[analyzer] [NFC] Split up summary generation in RetainCountChecker in two methods

[george.karpenkov]

Summary

... clang-tidy check for do ... while(0) anyone? :P

[NoQ]

Ah, finally someone tried to figure out if S is ever overwritten here.

... clang-tidy check for do ... while(0) anyone? :P

People often write do ... while(0); when they are ashamed to write goto fail;. I suspect that it'd be pretty hard for path-insensitive analysis to figure out that we could actually replace breaks with returns here.

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.h

502

I like it how this dude became private as well.

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.h

public:
 
   void updateSummaryForCall(const RetainSummary *&Summ,
                             const CallEvent &Call);
 
   bool isARCEnabled() const { return ARCEnabled; }
 
   RetEffect getObjAllocRetEffect() const { return ObjCAllocRetE; }
 
+private:
+  const RetainSummary * generateSummary(const FunctionDecl *FD,
+                                        bool &AllowAnnotations);
+
   friend class RetainSummaryTemplate;
 };
 
 // Used to avoid allocating long-term (BPAlloc'd) memory for default retain
 // summaries. If a function or method looks like it has a default summary, but
 // it has annotations, the annotations are added to the stack-based template
 // and then copied into managed memory.
 class RetainSummaryTemplate {
   RetainSummaryManager &Manager;

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountSummaries.cpp

RetainSummaryManager::getPersistentSummary(const RetainSummary &OldSumm) {
   }
 
   RetainSummary *Summ = (RetainSummary *) BPAlloc.Allocate<RetainSummary>();
   new (Summ) RetainSummary(OldSumm);
   return Summ;
 }
 
 const RetainSummary *
-RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
-  // If we don't know what function we're calling, use our default summary.
-  if (!FD)
-    return getDefaultSummary();
-
-  // Look up a summary in our cache of FunctionDecls -> Summaries.
-  FuncSummariesTy::iterator I = FuncSummaries.find(FD);
-  if (I != FuncSummaries.end())
-    return I->second;
-
-  // No summary?  Generate one.
-  const RetainSummary *S = nullptr;
-  bool AllowAnnotations = true;
-
-  do {
-    // We generate "stop" summaries for implicitly defined functions.
-    if (FD->isImplicit()) {
-      S = getPersistentStopSummary();
-      break;
-    }
+RetainSummaryManager::generateSummary(const FunctionDecl *FD,
+                                      bool &AllowAnnotations) {
+    return getPersistentStopSummary();
 
-    // [PR 3337] Use 'getAs<FunctionType>' to strip away any typedefs on the
-    // function's type.
-    const FunctionType* FT = FD->getType()->getAs<FunctionType>();
-    const IdentifierInfo *II = FD->getIdentifier();
-    if (!II)
-      break;
+  const FunctionType *FT = FD->getType()->getAs<FunctionType>();
+    return getDefaultSummary();
 
-    StringRef FName = II->getName();
 
-    // Strip away preceding '_'.  Doing this here will effect all the checks
-    // down below.
-    FName = FName.substr(FName.find_first_not_of('_'));
 
-    // Inspect the result type.
-    QualType RetTy = FT->getReturnType();
-    std::string RetTyName = RetTy.getAsString();
 
-    // FIXME: This should all be refactored into a chain of "summary lookup"
-    //  filters.
-    assert(ScratchArgs.isEmpty());
 
-    if (FName == "pthread_create" || FName == "pthread_setspecific") {
-      // Part of: <rdar://problem/7299394> and <rdar://problem/11282706>.
-      // This will be addressed better with IPA.
-      S = getPersistentStopSummary();
-    } else if (FName == "CFPlugInInstanceCreate") {
-      S = getPersistentSummary(RetEffect::MakeNoRet());
-    } else if (FName == "IORegistryEntrySearchCFProperty"
-        || (RetTyName == "CFMutableDictionaryRef" && (
-               FName == "IOBSDNameMatching" ||
-               FName == "IOServiceMatching" ||
+    return getPersistentStopSummary();
+    return getPersistentSummary(RetEffect::MakeNoRet());
+  } else if (FName == "IORegistryEntrySearchCFProperty" ||
+             (RetTyName == "CFMutableDictionaryRef" &&
+              (FName == "IOBSDNameMatching" || FName == "IOServiceMatching" ||
                FName == "IOServiceNameMatching" ||
                FName == "IORegistryEntryIDMatching" ||
-               FName == "IOOpenFirmwarePathMatching"
-            ))) {
-      // Part of <rdar://problem/6961230>. (IOKit)
-      // This should be addressed using a API table.
-      S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
-                               DoNothing, DoNothing);
-    } else if (FName == "IOServiceGetMatchingService" ||
-               FName == "IOServiceGetMatchingServices") {
-      // FIXES: <rdar://problem/6326900>
-      // This should be addressed using a API table.  This strcmp is also
-      // a little gross, but there is no need to super optimize here.
-      ScratchArgs = AF.add(ScratchArgs, 1, DecRef);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName == "IOServiceAddNotification" ||
-               FName == "IOServiceAddMatchingNotification") {
-      // Part of <rdar://problem/6961230>. (IOKit)
-      // This should be addressed using a API table.
-      ScratchArgs = AF.add(ScratchArgs, 2, DecRef);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName == "CVPixelBufferCreateWithBytes") {
-      // FIXES: <rdar://problem/7283567>
-      // Eventually this can be improved by recognizing that the pixel
-      // buffer passed to CVPixelBufferCreateWithBytes is released via
-      // a callback and doing full IPA to make sure this is done correctly.
-      // FIXME: This function has an out parameter that returns an
-      // allocated object.
-      ScratchArgs = AF.add(ScratchArgs, 7, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName == "CGBitmapContextCreateWithData") {
-      // FIXES: <rdar://problem/7358899>
-      // Eventually this can be improved by recognizing that 'releaseInfo'
-      // passed to CGBitmapContextCreateWithData is released via
-      // a callback and doing full IPA to make sure this is done correctly.
-      ScratchArgs = AF.add(ScratchArgs, 8, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF),
-                               DoNothing, DoNothing);
-    } else if (FName == "CVPixelBufferCreateWithPlanarBytes") {
-      // FIXES: <rdar://problem/7283567>
-      // Eventually this can be improved by recognizing that the pixel
-      // buffer passed to CVPixelBufferCreateWithPlanarBytes is released
-      // via a callback and doing full IPA to make sure this is done
-      // correctly.
-      ScratchArgs = AF.add(ScratchArgs, 12, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName == "VTCompressionSessionEncodeFrame") {
-      // The context argument passed to VTCompressionSessionEncodeFrame()
-      // is passed to the callback specified when creating the session
-      // (e.g. with VTCompressionSessionCreate()) which can release it.
-      // To account for this possibility, conservatively stop tracking
-      // the context.
-      ScratchArgs = AF.add(ScratchArgs, 5, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName == "dispatch_set_context" ||
-               FName == "xpc_connection_set_context") {
-      // <rdar://problem/11059275> - The analyzer currently doesn't have
-      // a good way to reason about the finalizer function for libdispatch.
-      // If we pass a context object that is memory managed, stop tracking it.
-      // <rdar://problem/13783514> - Same problem, but for XPC.
-      // FIXME: this hack should possibly go away once we can handle
-      // libdispatch and XPC finalizers.
-      ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    } else if (FName.startswith("NSLog")) {
-      S = getDoNothingSummary();
-    } else if (FName.startswith("NS") &&
-                (FName.find("Insert") != StringRef::npos)) {
-      // Whitelist NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
-      // be deallocated by NSMapRemove. (radar://11152419)
-      ScratchArgs = AF.add(ScratchArgs, 1, StopTracking);
-      ScratchArgs = AF.add(ScratchArgs, 2, StopTracking);
-      S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
-    }
+               FName == "IOOpenFirmwarePathMatching"))) {
+    return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF), DoNothing,
+                             DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getPersistentSummary(RetEffect::MakeOwned(RetEffect::CF), DoNothing,
+                             DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
+    return getDoNothingSummary();
+    return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, DoNothing);
 
-    // Did we get a summary?
-    if (S)
-      break;
-
-    if (RetTy->isPointerType()) {
-      // For CoreFoundation ('CF') types.
-      if (cocoa::isRefType(RetTy, "CF", FName)) {
-        if (RetainSummary::isRetain(FD, FName)) {
-          S = getUnarySummary(FT, cfretain);
-          // CFRetain isn't supposed to be annotated. However, this may as well
-          // be a user-made "safe" CFRetain function that is incorrectly
-          // annotated as cf_returns_retained due to lack of better options.
-          // We want to ignore such annotation.
-          AllowAnnotations = false;
-        } else if (RetainSummary::isAutorelease(FD, FName)) {
-          S = getUnarySummary(FT, cfautorelease);
-          // The headers use cf_consumed, but we can fully model CFAutorelease
-          // ourselves.
-          AllowAnnotations = false;
-        } else {
-          S = getCFCreateGetRuleSummary(FD);
-        }
-
-        break;
-      }
+
+        return getUnarySummary(FT, cfretain);
+
+        return getUnarySummary(FT, cfautorelease);
+        return getCFCreateGetRuleSummary(FD);
 
-      // For CoreGraphics ('CG') and CoreVideo ('CV') types.
-      if (cocoa::isRefType(RetTy, "CG", FName) ||
-          cocoa::isRefType(RetTy, "CV", FName)) {
-        if (RetainSummary::isRetain(FD, FName))
-          S = getUnarySummary(FT, cfretain);
-        else
-          S = getCFCreateGetRuleSummary(FD);
-
-        break;
-      }
+        return getUnarySummary(FT, cfretain);
+        return getCFCreateGetRuleSummary(FD);
 
-      // For all other CF-style types, use the Create/Get
-      // rule for summaries but don't support Retain functions
-      // with framework-specific prefixes.
-      if (coreFoundation::isCFObjectRef(RetTy)) {
-        S = getCFCreateGetRuleSummary(FD);
-        break;
-      }
+      return getCFCreateGetRuleSummary(FD);
 
-      if (FD->hasAttr<CFAuditedTransferAttr>()) {
-        S = getCFCreateGetRuleSummary(FD);
-        break;
-      }
-
-      break;
-    }
+      return getCFCreateGetRuleSummary(FD);
 
-    // Check for release functions, the only kind of functions that we care
-    // about that don't return a pointer type.
-    if (FName.size() >= 2 &&
-        FName[0] == 'C' && (FName[1] == 'F' || FName[1] == 'G')) {
-      // Test for 'CGCF'.
-      FName = FName.substr(FName.startswith("CGCF") ? 4 : 2);
+  if (FName.size() >= 2 && FName[0] == 'C' &&
+      (FName[1] == 'F' || FName[1] == 'G')) {
 
-      if (RetainSummary::isRelease(FD, FName))
-        S = getUnarySummary(FT, cfrelease);
-      else {
-        assert (ScratchArgs.isEmpty());
-        // Remaining CoreFoundation and CoreGraphics functions.
-        // We use to assume that they all strictly followed the ownership idiom
-        // and that ownership cannot be transferred.  While this is technically
-        // correct, many methods allow a tracked object to escape.  For example:
-        //
-        //   CFMutableDictionaryRef x = CFDictionaryCreateMutable(...);
-        //   CFDictionaryAddValue(y, key, x);
-        //   CFRelease(x);
-        //   ... it is okay to use 'x' since 'y' has a reference to it
-        //
-        // We handle this and similar cases with the follow heuristic.  If the
-        // function name contains "InsertValue", "SetValue", "AddValue",
-        // "AppendValue", or "SetAttribute", then we assume that arguments may
-        // "escape."  This means that something else holds on to the object,
-        // allowing it be used even after its local retain count drops to 0.
-        ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos||
-                       StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
-                       StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
-                       StrInStrNoCase(FName, "AppendValue") != StringRef::npos||
-                       StrInStrNoCase(FName, "SetAttribute") != StringRef::npos)
-                      ? MayEscape : DoNothing;
+      return getUnarySummary(FT, cfrelease);
+      assert(ScratchArgs.isEmpty());
+      ArgEffect E = (StrInStrNoCase(FName, "InsertValue") != StringRef::npos ||
+                     StrInStrNoCase(FName, "AppendValue") != StringRef::npos ||
+                        ? MayEscape
+                        : DoNothing;
 
-        S = getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E);
-      }
-    }
-  }
-  while (0);
+      return getPersistentSummary(RetEffect::MakeNoRet(), DoNothing, E);
+
+  return getDefaultSummary();
 
-  // If we got all the way here without any luck, use a default summary.
-  if (!S)
-    S = getDefaultSummary();
+const RetainSummary *
+RetainSummaryManager::getFunctionSummary(const FunctionDecl *FD) {
+  // If we don't know what function we're calling, use our default summary.
+  if (!FD)
+    return getDefaultSummary();
+
+  // Look up a summary in our cache of FunctionDecls -> Summaries.
+  FuncSummariesTy::iterator I = FuncSummaries.find(FD);
+  if (I != FuncSummaries.end())
+    return I->second;
+
+  // No summary?  Generate one.
+  bool AllowAnnotations = true;
+  const RetainSummary *S = generateSummary(FD, AllowAnnotations);
 
   // Annotations override defaults.
   if (AllowAnnotations)
     updateSummaryFromAnnotations(S, FD);
 
   FuncSummaries[FD] = S;
   return S;
 }