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add debug safety for shortening casts

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closes #150
This commit is contained in:
Andrew Kelley
2016-05-09 08:44:41 -07:00
parent 9e905ab364
commit 56908dcb9d
7 changed files with 139 additions and 2 deletions
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54
src/codegen.cpp
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@@ -473,6 +473,18 @@ static LLVMValueRef gen_div_exact(CodeGen *g, AstNode *node) {
return gen_div(g, node, op1_val, op2_val, get_expr_type(op1_node), true);
}
static LLVMValueRef gen_truncate(CodeGen *g, AstNode *node) {
assert(node->type == NodeTypeFnCallExpr);
TypeTableEntry *dest_type = get_type_for_type_node(node->data.fn_call_expr.params.at(0));
AstNode *src_node = node->data.fn_call_expr.params.at(1);
LLVMValueRef src_val = gen_expr(g, src_node);
set_debug_source_node(g, node);
return LLVMBuildTrunc(g->builder, src_val, dest_type->type_ref, "");
}
static LLVMValueRef gen_shl_with_overflow(CodeGen *g, AstNode *node) {
assert(node->type == NodeTypeFnCallExpr);
@@ -661,6 +673,8 @@ static LLVMValueRef gen_builtin_fn_call_expr(CodeGen *g, AstNode *node) {
return gen_fence(g, node);
case BuiltinFnIdDivExact:
return gen_div_exact(g, node);
case BuiltinFnIdTruncate:
return gen_truncate(g, node);
}
zig_unreachable();
}
@@ -729,6 +743,24 @@ static LLVMValueRef gen_widen_or_shorten(CodeGen *g, AstNode *source_node, TypeT
zig_unreachable();
}
if (actual_bits >= wanted_bits && actual_type->id == TypeTableEntryIdInt &&
!wanted_type->data.integral.is_signed && actual_type->data.integral.is_signed &&
want_debug_safety(g, source_node))
{
set_debug_source_node(g, source_node);
LLVMValueRef zero = LLVMConstNull(actual_type->type_ref);
LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntSGE, expr_val, zero, "");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "SignCastOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "SignCastFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_debug_safety_crash(g);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
if (actual_bits == wanted_bits) {
return expr_val;
} else if (actual_bits < wanted_bits) {
@@ -752,7 +784,26 @@ static LLVMValueRef gen_widen_or_shorten(CodeGen *g, AstNode *source_node, TypeT
return LLVMBuildFPTrunc(g->builder, expr_val, wanted_type->type_ref, "");
} else if (actual_type->id == TypeTableEntryIdInt) {
set_debug_source_node(g, source_node);
return LLVMBuildTrunc(g->builder, expr_val, wanted_type->type_ref, "");
LLVMValueRef trunc_val = LLVMBuildTrunc(g->builder, expr_val, wanted_type->type_ref, "");
if (!want_debug_safety(g, source_node)) {
return trunc_val;
}
LLVMValueRef orig_val;
if (actual_type->data.integral.is_signed) {
orig_val = LLVMBuildSExt(g->builder, trunc_val, actual_type->type_ref, "");
} else {
orig_val = LLVMBuildZExt(g->builder, trunc_val, actual_type->type_ref, "");
}
LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntEQ, expr_val, orig_val, "");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "CastShortenOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "CastShortenFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_debug_safety_crash(g);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
return trunc_val;
} else {
zig_unreachable();
}
@@ -4568,6 +4619,7 @@ static void define_builtin_fns(CodeGen *g) {
create_builtin_fn_with_arg_count(g, BuiltinFnIdCmpExchange, "cmpxchg", 5);
create_builtin_fn_with_arg_count(g, BuiltinFnIdFence, "fence", 1);
create_builtin_fn_with_arg_count(g, BuiltinFnIdDivExact, "div_exact", 2);
create_builtin_fn_with_arg_count(g, BuiltinFnIdTruncate, "truncate", 2);
}
static void init(CodeGen *g, Buf *source_path) {