
+                    LLVMValueRef zero_ptr = LLVMConstNull(ZigLLVMGetGEPResultElementType(trace_ptr_ptr));
                     LLVMBuildStore(g->builder, zero_ptr, trace_ptr_ptr);
                 }
 
src/zig_llvm.cpp
@@ -1195,6 +1195,10 @@ void ZigLLVMSetCallElemTypeAttr(LLVMValueRef Call, size_t arg_index, LLVMTypeRef
             Attribute::get(call_inst->getContext(), Attribute::ElementType, llvm_type));
 }
 
+LLVMTypeRef ZigLLVMGetGEPResultElementType(LLVMValueRef GEP) {
+    return wrap(unwrap<GEPOperator>(GEP)->getResultElementType());
+}
+
 void ZigLLVMFunctionSetPrefixData(LLVMValueRef function, LLVMValueRef data) {
     unwrap<Function>(function)->setPrefixData(unwrap<Constant>(data));
 }
src/zig_llvm.h
@@ -322,6 +322,8 @@ ZIG_EXTERN_C void ZigLLVMAddSretAttr(LLVMValueRef fn_ref, LLVMTypeRef type_val);
 ZIG_EXTERN_C void ZigLLVMAddFunctionElemTypeAttr(LLVMValueRef fn_ref, size_t arg_index, LLVMTypeRef elem_ty);
 ZIG_EXTERN_C void ZigLLVMAddFunctionAttrCold(LLVMValueRef fn);
 
+ZIG_EXTERN_C LLVMTypeRef ZigLLVMGetGEPResultElementType(LLVMValueRef GEP);
+
 ZIG_EXTERN_C void ZigLLVMParseCommandLineOptions(size_t argc, const char *const *argv);