JDevlieghere created this revision.
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This check emits a warning when memcpy is used and suggest replacing it with a
call to std::copy.
Using std::copy opens up the possibility of type-aware optimizations which are
not possible with memcpy.
Taken from: https://llvm.org/bugs/show_bug.cgi?id=22209
https://reviews.llvm.org/D22725
Files:
clang-tidy/misc/CMakeLists.txt
clang-tidy/misc/MiscTidyModule.cpp
clang-tidy/misc/ReplaceMemcpyCheck.cpp
clang-tidy/misc/ReplaceMemcpyCheck.h
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/misc-replace-memcpy.rst
test/clang-tidy/misc-replace-memcpy.cpp
Index: test/clang-tidy/misc-replace-memcpy.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/misc-replace-memcpy.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy %s misc-replace-memcpy %t
+
+#include <cstring>
+#include <algorithm>
+#include <stdio.h>
+
+void f() {
+ char foo[] = "foo", bar[3], baz[3];
+ std::memcpy(bar, foo, sizeof bar);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: Use std::copy instead of memcyp [misc-replace-memcpy]
+ // CHECK-FIXES: std::copy(foo, (foo) + (sizeof bar), bar);
+
+ bool b = false;
+ std::memcpy(baz, b ? foo : bar, 3);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: Use std::copy instead of memcyp [misc-replace-memcpy]
+ // CHECK-FIXES: std::copy(b ? foo : bar, (b ? foo : bar) + (3), baz);
+
+ memcpy(bar, foo, sizeof bar);
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: Use std::copy instead of memcyp [misc-replace-memcpy]
+ // CHECK-FIXES: std::copy(foo, (foo) + (sizeof bar), bar);
+
+ std::copy(foo, foo + sizeof bar, bar);
+}
Index: docs/clang-tidy/checks/misc-replace-memcpy.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/misc-replace-memcpy.rst
@@ -0,0 +1,18 @@
+.. title:: clang-tidy - misc-replace-memcpy
+
+misc-replace-memcpy
+===================
+
+Replaces ``memcpy`` with ``std::copy``. This allows the compiler to decide on
+the most performant implementationon. Parenthesis are added devensively to
+preclude the summation from taking precedence.
+
+Example:
+
+.. code:: c++
+
+ std::memcpy(dest, source, sizeof dest);
+
+ // transforms to:
+
+ std::copy(source, (source) + (sizeof dest), dest);
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -29,6 +29,7 @@
cppcoreguidelines-pro-type-static-cast-downcast
cppcoreguidelines-pro-type-union-access
cppcoreguidelines-pro-type-vararg
+ cppcoreguidelines-slicing
google-build-explicit-make-pair
google-build-namespaces
google-build-using-namespace
@@ -72,6 +73,7 @@
misc-non-copyable-objects
misc-pointer-and-integral-operation
misc-redundant-expression
+ misc-replace-memcpy
misc-sizeof-container
misc-sizeof-expression
misc-static-assert
Index: clang-tidy/misc/ReplaceMemcpyCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/misc/ReplaceMemcpyCheck.h
@@ -0,0 +1,38 @@
+//===--- ReplaceMemcpyCheck.h - clang-tidy-----------------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_REPLACE_MEMCPY_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_REPLACE_MEMCPY_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Replaces memcpy with std::copy
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/misc-replace-memcpy.html
+class ReplaceMemcpyCheck : public ClangTidyCheck {
+public:
+ ReplaceMemcpyCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+ static StringRef GetText(const Expr *Expression, const SourceManager &SM,
+ const LangOptions &LangOpts);
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_REPLACE_MEMCPY_H
Index: clang-tidy/misc/ReplaceMemcpyCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/misc/ReplaceMemcpyCheck.cpp
@@ -0,0 +1,60 @@
+//===--- ReplaceMemcpyCheck.cpp - clang-tidy-------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReplaceMemcpyCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Tooling/FixIt.h"
+
+#include <iostream>
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+void ReplaceMemcpyCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ callExpr(callee(functionDecl(hasName("memcpy")))).bind("expr"), this);
+}
+
+StringRef ReplaceMemcpyCheck::GetText(const Expr *Expression,
+ const SourceManager &SM,
+ const LangOptions &LangOpts) {
+ return Lexer::getSourceText(
+ CharSourceRange::getTokenRange(Expression->getSourceRange()), SM,
+ LangOpts);
+}
+
+void ReplaceMemcpyCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *MatchedExpr = Result.Nodes.getNodeAs<CallExpr>("expr");
+
+ if (MatchedExpr->getNumArgs() != 3)
+ return;
+
+ const auto &SM = *Result.SourceManager;
+ const auto &LangOptions = Result.Context->getLangOpts();
+
+ StringRef Destination = GetText(MatchedExpr->getArg(0), SM, LangOptions);
+ StringRef Source = GetText(MatchedExpr->getArg(1), SM, LangOptions);
+ StringRef Count = GetText(MatchedExpr->getArg(2), SM, LangOptions);
+
+ const std::string Insertion = "std::copy(" + Source.str() + ", (" +
+ Source.str() + ") + (" + Count.str() + "), " +
+ Destination.str() + ")";
+
+ diag(MatchedExpr->getExprLoc(), "Use std::copy instead of memcyp")
+ << FixItHint::CreateReplacement(MatchedExpr->getSourceRange(), Insertion);
+}
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/misc/MiscTidyModule.cpp
===================================================================
--- clang-tidy/misc/MiscTidyModule.cpp
+++ clang-tidy/misc/MiscTidyModule.cpp
@@ -13,6 +13,7 @@
#include "ArgumentCommentCheck.h"
#include "AssertSideEffectCheck.h"
#include "MisplacedConstCheck.h"
+#include "ReplaceMemcpyCheck.h"
#include "UnconventionalAssignOperatorCheck.h"
#include "BoolPointerImplicitConversionCheck.h"
#include "DanglingHandleCheck.h"
@@ -64,6 +65,8 @@
"misc-assert-side-effect");
CheckFactories.registerCheck<MisplacedConstCheck>(
"misc-misplaced-const");
+ CheckFactories.registerCheck<ReplaceMemcpyCheck>(
+ "misc-replace-memcpy");
CheckFactories.registerCheck<UnconventionalAssignOperatorCheck>(
"misc-unconventional-assign-operator");
CheckFactories.registerCheck<BoolPointerImplicitConversionCheck>(
Index: clang-tidy/misc/CMakeLists.txt
===================================================================
--- clang-tidy/misc/CMakeLists.txt
+++ clang-tidy/misc/CMakeLists.txt
@@ -4,6 +4,7 @@
ArgumentCommentCheck.cpp
AssertSideEffectCheck.cpp
MisplacedConstCheck.cpp
+ ReplaceMemcpyCheck.cpp
UnconventionalAssignOperatorCheck.cpp
BoolPointerImplicitConversionCheck.cpp
DanglingHandleCheck.cpp
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