motiejus/zig
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ability to cast u8 slice to bigger slice

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This commit is contained in:
Andrew Kelley
2016-05-08 00:59:21 -07:00
parent aed96e3512
commit 18ed87c695
4 changed files with 57 additions and 14 deletions
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45
src/codegen.cpp
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@@ -888,6 +888,8 @@ static LLVMValueRef gen_cast_expr(CodeGen *g, AstNode *node) {
TypeTableEntry *actual_pointer_type = actual_type->data.structure.fields[0].type_entry;
TypeTableEntry *actual_child_type = actual_pointer_type->data.pointer.child_type;
TypeTableEntry *wanted_pointer_type = wanted_type->data.structure.fields[0].type_entry;
TypeTableEntry *wanted_child_type = wanted_pointer_type->data.pointer.child_type;
set_debug_source_node(g, node);
@@ -896,15 +898,6 @@ static LLVMValueRef gen_cast_expr(CodeGen *g, AstNode *node) {
int wanted_ptr_index = wanted_type->data.structure.fields[0].gen_index;
int wanted_len_index = wanted_type->data.structure.fields[1].gen_index;
LLVMValueRef src_len_ptr = LLVMBuildStructGEP(g->builder, expr_val, actual_len_index, "");
LLVMValueRef src_len = LLVMBuildLoad(g->builder, src_len_ptr, "");
LLVMValueRef src_size = LLVMConstInt(g->builtin_types.entry_isize->type_ref,
type_size(g, actual_child_type), false);
LLVMValueRef new_len = LLVMBuildMul(g->builder, src_len, src_size, "");
LLVMValueRef dest_len_ptr = LLVMBuildStructGEP(g->builder, cast_expr->tmp_ptr,
wanted_len_index, "");
LLVMBuildStore(g->builder, new_len, dest_len_ptr);
LLVMValueRef src_ptr_ptr = LLVMBuildStructGEP(g->builder, expr_val, actual_ptr_index, "");
LLVMValueRef src_ptr = LLVMBuildLoad(g->builder, src_ptr_ptr, "");
LLVMValueRef src_ptr_casted = LLVMBuildBitCast(g->builder, src_ptr,
@@ -913,6 +906,40 @@ static LLVMValueRef gen_cast_expr(CodeGen *g, AstNode *node) {
wanted_ptr_index, "");
LLVMBuildStore(g->builder, src_ptr_casted, dest_ptr_ptr);
LLVMValueRef src_len_ptr = LLVMBuildStructGEP(g->builder, expr_val, actual_len_index, "");
LLVMValueRef src_len = LLVMBuildLoad(g->builder, src_len_ptr, "");
uint64_t src_size = type_size(g, actual_child_type);
uint64_t dest_size = type_size(g, wanted_child_type);
LLVMValueRef new_len;
if (dest_size == 1) {
LLVMValueRef src_size_val = LLVMConstInt(g->builtin_types.entry_isize->type_ref, src_size, false);
new_len = LLVMBuildMul(g->builder, src_len, src_size_val, "");
} else if (src_size == 1) {
LLVMValueRef dest_size_val = LLVMConstInt(g->builtin_types.entry_isize->type_ref, dest_size, false);
if (want_debug_safety(g, node)) {
LLVMValueRef remainder_val = LLVMBuildURem(g->builder, src_len, dest_size_val, "");
LLVMValueRef zero = LLVMConstNull(g->builtin_types.entry_isize->type_ref);
LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntEQ, remainder_val, zero, "");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "SliceWidenOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "SliceWidenFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_debug_safety_crash(g);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
new_len = ZigLLVMBuildExactUDiv(g->builder, src_len, dest_size_val, "");
} else {
zig_unreachable();
}
LLVMValueRef dest_len_ptr = LLVMBuildStructGEP(g->builder, cast_expr->tmp_ptr,
wanted_len_index, "");
LLVMBuildStore(g->builder, new_len, dest_len_ptr);
return cast_expr->tmp_ptr;
}
case CastOpIntToFloat: