Update prebuilt Clang to r416183b from Android.
https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef
clang 12.0.5 (based on r416183b) from build 7284624.
Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/include/clang-tidy/utils/ExprSequence.h b/linux-x64/clang/include/clang-tidy/utils/ExprSequence.h
new file mode 100644
index 0000000..7bb87ad
--- /dev/null
+++ b/linux-x64/clang/include/clang-tidy/utils/ExprSequence.h
@@ -0,0 +1,124 @@
+//===------------- ExprSequence.h - clang-tidy ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_EXPRSEQUENCE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_EXPRSEQUENCE_H
+
+#include "clang/Analysis/CFG.h"
+#include "clang/Lex/Lexer.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace utils {
+
+/// Provides information about the evaluation order of (sub-)expressions within
+/// a `CFGBlock`.
+///
+/// While a `CFGBlock` does contain individual `CFGElement`s for some
+/// sub-expressions, the order in which those `CFGElement`s appear reflects
+/// only one possible order in which the sub-expressions may be evaluated.
+/// However, we want to warn if any of the potential evaluation orders can lead
+/// to a use-after-move, not just the one contained in the `CFGBlock`.
+///
+/// This class implements only a simplified version of the C++ sequencing
+/// rules. The main limitation is that we do not distinguish between value
+/// computation and side effect -- see the "Implementation" section for more
+/// details.
+///
+/// Note: `SequenceChecker` from SemaChecking.cpp does a similar job (and much
+/// more thoroughly), but using it would require
+/// - Pulling `SequenceChecker` out into a header file (i.e. making it part of
+/// the API),
+/// - Removing the dependency of `SequenceChecker` on `Sema`, and
+/// - (Probably) modifying `SequenceChecker` to make it suitable to be used in
+/// this context.
+/// For the moment, it seems preferable to re-implement our own version of
+/// sequence checking that is special-cased to what we need here.
+///
+/// Implementation
+/// --------------
+///
+/// `ExprSequence` uses two types of sequencing edges between nodes in the AST:
+///
+/// - Every `Stmt` is assumed to be sequenced after its children. This is
+/// overly optimistic because the standard only states that value computations
+/// of operands are sequenced before the value computation of the operator,
+/// making no guarantees about side effects (in general).
+///
+/// For our purposes, this rule is sufficient, however, because this check is
+/// interested in operations on objects, which are generally performed through
+/// function calls (whether explicit and implicit). Function calls guarantee
+/// that the value computations and side effects for all function arguments
+/// are sequenced before the execution of the function.
+///
+/// - In addition, some `Stmt`s are known to be sequenced before or after
+/// their siblings. For example, the `Stmt`s that make up a `CompoundStmt`are
+/// all sequenced relative to each other. The function
+/// `getSequenceSuccessor()` implements these sequencing rules.
+class ExprSequence {
+public:
+ /// Initializes this `ExprSequence` with sequence information for the given
+ /// `CFG`. `Root` is the root statement the CFG was built from.
+ ExprSequence(const CFG *TheCFG, const Stmt *Root, ASTContext *TheContext);
+
+ /// Returns whether \p Before is sequenced before \p After.
+ bool inSequence(const Stmt *Before, const Stmt *After) const;
+
+ /// Returns whether \p After can potentially be evaluated after \p Before.
+ /// This is exactly equivalent to `!inSequence(After, Before)` but makes some
+ /// conditions read more naturally.
+ bool potentiallyAfter(const Stmt *After, const Stmt *Before) const;
+
+private:
+ // Returns the sibling of \p S (if any) that is directly sequenced after \p S,
+ // or nullptr if no such sibling exists. For example, if \p S is the child of
+ // a `CompoundStmt`, this would return the Stmt that directly follows \p S in
+ // the `CompoundStmt`.
+ //
+ // As the sequencing of many constructs that change control flow is already
+ // encoded in the `CFG`, this function only implements the sequencing rules
+ // for those constructs where sequencing cannot be inferred from the `CFG`.
+ const Stmt *getSequenceSuccessor(const Stmt *S) const;
+
+ const Stmt *resolveSyntheticStmt(const Stmt *S) const;
+
+ ASTContext *Context;
+ const Stmt *Root;
+
+ llvm::DenseMap<const Stmt *, const Stmt *> SyntheticStmtSourceMap;
+};
+
+/// Maps `Stmt`s to the `CFGBlock` that contains them. Some `Stmt`s may be
+/// contained in more than one `CFGBlock`; in this case, they are mapped to the
+/// innermost block (i.e. the one that is furthest from the root of the tree).
+class StmtToBlockMap {
+public:
+ /// Initializes the map for the given `CFG`.
+ StmtToBlockMap(const CFG *TheCFG, ASTContext *TheContext);
+
+ /// Returns the block that \p S is contained in. Some `Stmt`s may be contained
+ /// in more than one `CFGBlock`; in this case, this function returns the
+ /// innermost block (i.e. the one that is furthest from the root of the tree).
+ const CFGBlock *blockContainingStmt(const Stmt *S) const;
+
+private:
+ ASTContext *Context;
+
+ llvm::DenseMap<const Stmt *, const CFGBlock *> Map;
+};
+
+} // namespace utils
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_EXPRSEQUENCE_H