motiejus/zig
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pointers with bit offset contain length

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adds compile error when passing pointer that is byte-aligned
at the beginning but not the end to a function expecting
a fully byte aligned pointer

closes #261
This commit is contained in:
Andrew Kelley
2017-02-16 19:35:42 -05:00
parent 244362fed7
commit 0148f39df9
6 changed files with 74 additions and 57 deletions
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49
src/codegen.cpp
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@@ -1374,27 +1374,17 @@ static LLVMValueRef ir_render_load_ptr(CodeGen *g, IrExecutable *executable, IrI
assert(ptr_type->id == TypeTableEntryIdPointer);
bool is_volatile = ptr_type->data.pointer.is_volatile;
uint32_t bit_offset = ptr_type->data.pointer.bit_offset;
LLVMValueRef containing_int;
if (bit_offset == 0) {
LLVMValueRef result_val = get_handle_value(g, ptr, child_type, is_volatile);
if (LLVMGetTypeKind(LLVMTypeOf(result_val)) == LLVMIntegerTypeKind &&
LLVMGetTypeKind(child_type->type_ref) == LLVMIntegerTypeKind &&
LLVMGetIntTypeWidth(child_type->type_ref) < LLVMGetIntTypeWidth(LLVMTypeOf(result_val)))
{
containing_int = result_val;
} else {
return result_val;
}
} else {
assert(!handle_is_ptr(child_type));
containing_int = LLVMBuildLoad(g->builder, ptr, "");
LLVMSetVolatile(containing_int, is_volatile);
}
uint32_t unaligned_bit_count = ptr_type->data.pointer.unaligned_bit_count;
if (unaligned_bit_count == 0)
return get_handle_value(g, ptr, child_type, is_volatile);
uint32_t child_bit_count = type_size_bits(g, child_type);
assert(!handle_is_ptr(child_type));
LLVMValueRef containing_int = LLVMBuildLoad(g->builder, ptr, "");
LLVMSetVolatile(containing_int, is_volatile);
uint32_t bit_offset = ptr_type->data.pointer.bit_offset;
uint32_t host_bit_count = LLVMGetIntTypeWidth(LLVMTypeOf(containing_int));
uint32_t shift_amt = host_bit_count - bit_offset - child_bit_count;
uint32_t shift_amt = host_bit_count - bit_offset - unaligned_bit_count;
LLVMValueRef shift_amt_val = LLVMConstInt(LLVMTypeOf(containing_int), shift_amt, false);
LLVMValueRef shifted_value = LLVMBuildLShr(g->builder, containing_int, shift_amt_val, "");
@@ -1416,25 +1406,18 @@ static LLVMValueRef ir_render_store_ptr(CodeGen *g, IrExecutable *executable, Ir
if (handle_is_ptr(child_type))
return gen_struct_memcpy(g, value, ptr, child_type);
uint32_t bit_offset = ptr_type->data.pointer.bit_offset;
if (bit_offset == 0) {
LLVMTypeRef ptr_child_ref = LLVMGetElementType(LLVMTypeOf(ptr));
bool need_to_do_some_bit_stuff =
LLVMGetTypeKind(ptr_child_ref) == LLVMIntegerTypeKind &&
LLVMGetTypeKind(child_type->type_ref) == LLVMIntegerTypeKind &&
LLVMGetIntTypeWidth(child_type->type_ref) < LLVMGetIntTypeWidth(ptr_child_ref);
if (!need_to_do_some_bit_stuff) {
LLVMValueRef llvm_instruction = LLVMBuildStore(g->builder, value, ptr);
LLVMSetVolatile(llvm_instruction, ptr_type->data.pointer.is_volatile);
return nullptr;
}
uint32_t unaligned_bit_count = ptr_type->data.pointer.unaligned_bit_count;
if (unaligned_bit_count == 0) {
LLVMValueRef llvm_instruction = LLVMBuildStore(g->builder, value, ptr);
LLVMSetVolatile(llvm_instruction, ptr_type->data.pointer.is_volatile);
return nullptr;
}
LLVMValueRef containing_int = LLVMBuildLoad(g->builder, ptr, "");
uint32_t child_bit_count = type_size_bits(g, child_type);
uint32_t bit_offset = ptr_type->data.pointer.bit_offset;
uint32_t host_bit_count = LLVMGetIntTypeWidth(LLVMTypeOf(containing_int));
uint32_t shift_amt = host_bit_count - bit_offset - child_bit_count;
uint32_t shift_amt = host_bit_count - bit_offset - unaligned_bit_count;
LLVMValueRef shift_amt_val = LLVMConstInt(LLVMTypeOf(containing_int), shift_amt, false);
LLVMValueRef mask_val = LLVMConstAllOnes(child_type->type_ref);