lebedev.ri created this revision.
lebedev.ri added reviewers: JonasToth, aaron.ballman, baloghadamsoftware.
lebedev.ri added projects: clang-tools-extra, OpenMP.
Herald added subscribers: jdoerfert, guansong, rnkovacs, xazax.hun, mgorny.
Herald added a project: clang.
Finally, we are here!
Analyzes OpenMP Structured Blocks and checks that no exception escapes
out of the Structured Block it was thrown in.
As per the OpenMP specification, structured block is an executable statement,
possibly compound, with a single entry at the top and a single exit at the
bottom. Which means, ``throw`` may not be used to to 'exit' out of the
structured block. If an exception is not caught in the same structured block
it was thrown in, the behaviour is undefined / implementation defined,
the program will likely terminate.
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D59466
Files:
clang-tidy/openmp/CMakeLists.txt
clang-tidy/openmp/ExceptionEscapeCheck.cpp
clang-tidy/openmp/ExceptionEscapeCheck.h
clang-tidy/openmp/OpenMPTidyModule.cpp
clang-tidy/utils/ExceptionAnalyzer.cpp
clang-tidy/utils/ExceptionAnalyzer.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/list.rst
docs/clang-tidy/checks/openmp-exception-escape.rst
test/clang-tidy/bugprone-exception-escape-openmp.cpp
test/clang-tidy/openmp-exception-escape.cpp
Index: test/clang-tidy/openmp-exception-escape.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/openmp-exception-escape.cpp
@@ -0,0 +1,126 @@
+// RUN: %check_clang_tidy %s openmp-exception-escape %t -- -extra-arg=-fopenmp -extra-arg=-fexceptions -config="{CheckOptions: [{key: openmp-exception-escape.IgnoredExceptions, value: 'ignored'}]}" --
+
+int thrower() {
+ throw 42;
+}
+
+class ignored {};
+namespace std {
+class bad_alloc {};
+} // namespace std
+
+void parallel() {
+#pragma omp parallel
+ thrower();
+ // CHECK-MESSAGES: :[[@LINE-2]]:9: warning: An exception thrown inside of the OpenMP 'parallel' region is not caught in that same region.
+}
+
+void ignore() {
+#pragma omp parallel
+ throw ignored();
+}
+
+void standalone_directive() {
+#pragma omp taskwait
+ throw ignored(); // not structured block
+}
+
+void ignore_alloc() {
+#pragma omp parallel
+ throw std::bad_alloc();
+}
+
+void parallel_caught() {
+#pragma omp parallel
+ {
+ try {
+ thrower();
+ } catch (...) {
+ }
+ }
+}
+
+void for_header(const int a) {
+ // Only the body of the loop counts.
+#pragma omp for
+ for (int i = 0; i < thrower(); i++)
+ ;
+}
+
+void forloop(const int a) {
+#pragma omp for
+ for (int i = 0; i < a; i++)
+ thrower();
+ // CHECK-MESSAGES: :[[@LINE-3]]:9: warning: An exception thrown inside of the OpenMP 'for' region is not caught in that same region.
+}
+
+void parallel_forloop(const int a) {
+#pragma omp parallel
+ {
+#pragma omp for
+ for (int i = 0; i < a; i++)
+ thrower();
+ thrower();
+ // CHECK-MESSAGES: :[[@LINE-6]]:9: warning: An exception thrown inside of the OpenMP 'parallel' region is not caught in that same region.
+ // CHECK-MESSAGES: :[[@LINE-5]]:9: warning: An exception thrown inside of the OpenMP 'for' region is not caught in that same region.
+ }
+}
+
+void parallel_forloop_caught(const int a) {
+#pragma omp parallel
+ {
+#pragma omp for
+ for (int i = 0; i < a; i++) {
+ try {
+ thrower();
+ } catch (...) {
+ }
+ }
+ thrower();
+ // CHECK-MESSAGES: :[[@LINE-10]]:9: warning: An exception thrown inside of the OpenMP 'parallel' region is not caught in that same region.
+ }
+}
+
+void parallel_caught_forloop(const int a) {
+#pragma omp parallel
+ {
+#pragma omp for
+ for (int i = 0; i < a; i++)
+ thrower();
+ try {
+ thrower();
+ } catch (...) {
+ }
+ // CHECK-MESSAGES: :[[@LINE-7]]:9: warning: An exception thrown inside of the OpenMP 'for' region is not caught in that same region.
+ }
+}
+
+void parallel_outercaught_forloop(const int a) {
+#pragma omp parallel
+ {
+ try {
+#pragma omp for
+ for (int i = 0; i < a; i++)
+ thrower();
+ thrower();
+ } catch (...) {
+ }
+ // CHECK-MESSAGES: :[[@LINE-6]]:9: warning: An exception thrown inside of the OpenMP 'for' region is not caught in that same region.
+ }
+}
+
+void parallel_outercaught_forloop_caught(const int a) {
+#pragma omp parallel
+ {
+ try {
+#pragma omp for
+ for (int i = 0; i < a; i++) {
+ try {
+ thrower();
+ } catch (...) {
+ }
+ }
+ } catch (...) {
+ }
+ }
+}
Index: test/clang-tidy/bugprone-exception-escape-openmp.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/bugprone-exception-escape-openmp.cpp
@@ -0,0 +1,29 @@
+// RUN: %check_clang_tidy %s bugprone-exception-escape %t -- -extra-arg=-fopenmp -extra-arg=-fexceptions --
+
+int thrower() {
+ throw 42;
+}
+
+void ok_parallel() {
+#pragma omp parallel
+ thrower();
+}
+
+void bad_for_header_XFAIL(const int a) {
+#pragma omp for
+ for (int i = 0; i < thrower(); i++)
+ ;
+ // FIXME: this really should be caught by bugprone-exception-escape.
+ // https://bugs.llvm.org/show_bug.cgi?id=41102
+}
+
+void ok_forloop(const int a) {
+#pragma omp for
+ for (int i = 0; i < a; i++)
+ thrower();
+}
+
+void some_exception_just_so_that_check_clang_tidy_shuts_up() noexcept {
+ thrower();
+}
+// CHECK-MESSAGES: :[[@LINE-3]]:6: warning: an exception may be thrown in function 'some_exception_just_so_that_check_clang_tidy_shuts_up' which should not throw exceptions
Index: docs/clang-tidy/checks/openmp-exception-escape.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/openmp-exception-escape.rst
@@ -0,0 +1,24 @@
+.. title:: clang-tidy - openmp-exception-escape
+
+openmp-exception-escape
+=======================
+
+Analyzes OpenMP Structured Blocks and checks that no exception escapes
+out of the Structured Block it was thrown in.
+
+As per the OpenMP specification, structured block is an executable statement,
+possibly compound, with a single entry at the top and a single exit at the
+bottom. Which means, ``throw`` may not be used to to 'exit' out of the
+structured block. If an exception is not caught in the same structured block
+it was thrown in, the behaviour is undefined / implementation defined,
+the program will likely terminate.
+
+WARNING! This check may be expensive on large source files.
+
+Options
+-------
+
+.. option:: IgnoredExceptions
+
+ Comma separated list containing type names which are not counted as thrown
+ exceptions in the check. Default value is an empty string.
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -227,6 +227,7 @@
objc-avoid-spinlock
objc-forbidden-subclassing
objc-property-declaration
+ openmp-exception-escape
openmp-use-default-none
performance-faster-string-find
performance-for-range-copy
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -127,6 +127,12 @@
<clang-tidy/checks/modernize-use-override>` now supports `OverrideSpelling`
and `FinalSpelling` options.
+- New :doc:`openmp-exception-escape
+ <clang-tidy/checks/openmp-exception-escape>` check.
+
+ Analyzes OpenMP Structured Blocks and checks that no exception escapes
+ out of the Structured Block it was thrown in.
+
- New :doc:`openmp-use-default-none
<clang-tidy/checks/openmp-use-default-none>` check.
Index: clang-tidy/utils/ExceptionAnalyzer.h
===================================================================
--- clang-tidy/utils/ExceptionAnalyzer.h
+++ clang-tidy/utils/ExceptionAnalyzer.h
@@ -128,7 +128,7 @@
IgnoredExceptions = std::move(ExceptionNames);
}
- ExceptionInfo analyze(const FunctionDecl *Func);
+ template <typename T> ExceptionInfo analyze(const T *Node);
private:
ExceptionInfo
@@ -138,10 +138,20 @@
throwsException(const Stmt *St, const ExceptionInfo::Throwables &Caught,
llvm::SmallSet<const FunctionDecl *, 32> &CallStack);
+ template <typename T>
+ void analyze(const T *Node, ExceptionInfo &ExceptionList);
+
bool IgnoreBadAlloc = true;
llvm::StringSet<> IgnoredExceptions;
std::map<const FunctionDecl *, ExceptionInfo> FunctionCache;
};
+
+extern template ExceptionAnalyzer::ExceptionInfo
+ExceptionAnalyzer::analyze<FunctionDecl>(const FunctionDecl *Func);
+
+extern template ExceptionAnalyzer::ExceptionInfo
+ExceptionAnalyzer::analyze<Stmt>(const Stmt *Stmt);
+
} // namespace utils
} // namespace tidy
} // namespace clang
Index: clang-tidy/utils/ExceptionAnalyzer.cpp
===================================================================
--- clang-tidy/utils/ExceptionAnalyzer.cpp
+++ clang-tidy/utils/ExceptionAnalyzer.cpp
@@ -204,10 +204,9 @@
return Results;
}
-ExceptionAnalyzer::ExceptionInfo
-ExceptionAnalyzer::analyze(const FunctionDecl *Func) {
- ExceptionInfo ExceptionList;
-
+template <>
+void ExceptionAnalyzer::analyze(const FunctionDecl *Func,
+ ExceptionInfo &ExceptionList) {
// Check if the function has already been analyzed and reuse that result.
if (FunctionCache.count(Func) == 0) {
llvm::SmallSet<const FunctionDecl *, 32> CallStack;
@@ -220,6 +219,20 @@
FunctionCache.insert(std::make_pair(Func, ExceptionList));
} else
ExceptionList = FunctionCache[Func];
+}
+
+template <>
+void ExceptionAnalyzer::analyze(const Stmt *Stmt,
+ ExceptionInfo &ExceptionList) {
+ llvm::SmallSet<const FunctionDecl *, 32> CallStack;
+ ExceptionList = throwsException(Stmt, ExceptionInfo::Throwables(), CallStack);
+}
+
+template <typename T>
+ExceptionAnalyzer::ExceptionInfo ExceptionAnalyzer::analyze(const T *Node) {
+ ExceptionInfo ExceptionList;
+
+ analyze<T>(Node, ExceptionList);
if (ExceptionList.getBehaviour() == State::NotThrowing ||
ExceptionList.getBehaviour() == State::Unknown)
@@ -231,6 +244,13 @@
return ExceptionList;
}
+
+template ExceptionAnalyzer::ExceptionInfo
+ExceptionAnalyzer::analyze<FunctionDecl>(const FunctionDecl *Func);
+
+template ExceptionAnalyzer::ExceptionInfo
+ExceptionAnalyzer::analyze<Stmt>(const Stmt *Stmt);
+
} // namespace utils
} // namespace tidy
Index: clang-tidy/openmp/OpenMPTidyModule.cpp
===================================================================
--- clang-tidy/openmp/OpenMPTidyModule.cpp
+++ clang-tidy/openmp/OpenMPTidyModule.cpp
@@ -9,6 +9,7 @@
#include "../ClangTidy.h"
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
+#include "ExceptionEscapeCheck.h"
#include "UseDefaultNoneCheck.h"
namespace clang {
@@ -19,6 +20,8 @@
class OpenMPModule : public ClangTidyModule {
public:
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
+ CheckFactories.registerCheck<ExceptionEscapeCheck>(
+ "openmp-exception-escape");
CheckFactories.registerCheck<UseDefaultNoneCheck>(
"openmp-use-default-none");
}
Index: clang-tidy/openmp/ExceptionEscapeCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/openmp/ExceptionEscapeCheck.h
@@ -0,0 +1,41 @@
+//===--- ExceptionEscapeCheck.h - clang-tidy --------------------*- C++ -*-===//
+//
+// 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_OPENMP_EXCEPTIONESCAPECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_OPENMP_EXCEPTIONESCAPECHECK_H
+
+#include "../ClangTidy.h"
+#include "../utils/ExceptionAnalyzer.h"
+
+namespace clang {
+namespace tidy {
+namespace openmp {
+
+/// Analyzes OpenMP Structured Blocks and checks that no exception escapes
+/// out of the Structured Block it was thrown in.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/openmp-exception-escape.html
+class ExceptionEscapeCheck : public ClangTidyCheck {
+public:
+ ExceptionEscapeCheck(StringRef Name, ClangTidyContext *Context);
+ void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ std::string RawIgnoredExceptions;
+
+ utils::ExceptionAnalyzer Tracer;
+};
+
+} // namespace openmp
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_OPENMP_EXCEPTIONESCAPECHECK_H
Index: clang-tidy/openmp/ExceptionEscapeCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/openmp/ExceptionEscapeCheck.cpp
@@ -0,0 +1,82 @@
+//===--- ExceptionEscapeCheck.cpp - 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "ExceptionEscapeCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/OpenMPClause.h"
+#include "clang/AST/Stmt.h"
+#include "clang/AST/StmtOpenMP.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersMacros.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace openmp {
+
+ExceptionEscapeCheck::ExceptionEscapeCheck(StringRef Name,
+ ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ RawIgnoredExceptions(Options.get("IgnoredExceptions", "")) {
+ llvm::SmallVector<StringRef, 8> FunctionsThatShouldNotThrowVec,
+ IgnoredExceptionsVec;
+
+ llvm::StringSet<> IgnoredExceptions;
+ StringRef(RawIgnoredExceptions).split(IgnoredExceptionsVec, ",", -1, false);
+ IgnoredExceptions.insert(IgnoredExceptionsVec.begin(),
+ IgnoredExceptionsVec.end());
+ Tracer.ignoreExceptions(std::move(IgnoredExceptions));
+ Tracer.ignoreBadAlloc(true);
+}
+
+void ExceptionEscapeCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "IgnoredExceptions", RawIgnoredExceptions);
+}
+
+void ExceptionEscapeCheck::registerMatchers(MatchFinder *Finder) {
+ // Don't register the check if OpenMP is not enabled; the OpenMP pragmas are
+ // completely ignored then, so no OpenMP entires will be present in the AST.
+ if (!getLangOpts().OpenMP)
+ return;
+ // Similarly, if C++ Exceptions are not enabled, nothing to do.
+ if (!getLangOpts().CPlusPlus || !getLangOpts().CXXExceptions)
+ return;
+
+ Finder->addMatcher(ompExecutableDirective(
+ unless(isStandaloneDirective()),
+ hasStructuredBlock(stmt().bind("structured-block")))
+ .bind("directive"),
+ this);
+}
+
+void ExceptionEscapeCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *Directive =
+ Result.Nodes.getNodeAs<OMPExecutableDirective>("directive");
+ assert(Directive && "Expected to match some OpenMP Executable directive.");
+ const auto *StructuredBlock =
+ Result.Nodes.getNodeAs<Stmt>("structured-block");
+ assert(StructuredBlock && "Expected to get soe OpenMP Structured Block.");
+
+ if (Tracer.analyze(StructuredBlock).getBehaviour() !=
+ utils::ExceptionAnalyzer::State::Throwing)
+ return; // No exceptions appear to escape out of the structured block.
+
+ // FIXME: We should provide more information about the exact location where
+ // the exception is thrown, maybe the full path the exception escapes
+
+ diag(Directive->getBeginLoc(),
+ "An exception thrown inside of the OpenMP '%0' region is not caught in "
+ "that same region.")
+ << getOpenMPDirectiveName(Directive->getDirectiveKind());
+}
+
+} // namespace openmp
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/openmp/CMakeLists.txt
===================================================================
--- clang-tidy/openmp/CMakeLists.txt
+++ clang-tidy/openmp/CMakeLists.txt
@@ -1,6 +1,7 @@
set(LLVM_LINK_COMPONENTS support)
add_clang_library(clangTidyOpenMPModule
+ ExceptionEscapeCheck.cpp
OpenMPTidyModule.cpp
UseDefaultNoneCheck.cpp
@@ -9,4 +10,5 @@
clangASTMatchers
clangBasic
clangTidy
+ clangTidyUtils
)
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