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add variable declaration initialization IR

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This commit is contained in:
Andrew Kelley
2016-10-20 01:13:39 -04:00
parent 682511d1b2
commit a9a6f77a1f
3 changed files with 58 additions and 7 deletions
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55
src/codegen.cpp
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@@ -2811,6 +2811,59 @@ static LLVMValueRef ir_render_un_op(CodeGen *g, IrExecutable *executable, IrInst
zig_unreachable();
}
static LLVMValueRef ir_render_decl_var(CodeGen *g, IrExecutable *executable,
IrInstructionDeclVar *decl_var_instruction)
{
VariableTableEntry *var = decl_var_instruction->var;
if (!type_has_bits(var->type))
return nullptr;
IrInstruction *init_value = decl_var_instruction->init_value;
bool have_init_expr = false;
bool want_zeroes = false;
ConstExprValue *const_val = &init_value->static_value;
if (!const_val->ok || const_val->special == ConstValSpecialOther)
have_init_expr = true;
if (const_val->ok && const_val->special == ConstValSpecialZeroes)
want_zeroes = true;
if (have_init_expr) {
gen_assign_raw(g, init_value->source_node, BinOpTypeAssign, var->value_ref,
ir_llvm_value(g, init_value), var->type, init_value->type_entry);
} else {
bool ignore_uninit = false;
// handle runtime stack allocation
bool want_safe = ir_want_debug_safety(g, &decl_var_instruction->base);
if (!ignore_uninit && (want_safe || want_zeroes)) {
TypeTableEntry *usize = g->builtin_types.entry_usize;
uint64_t size_bytes = LLVMStoreSizeOfType(g->target_data_ref, var->type->type_ref);
uint64_t align_bytes = get_memcpy_align(g, var->type);
// memset uninitialized memory to 0xa
LLVMTypeRef ptr_u8 = LLVMPointerType(LLVMInt8Type(), 0);
LLVMValueRef fill_char = LLVMConstInt(LLVMInt8Type(), want_zeroes ? 0x00 : 0xaa, false);
LLVMValueRef dest_ptr = LLVMBuildBitCast(g->builder, var->value_ref, ptr_u8, "");
LLVMValueRef byte_count = LLVMConstInt(usize->type_ref, size_bytes, false);
LLVMValueRef align_in_bytes = LLVMConstInt(LLVMInt32Type(), align_bytes, false);
LLVMValueRef params[] = {
dest_ptr,
fill_char,
byte_count,
align_in_bytes,
LLVMConstNull(LLVMInt1Type()), // is volatile
};
LLVMBuildCall(g->builder, g->memset_fn_val, params, 5, "");
}
}
gen_var_debug_decl(g, var);
return nullptr;
}
static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable, IrInstruction *instruction) {
set_debug_source_node(g, instruction->source_node);
@@ -2821,7 +2874,7 @@ static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable,
case IrInstructionIdReturn:
return ir_render_return(g, executable, (IrInstructionReturn *)instruction);
case IrInstructionIdDeclVar:
return nullptr;
return ir_render_decl_var(g, executable, (IrInstructionDeclVar *)instruction);
case IrInstructionIdLoadVar:
return ir_render_load_var(g, executable, (IrInstructionLoadVar *)instruction);
case IrInstructionIdBinOp: