[clang-tools-extra] r329759 - [clang-tidy] Add a `android-comparison-in-temp-failure-retry` check
George Burgess IV via cfe-commits
cfe-commits at lists.llvm.org
Tue Apr 10 14:22:23 PDT 2018
Author: gbiv
Date: Tue Apr 10 14:22:22 2018
New Revision: 329759
URL: http://llvm.org/viewvc/llvm-project?rev=329759&view=rev
Log:
[clang-tidy] Add a `android-comparison-in-temp-failure-retry` check
This check attempts to catch buggy uses of the `TEMP_FAILURE_RETRY`
macro, which is provided by both Bionic and glibc.
Differential Revision: https://reviews.llvm.org/D45059
Added:
clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.cpp
clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.h
clang-tools-extra/trunk/docs/clang-tidy/checks/android-comparison-in-temp-failure-retry.rst
clang-tools-extra/trunk/test/clang-tidy/android-comparison-in-temp-failure-retry.c
Modified:
clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp
clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt
clang-tools-extra/trunk/docs/ReleaseNotes.rst
clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst
Modified: clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp?rev=329759&r1=329758&r2=329759&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/android/AndroidTidyModule.cpp Tue Apr 10 14:22:22 2018
@@ -22,6 +22,7 @@
#include "CloexecMemfdCreateCheck.h"
#include "CloexecOpenCheck.h"
#include "CloexecSocketCheck.h"
+#include "ComparisonInTempFailureRetryCheck.h"
using namespace clang::ast_matchers;
@@ -50,6 +51,8 @@ public:
"android-cloexec-memfd-create");
CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");
CheckFactories.registerCheck<CloexecSocketCheck>("android-cloexec-socket");
+ CheckFactories.registerCheck<ComparisonInTempFailureRetryCheck>(
+ "android-comparison-in-temp-failure-retry");
}
};
Modified: clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt?rev=329759&r1=329758&r2=329759&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt (original)
+++ clang-tools-extra/trunk/clang-tidy/android/CMakeLists.txt Tue Apr 10 14:22:22 2018
@@ -15,6 +15,7 @@ add_clang_library(clangTidyAndroidModule
CloexecMemfdCreateCheck.cpp
CloexecOpenCheck.cpp
CloexecSocketCheck.cpp
+ ComparisonInTempFailureRetryCheck.cpp
LINK_LIBS
clangAST
Added: clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.cpp?rev=329759&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.cpp (added)
+++ clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.cpp Tue Apr 10 14:22:22 2018
@@ -0,0 +1,84 @@
+//===--- ComparisonInTempFailureRetryCheck.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 "../utils/Matchers.h"
+#include "ComparisonInTempFailureRetryCheck.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 android {
+
+namespace {
+AST_MATCHER(BinaryOperator, isRHSATempFailureRetryArg) {
+ if (!Node.getLocStart().isMacroID())
+ return false;
+
+ const SourceManager &SM = Finder->getASTContext().getSourceManager();
+ if (!SM.isMacroArgExpansion(Node.getRHS()->IgnoreParenCasts()->getLocStart()))
+ return false;
+
+ const LangOptions &Opts = Finder->getASTContext().getLangOpts();
+ SourceLocation LocStart = Node.getLocStart();
+ while (LocStart.isMacroID()) {
+ SourceLocation Invocation = SM.getImmediateMacroCallerLoc(LocStart);
+ Token Tok;
+ if (!Lexer::getRawToken(SM.getSpellingLoc(Invocation), Tok, SM, Opts,
+ /*IgnoreWhiteSpace=*/true)) {
+ if (Tok.getKind() == tok::raw_identifier &&
+ Tok.getRawIdentifier() == "TEMP_FAILURE_RETRY")
+ return true;
+ }
+
+ LocStart = Invocation;
+ }
+ return false;
+}
+} // namespace
+
+void ComparisonInTempFailureRetryCheck::registerMatchers(MatchFinder *Finder) {
+ // Both glibc's and Bionic's TEMP_FAILURE_RETRY macros structurally look like:
+ //
+ // #define TEMP_FAILURE_RETRY(x) ({ \
+ // typeof(x) y; \
+ // do y = (x); \
+ // while (y == -1 && errno == EINTR); \
+ // y; \
+ // })
+ //
+ // (glibc uses `long int` instead of `typeof(x)` for the type of y).
+ //
+ // It's unclear how to walk up the AST from inside the expansion of `x`, and
+ // we need to not complain about things like TEMP_FAILURE_RETRY(foo(x == 1)),
+ // so we just match the assignment of `y = (x)` and inspect `x` from there.
+ Finder->addMatcher(
+ binaryOperator(
+ hasOperatorName("="),
+ hasRHS(ignoringParenCasts(
+ binaryOperator(matchers::isComparisonOperator()).bind("binop"))),
+ isRHSATempFailureRetryArg()),
+ this);
+}
+
+void ComparisonInTempFailureRetryCheck::check(
+ const MatchFinder::MatchResult &Result) {
+ const auto &BinOp = *Result.Nodes.getNodeAs<BinaryOperator>("binop");
+ diag(BinOp.getOperatorLoc(), "top-level comparison in TEMP_FAILURE_RETRY");
+
+ // FIXME: FixIts would be nice, but potentially nontrivial when nested macros
+ // happen, e.g. `TEMP_FAILURE_RETRY(IS_ZERO(foo()))`
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
Added: clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.h?rev=329759&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.h (added)
+++ clang-tools-extra/trunk/clang-tidy/android/ComparisonInTempFailureRetryCheck.h Tue Apr 10 14:22:22 2018
@@ -0,0 +1,36 @@
+//===--- ComparisonInTempFailureRetryCheck.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_ANDROID_COMPARISONINTEMPFAILURERETRYCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_COMPARISONINTEMPFAILURERETRYCHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// Attempts to catch calls to TEMP_FAILURE_RETRY with a top-level comparison
+/// operation, like `TEMP_FAILURE_RETRY(read(...) != N)`. In these cases, the
+/// comparison should go outside of the TEMP_FAILURE_RETRY.
+///
+/// TEMP_FAILURE_RETRY is a macro provided by both glibc and Bionic.
+class ComparisonInTempFailureRetryCheck : public ClangTidyCheck {
+public:
+ ComparisonInTempFailureRetryCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_COMPARISONINTEMPFAILURERETRYCHECK_H
Modified: clang-tools-extra/trunk/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/ReleaseNotes.rst?rev=329759&r1=329758&r2=329759&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/ReleaseNotes.rst (original)
+++ clang-tools-extra/trunk/docs/ReleaseNotes.rst Tue Apr 10 14:22:22 2018
@@ -69,6 +69,12 @@ Improvements to clang-tidy
- New module ``zircon`` for checks related to Fuchsia's Zircon kernel.
+- New :doc:`android-comparison-in-temp-failure-retry
+ <clang-tidy/checks/android-comparison-in-temp-failure-retry>` check
+
+ Diagnoses comparisons that appear to be incorrectly placed in the argument to
+ the ``TEMP_FAILURE_RETRY`` macro.
+
- New :doc:`bugprone-parent-virtual-call
<clang-tidy/checks/bugprone-parent-virtual-call>` check
Added: clang-tools-extra/trunk/docs/clang-tidy/checks/android-comparison-in-temp-failure-retry.rst
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/docs/clang-tidy/checks/android-comparison-in-temp-failure-retry.rst?rev=329759&view=auto
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/android-comparison-in-temp-failure-retry.rst (added)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/android-comparison-in-temp-failure-retry.rst Tue Apr 10 14:22:22 2018
@@ -0,0 +1,36 @@
+.. title:: clang-tidy - android-comparison-in-temp-failure-retry
+
+android-comparison-in-temp-failure-retry
+========================================
+
+Diagnoses comparisons that appear to be incorrectly placed in the argument to
+the ``TEMP_FAILURE_RETRY`` macro. Having such a use is incorrect in the vast
+majority of cases, and will often silently defeat the purpose of the
+``TEMP_FAILURE_RETRY`` macro.
+
+For context, ``TEMP_FAILURE_RETRY`` is `a convenience macro
+<https://www.gnu.org/software/libc/manual/html_node/Interrupted-Primitives.html>`_
+provided by both glibc and Bionic. Its purpose is to repeatedly run a syscall
+until it either succeeds, or fails for reasons other than being interrupted.
+
+Example buggy usage looks like:
+
+.. code-block:: c
+
+ char cs[1];
+ while (TEMP_FAILURE_RETRY(read(STDIN_FILENO, cs, sizeof(cs)) != 0)) {
+ // Do something with cs.
+ }
+
+Because TEMP_FAILURE_RETRY will check for whether the result *of the comparison*
+is ``-1``, and retry if so.
+
+If you encounter this, the fix is simple: lift the comparison out of the
+``TEMP_FAILURE_RETRY`` argument, like so:
+
+.. code-block:: c
+
+ char cs[1];
+ while (TEMP_FAILURE_RETRY(read(STDIN_FILENO, cs, sizeof(cs))) != 0) {
+ // Do something with cs.
+ }
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=329759&r1=329758&r2=329759&view=diff
==============================================================================
--- clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst (original)
+++ clang-tools-extra/trunk/docs/clang-tidy/checks/list.rst Tue Apr 10 14:22:22 2018
@@ -17,6 +17,7 @@ Clang-Tidy Checks
android-cloexec-memfd-create
android-cloexec-open
android-cloexec-socket
+ android-comparison-in-temp-failure-retry
boost-use-to-string
bugprone-argument-comment
bugprone-assert-side-effect
Added: clang-tools-extra/trunk/test/clang-tidy/android-comparison-in-temp-failure-retry.c
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/android-comparison-in-temp-failure-retry.c?rev=329759&view=auto
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/android-comparison-in-temp-failure-retry.c (added)
+++ clang-tools-extra/trunk/test/clang-tidy/android-comparison-in-temp-failure-retry.c Tue Apr 10 14:22:22 2018
@@ -0,0 +1,148 @@
+// RUN: %check_clang_tidy %s android-comparison-in-temp-failure-retry %t
+
+#define TEMP_FAILURE_RETRY(x) \
+ ({ \
+ typeof(x) __z; \
+ do \
+ __z = (x); \
+ while (__z == -1); \
+ __z; \
+ })
+
+int foo();
+int bar(int a);
+
+void test() {
+ int i;
+ TEMP_FAILURE_RETRY((i = foo()));
+ TEMP_FAILURE_RETRY(foo());
+ TEMP_FAILURE_RETRY((foo()));
+
+ TEMP_FAILURE_RETRY(foo() == 1);
+ // CHECK-MESSAGES: :[[@LINE-1]]:28: warning: top-level comparison in TEMP_FAILURE_RETRY [android-comparison-in-temp-failure-retry]
+ TEMP_FAILURE_RETRY((foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:29: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TEMP_FAILURE_RETRY((int)(foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+ TEMP_FAILURE_RETRY(bar(foo() == 1));
+ TEMP_FAILURE_RETRY((bar(foo() == 1)));
+ TEMP_FAILURE_RETRY((bar(foo() == 1)) == 1);
+ // CHECK-MESSAGES: :[[@LINE-1]]:40: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TEMP_FAILURE_RETRY(((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:41: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TEMP_FAILURE_RETRY((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:46: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define INDIRECT TEMP_FAILURE_RETRY
+ INDIRECT(foo());
+ INDIRECT((foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: top-level comparison in TEMP_FAILURE_RETRY
+ INDIRECT(bar(foo() == 1));
+ INDIRECT((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:36: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define TFR(x) TEMP_FAILURE_RETRY(x)
+ TFR(foo());
+ TFR((foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TFR(bar(foo() == 1));
+ TFR((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define ADD_TFR(x) (1 + TEMP_FAILURE_RETRY(x) + 1)
+ ADD_TFR(foo());
+ ADD_TFR(foo() == 1);
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+ ADD_TFR(bar(foo() == 1));
+ ADD_TFR((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:35: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define ADDP_TFR(x) (1 + TEMP_FAILURE_RETRY((x)) + 1)
+ ADDP_TFR(foo());
+ ADDP_TFR((foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+ ADDP_TFR(bar(foo() == 1));
+ ADDP_TFR((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:36: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define MACRO TEMP_FAILURE_RETRY(foo() == 1)
+ MACRO;
+ // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+ // Be sure that being a macro arg doesn't mess with this.
+#define ID(x) (x)
+ ID(ADDP_TFR(bar(foo() == 1)));
+ ID(ADDP_TFR(bar(foo() == 1) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:31: warning: top-level comparison in TEMP_FAILURE_RETRY
+ ID(MACRO);
+ // CHECK-MESSAGES: :[[@LINE-1]]:6: warning: top-level comparison in TEMP_FAILURE_RETRY
+
+#define CMP(x) x == 1
+ TEMP_FAILURE_RETRY(CMP(foo()));
+ // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: top-level comparison in TEMP_FAILURE_RETRY
+}
+
+// Be sure that it works inside of things like loops, if statements, etc.
+void control_flow() {
+ do {
+ if (TEMP_FAILURE_RETRY(foo())) {
+ }
+
+ if (TEMP_FAILURE_RETRY(foo() == 1)) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: top-level comparison in TEMP_FAILURE_RETRY
+ }
+
+ if (TEMP_FAILURE_RETRY(bar(foo() == 1))) {
+ }
+
+ if (TEMP_FAILURE_RETRY(bar(foo() == 1) == 1)) {
+ // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: top-level comparison in TEMP_FAILURE_RETRY
+ }
+ } while (TEMP_FAILURE_RETRY(foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:37: warning: top-level comparison in TEMP_FAILURE_RETRY
+}
+
+void with_nondependent_variable_type() {
+#undef TEMP_FAILURE_RETRY
+#define TEMP_FAILURE_RETRY(x) \
+ ({ \
+ long int __z; \
+ do \
+ __z = (x); \
+ while (__z == -1); \
+ __z; \
+ })
+
+ TEMP_FAILURE_RETRY((foo()));
+ TEMP_FAILURE_RETRY((int)(foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TEMP_FAILURE_RETRY((bar(foo() == 1)));
+ TEMP_FAILURE_RETRY((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:46: warning: top-level comparison in TEMP_FAILURE_RETRY
+}
+
+// I can't find a case where TEMP_FAILURE_RETRY is implemented like this, but if
+// we can cheaply support it, I don't see why not.
+void obscured_temp_failure_retry() {
+#undef TEMP_FAILURE_RETRY
+#define IMPL(x) \
+ ({ \
+ typeof(x) __z; \
+ do \
+ __z = (x); \
+ while (__z == -1); \
+ __z; \
+ })
+
+#define IMPL2(x) IMPL(x)
+#define TEMP_FAILURE_RETRY(x) IMPL2(x)
+ TEMP_FAILURE_RETRY((foo()));
+ TEMP_FAILURE_RETRY((int)(foo() == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:34: warning: top-level comparison in TEMP_FAILURE_RETRY
+ TEMP_FAILURE_RETRY((bar(foo() == 1)));
+ TEMP_FAILURE_RETRY((int)((bar(foo() == 1)) == 1));
+ // CHECK-MESSAGES: :[[@LINE-1]]:46: warning: top-level comparison in TEMP_FAILURE_RETRY
+}
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