1//===-- Holder Class for manipulating va_lists ------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIBC_SRC___SUPPORT_ARG_LIST_H
10#define LLVM_LIBC_SRC___SUPPORT_ARG_LIST_H
11
12#include "src/__support/common.h"
13
14#include <stdarg.h>
15#include <stddef.h>
16#include <stdint.h>
17
18namespace LIBC_NAMESPACE {
19namespace internal {
20
21class ArgList {
22 va_list vlist;
23
24public:
25 LIBC_INLINE ArgList(va_list vlist) { va_copy(this->vlist, vlist); }
26 LIBC_INLINE ArgList(ArgList &other) { va_copy(this->vlist, other.vlist); }
27 LIBC_INLINE ~ArgList() { va_end(this->vlist); }
28
29 LIBC_INLINE ArgList &operator=(ArgList &rhs) {
30 va_copy(vlist, rhs.vlist);
31 return *this;
32 }
33
34 template <class T> LIBC_INLINE T next_var() { return va_arg(vlist, T); }
35};
36
37// Used for testing things that use an ArgList when it's impossible to know what
38// the arguments should be ahead of time. An example of this would be fuzzing,
39// since a function passed a random input could request unpredictable arguments.
40class MockArgList {
41 size_t arg_counter = 0;
42
43public:
44 LIBC_INLINE MockArgList() = default;
45 LIBC_INLINE MockArgList(va_list) { ; }
46 LIBC_INLINE MockArgList(MockArgList &other) {
47 arg_counter = other.arg_counter;
48 }
49 LIBC_INLINE ~MockArgList() = default;
50
51 LIBC_INLINE MockArgList &operator=(MockArgList &rhs) {
52 arg_counter = rhs.arg_counter;
53 return *this;
54 }
55
56 template <class T> LIBC_INLINE T next_var() {
57 ++arg_counter;
58 return T(arg_counter);
59 }
60
61 size_t read_count() const { return arg_counter; }
62};
63
64// Used for the GPU implementation of `printf`. This models a variadic list as a
65// simple array of pointers that are built manually by the implementation.
66class StructArgList {
67 void *ptr;
68 void *end;
69
70public:
71 LIBC_INLINE StructArgList(void *ptr, size_t size)
72 : ptr(ptr), end(reinterpret_cast<unsigned char *>(ptr) + size) {}
73 LIBC_INLINE StructArgList(const StructArgList &other) {
74 ptr = other.ptr;
75 end = other.end;
76 }
77 LIBC_INLINE StructArgList() = default;
78 LIBC_INLINE ~StructArgList() = default;
79
80 LIBC_INLINE StructArgList &operator=(const StructArgList &rhs) {
81 ptr = rhs.ptr;
82 return *this;
83 }
84
85 LIBC_INLINE void *get_ptr() const { return ptr; }
86
87 template <class T> LIBC_INLINE T next_var() {
88 ptr = reinterpret_cast<void *>(
89 ((reinterpret_cast<uintptr_t>(ptr) + alignof(T) - 1) / alignof(T)) *
90 alignof(T));
91
92 if (ptr >= end)
93 return T(-1);
94
95 T val = *reinterpret_cast<T *>(ptr);
96 ptr = reinterpret_cast<unsigned char *>(ptr) + sizeof(T);
97 return val;
98 }
99};
100
101} // namespace internal
102} // namespace LIBC_NAMESPACE
103
104#endif // LLVM_LIBC_SRC___SUPPORT_ARG_LIST_H
105

source code of libc/src/__support/arg_list.h