[clang-tools-extra] r259362 - Add a new check, readability-redundant-control-flow, that check for some forms of redundant control flow statements. Currently checks for return statements at the end of a function with a void return type and continue statements at the end of looping statements.
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Mon Feb 1 07:31:16 PST 2016
Author: aaronballman
Date: Mon Feb 1 09:31:15 2016
New Revision: 259362
URL: http://llvm.org/viewvc/llvm-project?rev=259362&view=rev
Log:
Add a new check, readability-redundant-control-flow, that check for some forms of redundant control flow statements. Currently checks for return statements at the end of a function with a void return type and continue statements at the end of looping statements.
Patch by Richard Thomson.
Added:
clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.cpp
clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.h
clang-tools-extra/trunk/docs/clang-tidy/checks/readability-redundant-control-flow.rst
clang-tools-extra/trunk/test/clang-tidy/readability-redundant-control-flow.cpp
Modified:
clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt
clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp
clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
Modified: clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt?rev=259362&r1=259361&r2=259362&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt (original)
+++ clang-tools-extra/trunk/clang-tidy/readability/CMakeLists.txt Mon Feb 1 09:31:15 2016
@@ -11,6 +11,7 @@ add_clang_library(clangTidyReadabilityMo
NamedParameterCheck.cpp
NamespaceCommentCheck.cpp
ReadabilityTidyModule.cpp
+ RedundantControlFlowCheck.cpp
RedundantStringCStrCheck.cpp
RedundantSmartptrGetCheck.cpp
SimplifyBooleanExprCheck.cpp
Modified: clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp?rev=259362&r1=259361&r2=259362&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/readability/ReadabilityTidyModule.cpp Mon Feb 1 09:31:15 2016
@@ -18,6 +18,7 @@
#include "ImplicitBoolCastCheck.h"
#include "InconsistentDeclarationParameterNameCheck.h"
#include "NamedParameterCheck.h"
+#include "RedundantControlFlowCheck.h"
#include "RedundantSmartptrGetCheck.h"
#include "RedundantStringCStrCheck.h"
#include "SimplifyBooleanExprCheck.h"
@@ -44,6 +45,8 @@ public:
"readability-implicit-bool-cast");
CheckFactories.registerCheck<InconsistentDeclarationParameterNameCheck>(
"readability-inconsistent-declaration-parameter-name");
+ CheckFactories.registerCheck<RedundantControlFlowCheck>(
+ "readability-redundant-control-flow");
CheckFactories.registerCheck<UniqueptrDeleteReleaseCheck>(
"readability-uniqueptr-delete-release");
CheckFactories.registerCheck<readability::NamedParameterCheck>(
Added: clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.cpp?rev=259362&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.cpp (added)
+++ clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.cpp Mon Feb 1 09:31:15 2016
@@ -0,0 +1,99 @@
+//===--- RedundantControlFlowCheck.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 "RedundantControlFlowCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+namespace {
+
+const char *const RedundantReturnDiag = "redundant return statement at the end "
+ "of a function with a void return type";
+const char *const RedundantContinueDiag = "redundant continue statement at the "
+ "end of loop statement";
+
+bool isLocationInMacroExpansion(const SourceManager &SM, SourceLocation Loc) {
+ return SM.isMacroBodyExpansion(Loc) || SM.isMacroArgExpansion(Loc);
+}
+
+} // namespace
+
+void RedundantControlFlowCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ functionDecl(isDefinition(), returns(voidType()),
+ has(compoundStmt(hasAnySubstatement(returnStmt(
+ unless(has(expr()))))).bind("return"))),
+ this);
+ auto CompoundContinue =
+ has(compoundStmt(hasAnySubstatement(continueStmt())).bind("continue"));
+ Finder->addMatcher(
+ stmt(anyOf(forStmt(), cxxForRangeStmt(), whileStmt(), doStmt()),
+ CompoundContinue),
+ this);
+}
+
+void RedundantControlFlowCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const auto *Return = Result.Nodes.getNodeAs<CompoundStmt>("return"))
+ checkRedundantReturn(Result, Return);
+ else if (const auto *Continue =
+ Result.Nodes.getNodeAs<CompoundStmt>("continue"))
+ checkRedundantContinue(Result, Continue);
+}
+
+void RedundantControlFlowCheck::checkRedundantReturn(
+ const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
+ CompoundStmt::const_reverse_body_iterator last = Block->body_rbegin();
+ if (const auto *Return = dyn_cast<ReturnStmt>(*last))
+ issueDiagnostic(Result, Block, Return->getSourceRange(),
+ RedundantReturnDiag);
+}
+
+void RedundantControlFlowCheck::checkRedundantContinue(
+ const MatchFinder::MatchResult &Result, const CompoundStmt *Block) {
+ CompoundStmt::const_reverse_body_iterator last = Block->body_rbegin();
+ if (const auto *Continue = dyn_cast<ContinueStmt>(*last))
+ issueDiagnostic(Result, Block, Continue->getSourceRange(),
+ RedundantContinueDiag);
+}
+
+void RedundantControlFlowCheck::issueDiagnostic(
+ const MatchFinder::MatchResult &Result, const CompoundStmt *const Block,
+ const SourceRange &StmtRange, const char *const Diag) {
+ SourceManager &SM = *Result.SourceManager;
+ if (isLocationInMacroExpansion(SM, StmtRange.getBegin()))
+ return;
+
+ CompoundStmt::const_reverse_body_iterator Previous = ++Block->body_rbegin();
+ SourceLocation Start;
+ if (Previous != Block->body_rend())
+ Start = Lexer::findLocationAfterToken(
+ dyn_cast<Stmt>(*Previous)->getLocEnd(), tok::semi, SM,
+ Result.Context->getLangOpts(),
+ /*SkipTrailingWhitespaceAndNewLine=*/true);
+ else
+ Start = StmtRange.getBegin();
+ auto RemovedRange = CharSourceRange::getCharRange(
+ Start,
+ Lexer::findLocationAfterToken(StmtRange.getEnd(), tok::semi, SM,
+ Result.Context->getLangOpts(),
+ /*SkipTrailingWhitespaceAndNewLine=*/true));
+
+ diag(StmtRange.getBegin(), Diag) << FixItHint::CreateRemoval(RemovedRange);
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Added: clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.h?rev=259362&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.h (added)
+++ clang-tools-extra/trunk/clang-tidy/readability/RedundantControlFlowCheck.h Mon Feb 1 09:31:15 2016
@@ -0,0 +1,51 @@
+//===--- RedundantControlFlowCheck.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_READABILITY_REDUNDANT_CONTROL_FLOW_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANT_CONTROL_FLOW_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Eliminates redundant `return` statements at the end of a function that
+/// returns `void`.
+///
+/// Eliminates redundant `continue` statements at the end of a loop body.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-redundant-control-flow.html
+class RedundantControlFlowCheck : public ClangTidyCheck {
+public:
+ RedundantControlFlowCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ void
+ checkRedundantReturn(const ast_matchers::MatchFinder::MatchResult &Result,
+ const CompoundStmt *Block);
+
+ void
+ checkRedundantContinue(const ast_matchers::MatchFinder::MatchResult &Result,
+ const CompoundStmt *Block);
+
+ void issueDiagnostic(const ast_matchers::MatchFinder::MatchResult &Result,
+ const CompoundStmt *Block, const SourceRange &StmtRange,
+ const char *Diag);
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_REDUNDANT_CONTROL_FLOW_H
Modified: clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst?rev=259362&r1=259361&r2=259362&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst (original)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Mon Feb 1 09:31:15 2016
@@ -86,6 +86,7 @@ Clang-Tidy Checks
readability-implicit-bool-cast
readability-inconsistent-declaration-parameter-name
readability-named-parameter
+ readability-redundant-control-flow
readability-redundant-smartptr-get
readability-redundant-string-cstr
readability-simplify-boolean-expr
Added: clang-tools-extra/trunk/docs/clang-tidy/checks/readability-redundant-control-flow.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/readability-redundant-control-flow.rst?rev=259362&view=auto
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/readability-redundant-control-flow.rst (added)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/readability-redundant-control-flow.rst Mon Feb 1 09:31:15 2016
@@ -0,0 +1,50 @@
+.. title:: clang-tidy - readability-redundant-control-flow
+
+readability-redundant-control-flow
+==================================
+
+This check looks for procedures (functions returning no value) with `return`
+statements at the end of the function. Such `return` statements are redundant.
+
+Loop statements (`for`, `while`, `do while`) are checked for redundant
+`continue` statements at the end of the loop body.
+
+Examples:
+
+The following function `f` contains a redundant `return` statement:
+
+.. code:: c++
+
+ extern void g();
+ void f() {
+ g();
+ return;
+ }
+
+becomes
+
+.. code:: c++
+
+ extern void g();
+ void f() {
+ g();
+ }
+
+The following function `k` contains a redundant `continue` statement:
+
+.. code:: c++
+
+ void k() {
+ for (int i = 0; i < 10; ++i) {
+ continue;
+ }
+ }
+
+becomes
+
+.. code:: c++
+
+ void k() {
+ for (int i = 0; i < 10; ++i) {
+ }
+ }
Added: clang-tools-extra/trunk/test/clang-tidy/readability-redundant-control-flow.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/readability-redundant-control-flow.cpp?rev=259362&view=auto
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/readability-redundant-control-flow.cpp (added)
+++ clang-tools-extra/trunk/test/clang-tidy/readability-redundant-control-flow.cpp Mon Feb 1 09:31:15 2016
@@ -0,0 +1,222 @@
+// RUN: %check_clang_tidy %s readability-redundant-control-flow %t
+
+void g(int i);
+void j();
+
+void f() {
+ return;
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:3: warning: redundant return statement at the end of a function with a void return type [readability-redundant-control-flow]
+// CHECK-FIXES: {{^}}void f() {{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void g() {
+ f();
+ return;
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:3: warning: redundant return statement
+// CHECK-FIXES: {{^ }}f();{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void g(int i) {
+ if (i < 0) {
+ return;
+ }
+ if (i < 10) {
+ f();
+ }
+}
+
+int h() {
+ return 1;
+}
+
+void j() {
+}
+
+void k() {
+ for (int i = 0; i < 10; ++i) {
+ continue;
+ }
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement at the end of loop statement
+// CHECK-FIXES: {{^}} for (int i = 0; i < 10; ++i) {{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void k2() {
+ int v[10] = { 0 };
+ for (auto i : v) {
+ continue;
+ }
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement
+// CHECK-FIXES: {{^}} for (auto i : v) {{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void m() {
+ int i = 0;
+ do {
+ ++i;
+ continue;
+ } while (i < 10);
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement
+// CHECK-FIXES: {{^ do {$}}
+// CHECK-FIXES-NEXT: {{^}} ++i;{{$}}
+// CHECK-FIXES-NEXT: {{^ *}}} while (i < 10);{{$}}
+
+void p() {
+ int i = 0;
+ while (i < 10) {
+ ++i;
+ continue;
+ }
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement
+// CHECK-FIXES: {{^}} while (i < 10) {{{$}}
+// CHECK-FIXES-NEXT: {{^}} ++i;{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void im_not_dead(int i) {
+ if (i > 0) {
+ return;
+ }
+ g();
+}
+
+void im_still_not_dead(int i) {
+ for (int j = 0; j < 10; ++j) {
+ if (i < 10) {
+ continue;
+ }
+ g();
+ }
+}
+
+void im_dead(int i) {
+ if (i > 0) {
+ return;
+ g();
+ }
+ g();
+}
+
+void im_still_dead(int i) {
+ for (int j = 0; j < 10; ++j) {
+ if (i < 10) {
+ continue;
+ g();
+ }
+ g();
+ }
+}
+
+void void_return() {
+ return g();
+}
+
+void nested_return_unmolested() {
+ g();
+ {
+ g();
+ return;
+ }
+}
+
+void nested_continue_unmolested() {
+ for (int i = 0; i < 10; ++i) {
+ if (i < 5) {
+ continue;
+ }
+ }
+}
+
+#define MACRO_RETURN_UNMOLESTED(fn_) \
+ (fn_)(); \
+ return
+
+#define MACRO_CONTINUE_UNMOLESTED(x_) \
+ do { \
+ for (int i = 0; i < (x_); ++i) { \
+ continue; \
+ } \
+ } while (false)
+
+void macro_return() {
+ MACRO_RETURN_UNMOLESTED(g);
+}
+
+void macro_continue() {
+ MACRO_CONTINUE_UNMOLESTED(10);
+}
+
+#define MACRO_RETURN_ARG(stmt_) \
+ stmt_
+
+#define MACRO_CONTINUE_ARG(stmt_) \
+ do { \
+ for (int i = 0; i < 10; ++i) { \
+ stmt_; \
+ } \
+ } while (false)
+
+void macro_arg_return() {
+ MACRO_RETURN_ARG(return);
+}
+
+void macro_arg_continue() {
+ MACRO_CONTINUE_ARG(continue);
+}
+
+template <typename T>
+void template_return(T check) {
+ if (check < T(0)) {
+ return;
+ }
+ return;
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:3: warning: redundant return statement
+// CHECK-FIXES: {{^}} if (check < T(0)) {{{$}}
+// CHECK-FIXES-NEXT: {{^ return;$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+template <>
+void template_return(int check) {
+ if (check < 0) {
+ return;
+ }
+ return;
+}
+// CHECK-MESSAGES: :[[@LINE-2]]:3: warning: redundant return statement
+// CHECK-FIXES: {{^}} if (check < 0) {{{$}}
+// CHECK-FIXES-NEXT: {{^ return;$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+template <typename T>
+void template_loop(T end) {
+ for (T i = 0; i < end; ++i) {
+ continue;
+ }
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement
+// CHECK-FIXES: {{^}} for (T i = 0; i < end; ++i) {{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+template <>
+void template_loop(int end) {
+ for (int i = 0; i < end; ++i) {
+ continue;
+ }
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: redundant continue statement
+// CHECK-FIXES: {{^}} for (int i = 0; i < end; ++i) {{{$}}
+// CHECK-FIXES-NEXT: {{^ *}$}}
+
+void call_templates() {
+ template_return(10);
+ template_return(10.0f);
+ template_return(10.0);
+ template_loop(10);
+ template_loop(10L);
+ template_loop(10U);
+}
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