This revision was automatically updated to reflect the committed changes.
Closed by commit rC327309: [analyzer] Move the GCDAsyncSemaphoreChecker to
optin.performance (authored by george.karpenkov, committed by ).
Herald added a subscriber: cfe-commits.
Changed prior to commit:
https://reviews.llvm.org/D44228?vs=137823&id=138063#toc
Repository:
rC Clang
https://reviews.llvm.org/D44228
Files:
include/clang/StaticAnalyzer/Checkers/Checkers.td
lib/StaticAnalyzer/Checkers/CMakeLists.txt
lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
lib/StaticAnalyzer/Checkers/GCDAsyncSemaphoreChecker.cpp
test/Analysis/gcdantipatternchecker_test.m
test/Analysis/gcdasyncsemaphorechecker_test.m
Index: include/clang/StaticAnalyzer/Checkers/Checkers.td
===================================================================
--- include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -610,12 +610,12 @@
} // end "osx.cocoa"
-let ParentPackage = OSXAlpha in {
+let ParentPackage = Performance in {
-def GCDAsyncSemaphoreChecker : Checker<"GCDAsyncSemaphore">,
- HelpText<"Checker for performance anti-pattern when using semaphors from async API">,
- DescFile<"GCDAsyncSemaphoreChecker.cpp">;
-} // end "alpha.osx"
+def GCDAntipattern : Checker<"GCDAntipattern">,
+ HelpText<"Check for performance anti-patterns when using Grand Central Dispatch">,
+ DescFile<"GCDAntipatternChecker.cpp">;
+} // end "optin.performance"
let ParentPackage = CocoaAlpha in {
Index: test/Analysis/gcdantipatternchecker_test.m
===================================================================
--- test/Analysis/gcdantipatternchecker_test.m
+++ test/Analysis/gcdantipatternchecker_test.m
@@ -0,0 +1,266 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,optin.performance.GCDAntipattern %s -fblocks -verify
+typedef signed char BOOL;
+@protocol NSObject - (BOOL)isEqual:(id)object; @end
+@interface NSObject <NSObject> {}
++(id)alloc;
+-(id)init;
+-(id)autorelease;
+-(id)copy;
+-(id)retain;
+@end
+
+typedef int dispatch_semaphore_t;
+typedef void (^block_t)();
+
+dispatch_semaphore_t dispatch_semaphore_create(int);
+void dispatch_semaphore_wait(dispatch_semaphore_t, int);
+void dispatch_semaphore_signal(dispatch_semaphore_t);
+
+void func(void (^)(void));
+void func_w_typedef(block_t);
+
+int coin();
+
+void use_semaphor_antipattern() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+// It's OK to use pattern in tests.
+// We simply match the containing function name against ^test.
+void test_no_warning() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100);
+}
+
+void use_semaphor_antipattern_multiple_times() {
+ dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema1);
+ });
+ dispatch_semaphore_wait(sema1, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+
+ dispatch_semaphore_t sema2 = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema2);
+ });
+ dispatch_semaphore_wait(sema2, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void use_semaphor_antipattern_multiple_wait() {
+ dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema1);
+ });
+ // FIXME: multiple waits on same semaphor should not raise a warning.
+ dispatch_semaphore_wait(sema1, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+ dispatch_semaphore_wait(sema1, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void warn_incorrect_order() {
+ // FIXME: ASTMatchers do not allow ordered matching, so would match even
+ // if out of order.
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+}
+
+void warn_w_typedef() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func_w_typedef(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void warn_nested_ast() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ if (coin()) {
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ } else {
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ }
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void use_semaphore_assignment() {
+ dispatch_semaphore_t sema;
+ sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void use_semaphore_assignment_init() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+ sema = dispatch_semaphore_create(1);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void differentsemaphoreok() {
+ dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
+ dispatch_semaphore_t sema2 = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema1);
+ });
+ dispatch_semaphore_wait(sema2, 100); // no-warning
+}
+
+void nosignalok() {
+ dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
+ dispatch_semaphore_wait(sema1, 100);
+}
+
+void nowaitok() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+}
+
+void noblockok() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+ dispatch_semaphore_signal(sema);
+ dispatch_semaphore_wait(sema, 100);
+}
+
+void storedblockok() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+ block_t b = ^{
+ dispatch_semaphore_signal(sema);
+ };
+ dispatch_semaphore_wait(sema, 100);
+}
+
+void passed_semaphore_ok(dispatch_semaphore_t sema) {
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100);
+}
+
+void warn_with_cast() {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal((int)sema);
+ });
+ dispatch_semaphore_wait((int)sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+@interface MyInterface1 : NSObject
+-(void)use_method_warn;
+-(void)use_objc_callback_warn;
+-(void)testNoWarn;
+-(void)acceptBlock:(block_t)callback;
+@end
+
+@implementation MyInterface1
+
+-(void)use_method_warn {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+-(void)testNoWarn {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100);
+}
+
+-(void)acceptBlock:(block_t) callback {
+ callback();
+}
+
+-(void)use_objc_callback_warn {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ [self acceptBlock:^{
+ dispatch_semaphore_signal(sema);
+ }];
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+
+void use_objc_and_c_callback(MyInterface1 *t) {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+
+ dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
+
+ [t acceptBlock:^{
+ dispatch_semaphore_signal(sema1);
+ }];
+ dispatch_semaphore_wait(sema1, 100); // expected-warning{{Waiting on a semaphore with Grand Central Dispatch creates useless threads and is subject to priority inversion}}
+}
+@end
+
+// No warnings: class name contains "test"
+@interface Test1 : NSObject
+-(void)use_method_warn;
+@end
+
+@implementation Test1
+-(void)use_method_warn {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100);
+}
+@end
+
+
+// No warnings: class name contains "mock"
+@interface Mock1 : NSObject
+-(void)use_method_warn;
+@end
+
+@implementation Mock1
+-(void)use_method_warn {
+ dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+
+ func(^{
+ dispatch_semaphore_signal(sema);
+ });
+ dispatch_semaphore_wait(sema, 100);
+}
+@end
Index: lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
+++ lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
@@ -0,0 +1,166 @@
+//===- GCDAntipatternChecker.cpp ---------------------------------*- C++ -*-==//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines GCDAntipatternChecker which checks against a common
+// antipattern when synchronous API is emulated from asynchronous callbacks
+// using a semaphore:
+//
+// dispatch_semaphore_t sema = dispatch_semaphore_create(0);
+//
+// AnyCFunctionCall(^{
+// // code…
+// dispatch_semaphore_signal(sema);
+// })
+// dispatch_semaphore_wait(sema, *)
+//
+// Such code is a common performance problem, due to inability of GCD to
+// properly handle QoS when a combination of queues and semaphores is used.
+// Good code would either use asynchronous API (when available), or perform
+// the necessary action in asynchronous callback.
+//
+// Currently, the check is performed using a simple heuristical AST pattern
+// matching.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
+#include "llvm/Support/Debug.h"
+
+using namespace clang;
+using namespace ento;
+using namespace ast_matchers;
+
+namespace {
+
+const char *WarningBinding = "semaphore_wait";
+
+class GCDAntipatternChecker : public Checker<check::ASTCodeBody> {
+public:
+ void checkASTCodeBody(const Decl *D,
+ AnalysisManager &AM,
+ BugReporter &BR) const;
+};
+
+class Callback : public MatchFinder::MatchCallback {
+ BugReporter &BR;
+ const GCDAntipatternChecker *C;
+ AnalysisDeclContext *ADC;
+
+public:
+ Callback(BugReporter &BR,
+ AnalysisDeclContext *ADC,
+ const GCDAntipatternChecker *C) : BR(BR), C(C), ADC(ADC) {}
+
+ virtual void run(const MatchFinder::MatchResult &Result) override;
+};
+
+auto callsName(const char *FunctionName)
+ -> decltype(callee(functionDecl())) {
+ return callee(functionDecl(hasName(FunctionName)));
+}
+
+auto equalsBoundArgDecl(int ArgIdx, const char *DeclName)
+ -> decltype(hasArgument(0, expr())) {
+ return hasArgument(ArgIdx, ignoringParenCasts(declRefExpr(
+ to(varDecl(equalsBoundNode(DeclName))))));
+}
+
+auto bindAssignmentToDecl(const char *DeclName) -> decltype(hasLHS(expr())) {
+ return hasLHS(ignoringParenImpCasts(
+ declRefExpr(to(varDecl().bind(DeclName)))));
+}
+
+void GCDAntipatternChecker::checkASTCodeBody(const Decl *D,
+ AnalysisManager &AM,
+ BugReporter &BR) const {
+
+ // The pattern is very common in tests, and it is OK to use it there.
+ if (const auto* ND = dyn_cast<NamedDecl>(D)) {
+ std::string DeclName = ND->getNameAsString();
+ if (StringRef(DeclName).startswith("test"))
+ return;
+ }
+ if (const auto *OD = dyn_cast<ObjCMethodDecl>(D)) {
+ if (const auto *CD = dyn_cast<ObjCContainerDecl>(OD->getParent())) {
+ std::string ContainerName = CD->getNameAsString();
+ StringRef CN(ContainerName);
+ if (CN.contains_lower("test") || CN.contains_lower("mock"))
+ return;
+ }
+ }
+
+ const char *SemaphoreBinding = "semaphore_name";
+ auto SemaphoreCreateM = callExpr(callsName("dispatch_semaphore_create"));
+
+ auto SemaphoreBindingM = anyOf(
+ forEachDescendant(
+ varDecl(hasDescendant(SemaphoreCreateM)).bind(SemaphoreBinding)),
+ forEachDescendant(binaryOperator(bindAssignmentToDecl(SemaphoreBinding),
+ hasRHS(SemaphoreCreateM))));
+
+ auto SemaphoreWaitM = forEachDescendant(
+ callExpr(
+ allOf(
+ callsName("dispatch_semaphore_wait"),
+ equalsBoundArgDecl(0, SemaphoreBinding)
+ )
+ ).bind(WarningBinding));
+
+ auto HasBlockArgumentM = hasAnyArgument(hasType(
+ hasCanonicalType(blockPointerType())
+ ));
+
+ auto ArgCallsSignalM = hasArgument(0, hasDescendant(callExpr(
+ allOf(
+ callsName("dispatch_semaphore_signal"),
+ equalsBoundArgDecl(0, SemaphoreBinding)
+ ))));
+
+ auto HasBlockAndCallsSignalM = allOf(HasBlockArgumentM, ArgCallsSignalM);
+
+ auto AcceptsBlockM =
+ forEachDescendant(
+ stmt(anyOf(
+ callExpr(HasBlockAndCallsSignalM),
+ objcMessageExpr(HasBlockAndCallsSignalM)
+ )));
+
+ auto FinalM = compoundStmt(SemaphoreBindingM, SemaphoreWaitM, AcceptsBlockM);
+
+ MatchFinder F;
+ Callback CB(BR, AM.getAnalysisDeclContext(D), this);
+
+ F.addMatcher(FinalM, &CB);
+ F.match(*D->getBody(), AM.getASTContext());
+}
+
+void Callback::run(const MatchFinder::MatchResult &Result) {
+ const auto *SW = Result.Nodes.getNodeAs<CallExpr>(WarningBinding);
+ assert(SW);
+ BR.EmitBasicReport(
+ ADC->getDecl(), C,
+ /*Name=*/"Semaphore performance anti-pattern",
+ /*Category=*/"Performance",
+ "Waiting on a semaphore with Grand Central Dispatch creates useless "
+ "threads and is subject to priority inversion; consider "
+ "using a synchronous API or changing the caller to be asynchronous",
+ PathDiagnosticLocation::createBegin(SW, BR.getSourceManager(), ADC),
+ SW->getSourceRange());
+}
+
+}
+
+void ento::registerGCDAntipattern(CheckerManager &Mgr) {
+ Mgr.registerChecker<GCDAntipatternChecker>();
+}
Index: lib/StaticAnalyzer/Checkers/CMakeLists.txt
===================================================================
--- lib/StaticAnalyzer/Checkers/CMakeLists.txt
+++ lib/StaticAnalyzer/Checkers/CMakeLists.txt
@@ -37,7 +37,7 @@
DynamicTypeChecker.cpp
ExprInspectionChecker.cpp
FixedAddressChecker.cpp
- GCDAsyncSemaphoreChecker.cpp
+ GCDAntipatternChecker.cpp
GenericTaintChecker.cpp
GTestChecker.cpp
IdenticalExprChecker.cpp
Index: test/Analysis/gcdasyncsemaphorechecker_test.m
===================================================================
--- test/Analysis/gcdasyncsemaphorechecker_test.m
+++ test/Analysis/gcdasyncsemaphorechecker_test.m
@@ -1,234 +0,0 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,alpha.osx.GCDAsyncSemaphore %s -fblocks -verify
-typedef signed char BOOL;
-@protocol NSObject - (BOOL)isEqual:(id)object; @end
-@interface NSObject <NSObject> {}
-+(id)alloc;
--(id)init;
--(id)autorelease;
--(id)copy;
--(id)retain;
-@end
-
-typedef int dispatch_semaphore_t;
-typedef void (^block_t)();
-
-dispatch_semaphore_t dispatch_semaphore_create(int);
-void dispatch_semaphore_wait(dispatch_semaphore_t, int);
-void dispatch_semaphore_signal(dispatch_semaphore_t);
-
-void func(void (^)(void));
-void func_w_typedef(block_t);
-
-int coin();
-
-void use_semaphor_antipattern() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-// It's OK to use pattern in tests.
-// We simply match the containing function name against ^test.
-void test_no_warning() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100);
-}
-
-void use_semaphor_antipattern_multiple_times() {
- dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema1);
- });
- dispatch_semaphore_wait(sema1, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-
- dispatch_semaphore_t sema2 = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema2);
- });
- dispatch_semaphore_wait(sema2, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void use_semaphor_antipattern_multiple_wait() {
- dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema1);
- });
- // FIXME: multiple waits on same semaphor should not raise a warning.
- dispatch_semaphore_wait(sema1, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
- dispatch_semaphore_wait(sema1, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void warn_incorrect_order() {
- // FIXME: ASTMatchers do not allow ordered matching, so would match even
- // if out of order.
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
- func(^{
- dispatch_semaphore_signal(sema);
- });
-}
-
-void warn_w_typedef() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func_w_typedef(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void warn_nested_ast() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- if (coin()) {
- func(^{
- dispatch_semaphore_signal(sema);
- });
- } else {
- func(^{
- dispatch_semaphore_signal(sema);
- });
- }
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void use_semaphore_assignment() {
- dispatch_semaphore_t sema;
- sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void use_semaphore_assignment_init() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
- sema = dispatch_semaphore_create(1);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void differentsemaphoreok() {
- dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
- dispatch_semaphore_t sema2 = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema1);
- });
- dispatch_semaphore_wait(sema2, 100); // no-warning
-}
-
-void nosignalok() {
- dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
- dispatch_semaphore_wait(sema1, 100);
-}
-
-void nowaitok() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
- func(^{
- dispatch_semaphore_signal(sema);
- });
-}
-
-void noblockok() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
- dispatch_semaphore_signal(sema);
- dispatch_semaphore_wait(sema, 100);
-}
-
-void storedblockok() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
- block_t b = ^{
- dispatch_semaphore_signal(sema);
- };
- dispatch_semaphore_wait(sema, 100);
-}
-
-void passed_semaphore_ok(dispatch_semaphore_t sema) {
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100);
-}
-
-void warn_with_cast() {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal((int)sema);
- });
- dispatch_semaphore_wait((int)sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-@interface Test1 : NSObject
--(void)use_method_warn;
--(void)use_objc_callback_warn;
--(void)testNoWarn;
--(void)acceptBlock:(block_t)callback;
-@end
-
-@implementation Test1
-
--(void)use_method_warn {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
--(void)testNoWarn {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100);
-}
-
--(void)acceptBlock:(block_t) callback {
- callback();
-}
-
--(void)use_objc_callback_warn {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- [self acceptBlock:^{
- dispatch_semaphore_signal(sema);
- }];
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-void use_objc_and_c_callback(Test1 *t) {
- dispatch_semaphore_t sema = dispatch_semaphore_create(0);
-
- func(^{
- dispatch_semaphore_signal(sema);
- });
- dispatch_semaphore_wait(sema, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-
- dispatch_semaphore_t sema1 = dispatch_semaphore_create(0);
-
- [t acceptBlock:^{
- dispatch_semaphore_signal(sema1);
- }];
- dispatch_semaphore_wait(sema1, 100); // expected-warning{{Possible semaphore performance anti-pattern}}
-}
-
-@end
Index: lib/StaticAnalyzer/Checkers/GCDAsyncSemaphoreChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/GCDAsyncSemaphoreChecker.cpp
+++ lib/StaticAnalyzer/Checkers/GCDAsyncSemaphoreChecker.cpp
@@ -1,159 +0,0 @@
-//===- GCDAsyncSemaphoreChecker.cpp -----------------------------*- C++ -*-==//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file defines GCDAsyncSemaphoreChecker which checks against a common
-// antipattern when synchronous API is emulated from asynchronous callbacks
-// using a semaphor:
-//
-// dispatch_semapshore_t sema = dispatch_semaphore_create(0);
-
-// AnyCFunctionCall(^{
-// // code…
-// dispatch_semapshore_signal(sema);
-// })
-// dispatch_semapshore_wait(sema, *)
-//
-// Such code is a common performance problem, due to inability of GCD to
-// properly handle QoS when a combination of queues and semaphors is used.
-// Good code would either use asynchronous API (when available), or perform
-// the necessary action in asynchronous callback.
-//
-// Currently, the check is performed using a simple heuristical AST pattern
-// matching.
-//
-//===----------------------------------------------------------------------===//
-
-#include "ClangSACheckers.h"
-#include "clang/ASTMatchers/ASTMatchFinder.h"
-#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
-#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
-#include "clang/StaticAnalyzer/Core/Checker.h"
-#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
-#include "llvm/Support/Debug.h"
-
-#define DEBUG_TYPE "gcdasyncsemaphorechecker"
-
-using namespace clang;
-using namespace ento;
-using namespace ast_matchers;
-
-namespace {
-
-const char *WarningBinding = "semaphore_wait";
-
-class GCDAsyncSemaphoreChecker : public Checker<check::ASTCodeBody> {
-public:
- void checkASTCodeBody(const Decl *D,
- AnalysisManager &AM,
- BugReporter &BR) const;
-};
-
-class Callback : public MatchFinder::MatchCallback {
- BugReporter &BR;
- const GCDAsyncSemaphoreChecker *C;
- AnalysisDeclContext *ADC;
-
-public:
- Callback(BugReporter &BR,
- AnalysisDeclContext *ADC,
- const GCDAsyncSemaphoreChecker *C) : BR(BR), C(C), ADC(ADC) {}
-
- virtual void run(const MatchFinder::MatchResult &Result) override;
-};
-
-auto callsName(const char *FunctionName)
- -> decltype(callee(functionDecl())) {
- return callee(functionDecl(hasName(FunctionName)));
-}
-
-auto equalsBoundArgDecl(int ArgIdx, const char *DeclName)
- -> decltype(hasArgument(0, expr())) {
- return hasArgument(ArgIdx, ignoringParenCasts(declRefExpr(
- to(varDecl(equalsBoundNode(DeclName))))));
-}
-
-auto bindAssignmentToDecl(const char *DeclName) -> decltype(hasLHS(expr())) {
- return hasLHS(ignoringParenImpCasts(
- declRefExpr(to(varDecl().bind(DeclName)))));
-}
-
-void GCDAsyncSemaphoreChecker::checkASTCodeBody(const Decl *D,
- AnalysisManager &AM,
- BugReporter &BR) const {
-
- // The pattern is very common in tests, and it is OK to use it there.
- if (const auto* ND = dyn_cast<NamedDecl>(D)) {
- std::string DeclName = ND->getNameAsString();
- if (StringRef(DeclName).startswith("test"))
- return;
- }
-
- const char *SemaphoreBinding = "semaphore_name";
- auto SemaphoreCreateM = callExpr(callsName("dispatch_semaphore_create"));
-
- auto SemaphoreBindingM = anyOf(
- forEachDescendant(
- varDecl(hasDescendant(SemaphoreCreateM)).bind(SemaphoreBinding)),
- forEachDescendant(binaryOperator(bindAssignmentToDecl(SemaphoreBinding),
- hasRHS(SemaphoreCreateM))));
-
- auto SemaphoreWaitM = forEachDescendant(
- callExpr(
- allOf(
- callsName("dispatch_semaphore_wait"),
- equalsBoundArgDecl(0, SemaphoreBinding)
- )
- ).bind(WarningBinding));
-
- auto HasBlockArgumentM = hasAnyArgument(hasType(
- hasCanonicalType(blockPointerType())
- ));
-
- auto ArgCallsSignalM = hasArgument(0, hasDescendant(callExpr(
- allOf(
- callsName("dispatch_semaphore_signal"),
- equalsBoundArgDecl(0, SemaphoreBinding)
- ))));
-
- auto HasBlockAndCallsSignalM = allOf(HasBlockArgumentM, ArgCallsSignalM);
-
- auto AcceptsBlockM =
- forEachDescendant(
- stmt(anyOf(
- callExpr(HasBlockAndCallsSignalM),
- objcMessageExpr(HasBlockAndCallsSignalM)
- )));
-
- auto FinalM = compoundStmt(SemaphoreBindingM, SemaphoreWaitM, AcceptsBlockM);
-
- MatchFinder F;
- Callback CB(BR, AM.getAnalysisDeclContext(D), this);
-
- F.addMatcher(FinalM, &CB);
- F.match(*D->getBody(), AM.getASTContext());
-}
-
-void Callback::run(const MatchFinder::MatchResult &Result) {
- const auto *SW = Result.Nodes.getNodeAs<CallExpr>(WarningBinding);
- assert(SW);
- BR.EmitBasicReport(
- ADC->getDecl(), C,
- /*Name=*/"Semaphore performance anti-pattern",
- /*Category=*/"Performance",
- "Possible semaphore performance anti-pattern: wait on a semaphore "
- "signalled to in a callback",
- PathDiagnosticLocation::createBegin(SW, BR.getSourceManager(), ADC),
- SW->getSourceRange());
-}
-
-}
-
-void ento::registerGCDAsyncSemaphoreChecker(CheckerManager &Mgr) {
- Mgr.registerChecker<GCDAsyncSemaphoreChecker>();
-}
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