OSLog.h source code [clang_source_code/include/clang/AST/OSLog.h]

1	//= OSLog.h - Analysis of calls to os_log builtins --- 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	// This file defines APIs for determining the layout of the data buffer for
10	// os_log() and os_trace().
11	//
12	//===----------------------------------------------------------------------===//
13
14	#ifndef LLVM_CLANG_ANALYSIS_ANALYSES_OSLOG_H
15	#define LLVM_CLANG_ANALYSIS_ANALYSES_OSLOG_H
16
17	#include "clang/AST/ASTContext.h"
18	#include "clang/AST/Expr.h"
19
20	namespace clang {
21	namespace analyze_os_log {
22
23	/// An OSLogBufferItem represents a single item in the data written by a call
24	/// to os_log() or os_trace().
25	class OSLogBufferItem {
26	public:
27	enum Kind {
28	// The item is a scalar (int, float, raw pointer, etc.). No further copying
29	// is required. This is the only kind allowed by os_trace().
30	ScalarKind = 0,
31
32	// The item is a count, which describes the length of the following item to
33	// be copied. A count may only be followed by an item of kind StringKind,
34	// WideStringKind, or PointerKind.
35	CountKind,
36
37	// The item is a pointer to a C string. If preceded by a count 'n',
38	// os_log() will copy at most 'n' bytes from the pointer.
39	StringKind,
40
41	// The item is a pointer to a block of raw data. This item must be preceded
42	// by a count 'n'. os_log() will copy exactly 'n' bytes from the pointer.
43	PointerKind,
44
45	// The item is a pointer to an Objective-C object. os_log() may retain the
46	// object for later processing.
47	ObjCObjKind,
48
49	// The item is a pointer to wide-char string.
50	WideStringKind,
51
52	// The item is corresponding to the '%m' format specifier, no value is
53	// populated in the buffer and the runtime is loading the errno value.
54	ErrnoKind,
55
56	// The item is a mask type.
57	MaskKind
58	};
59
60	enum {
61	// The item is marked "private" in the format string.
62	IsPrivate = 0x1,
63
64	// The item is marked "public" in the format string.
65	IsPublic = 0x2,
66
67	// The item is marked "sensitive" in the format string.
68	IsSensitive = 0x4 \| IsPrivate
69	};
70
71	private:
72	Kind TheKind = ScalarKind;
73	const Expr *TheExpr = nullptr;
74	CharUnits ConstValue;
75	CharUnits Size; // size of the data, not including the header bytes
76	unsigned Flags = 0;
77	StringRef MaskType;
78
79	public:
80	OSLogBufferItem(Kind kind, const Expr *expr, CharUnits size, unsigned flags,
81	StringRef maskType = StringRef())
82	: TheKind(kind), TheExpr(expr), Size(size), Flags(flags),
83	MaskType(maskType) {
84	(0) . __assert_fail ("((Flags == 0) \|\| (Flags == IsPrivate) \|\| (Flags == IsPublic) \|\| (Flags == IsSensitive)) && \"unexpected privacy flag\"", "/home/seafit/code_projects/clang_source/clang/include/clang/AST/OSLog.h", 86, __PRETTY_FUNCTION__))" file_link="../../../../include/assert.h.html#88" macro="true">assert(((Flags == 0) \|\| (Flags == IsPrivate) \|\| (Flags == IsPublic) \|\|
85	(0) . __assert_fail ("((Flags == 0) \|\| (Flags == IsPrivate) \|\| (Flags == IsPublic) \|\| (Flags == IsSensitive)) && \"unexpected privacy flag\"", "/home/seafit/code_projects/clang_source/clang/include/clang/AST/OSLog.h", 86, __PRETTY_FUNCTION__))" file_link="../../../../include/assert.h.html#88" macro="true"> (Flags == IsSensitive)) &&
86	(0) . __assert_fail ("((Flags == 0) \|\| (Flags == IsPrivate) \|\| (Flags == IsPublic) \|\| (Flags == IsSensitive)) && \"unexpected privacy flag\"", "/home/seafit/code_projects/clang_source/clang/include/clang/AST/OSLog.h", 86, __PRETTY_FUNCTION__))" file_link="../../../../include/assert.h.html#88" macro="true"> "unexpected privacy flag");
87	}
88
89	OSLogBufferItem(ASTContext &Ctx, CharUnits value, unsigned flags)
90	: TheKind(CountKind), ConstValue(value),
91	Size(Ctx.getTypeSizeInChars(Ctx.IntTy)), Flags(flags) {}
92
93	unsigned char getDescriptorByte() const {
94	unsigned char result = Flags;
95	result \|= ((unsigned)getKind()) << 4;
96	return result;
97	}
98
99	unsigned char getSizeByte() const { return size().getQuantity(); }
100
101	Kind getKind() const { return TheKind; }
102	bool getIsPrivate() const { return (Flags & IsPrivate) != 0; }
103
104	const Expr *getExpr() const { return TheExpr; }
105	CharUnits getConstValue() const { return ConstValue; }
106	CharUnits size() const { return Size; }
107
108	StringRef getMaskType() const { return MaskType; }
109	};
110
111	class OSLogBufferLayout {
112	public:
113	SmallVector<OSLogBufferItem, 4> Items;
114
115	enum Flags { HasPrivateItems = 1, HasNonScalarItems = 1 << 1 };
116
117	CharUnits size() const {
118	CharUnits result;
119	result += CharUnits::fromQuantity(2); // summary byte, num-args byte
120	for (auto &item : Items) {
121	// descriptor byte, size byte
122	result += item.size() + CharUnits::fromQuantity(2);
123	}
124	return result;
125	}
126
127	bool hasPrivateItems() const {
128	return llvm::any_of(
129	Items, [](const OSLogBufferItem &Item) { return Item.getIsPrivate(); });
130	}
131
132	bool hasNonScalarOrMask() const {
133	return llvm::any_of(Items, [](const OSLogBufferItem &Item) {
134	return Item.getKind() != OSLogBufferItem::ScalarKind \|\|
135	!Item.getMaskType().empty();
136	});
137	}
138
139	unsigned char getSummaryByte() const {
140	unsigned char result = 0;
141	if (hasPrivateItems())
142	result \|= HasPrivateItems;
143	if (hasNonScalarOrMask())
144	result \|= HasNonScalarItems;
145	return result;
146	}
147
148	unsigned char getNumArgsByte() const { return Items.size(); }
149	};
150
151	// Given a call 'E' to one of the builtins __builtin_os_log_format() or
152	// __builtin_os_log_format_buffer_size(), compute the layout of the buffer that
153	// the call will write into and store it in 'layout'. Returns 'false' if there
154	// was some error encountered while computing the layout, and 'true' otherwise.
155	bool computeOSLogBufferLayout(clang::ASTContext &Ctx, const clang::CallExpr *E,
156	OSLogBufferLayout &layout);
157
158	} // namespace analyze_os_log
159	} // namespace clang
160	#endif
161