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more alignment improvements

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* add alignment capability for fn protos
 * add @alignCast
 * fix some ast rendering code
 * fix some ir rendering code
 * add error for pointer cast increasing alignment
 * update allocators in std to correctly align

See #37
This commit is contained in:
Andrew Kelley
2017-08-29 23:33:25 -04:00
parent 910a96f046
commit 898d65baa9
13 changed files with 418 additions and 69 deletions
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71
src/codegen.cpp
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@@ -688,6 +688,8 @@ static Buf *panic_msg_buf(PanicMsgId msg_id) {
return buf_create_from_str("reached unreachable code");
case PanicMsgIdInvalidErrorCode:
return buf_create_from_str("invalid error code");
case PanicMsgIdIncorrectAlignment:
return buf_create_from_str("incorrect alignment");
}
zig_unreachable();
}
@@ -2605,6 +2607,72 @@ static LLVMValueRef ir_render_field_parent_ptr(CodeGen *g, IrExecutable *executa
}
}
static LLVMValueRef get_default_aligned_load(CodeGen *g, LLVMValueRef ptr) {
LLVMValueRef result = LLVMBuildLoad(g->builder, ptr, "");
LLVMSetAlignment(result, LLVMABIAlignmentOfType(g->target_data_ref, LLVMGetElementType(LLVMTypeOf(ptr))));
return result;
}
static LLVMValueRef ir_render_align_cast(CodeGen *g, IrExecutable *executable, IrInstructionAlignCast *instruction) {
LLVMValueRef target_val = ir_llvm_value(g, instruction->target);
assert(target_val);
bool want_debug_safety = ir_want_debug_safety(g, &instruction->base);
if (!want_debug_safety) {
return target_val;
}
TypeTableEntry *target_type = instruction->base.value.type;
uint32_t align_bytes;
LLVMValueRef ptr_val;
if (target_type->id == TypeTableEntryIdPointer) {
align_bytes = target_type->data.pointer.alignment;
ptr_val = target_val;
} else if (target_type->id == TypeTableEntryIdFn) {
align_bytes = target_type->data.fn.fn_type_id.alignment;
ptr_val = target_val;
} else if (target_type->id == TypeTableEntryIdMaybe &&
target_type->data.maybe.child_type->id == TypeTableEntryIdPointer)
{
align_bytes = target_type->data.maybe.child_type->data.pointer.alignment;
ptr_val = target_val;
} else if (target_type->id == TypeTableEntryIdMaybe &&
target_type->data.maybe.child_type->id == TypeTableEntryIdFn)
{
align_bytes = target_type->data.maybe.child_type->data.fn.fn_type_id.alignment;
ptr_val = target_val;
} else if (target_type->id == TypeTableEntryIdStruct && target_type->data.structure.is_slice) {
TypeTableEntry *slice_ptr_type = target_type->data.structure.fields[slice_ptr_index].type_entry;
align_bytes = slice_ptr_type->data.pointer.alignment;
size_t ptr_index = target_type->data.structure.fields[slice_ptr_index].gen_index;
LLVMValueRef ptr_val_ptr = LLVMBuildStructGEP(g->builder, target_val, (unsigned)ptr_index, "");
ptr_val = get_default_aligned_load(g, ptr_val_ptr);
} else {
zig_unreachable();
}
assert(align_bytes != 1);
TypeTableEntry *usize = g->builtin_types.entry_usize;
LLVMValueRef ptr_as_int_val = LLVMBuildPtrToInt(g->builder, ptr_val, usize->type_ref, "");
LLVMValueRef alignment_minus_1 = LLVMConstInt(usize->type_ref, align_bytes - 1, false);
LLVMValueRef anded_val = LLVMBuildAnd(g->builder, ptr_as_int_val, alignment_minus_1, "");
LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntEQ, anded_val, LLVMConstNull(usize->type_ref), "");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "AlignCastOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "AlignCastFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_debug_safety_crash(g, PanicMsgIdIncorrectAlignment);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
return target_val;
}
static LLVMAtomicOrdering to_LLVMAtomicOrdering(AtomicOrder atomic_order) {
switch (atomic_order) {
@@ -3350,6 +3418,8 @@ static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable,
return ir_render_enum_tag_name(g, executable, (IrInstructionEnumTagName *)instruction);
case IrInstructionIdFieldParentPtr:
return ir_render_field_parent_ptr(g, executable, (IrInstructionFieldParentPtr *)instruction);
case IrInstructionIdAlignCast:
return ir_render_align_cast(g, executable, (IrInstructionAlignCast *)instruction);
}
zig_unreachable();
}
@@ -4633,6 +4703,7 @@ static void define_builtin_fns(CodeGen *g) {
create_builtin_fn(g, BuiltinFnIdShlExact, "shlExact", 2);
create_builtin_fn(g, BuiltinFnIdShrExact, "shrExact", 2);
create_builtin_fn(g, BuiltinFnIdSetEvalBranchQuota, "setEvalBranchQuota", 1);
create_builtin_fn(g, BuiltinFnIdAlignCast, "alignCast", 2);
}
static const char *bool_to_str(bool b) {