Merge branch 'main' into issue_161335

Author: RKSimon

bolt/lib/Profile/DataAggregator.cpp

@@ -564,30 +564,30 @@ void DataAggregator::imputeFallThroughs() {
     // Skip fall-throughs in external code.
     if (Trace.From == Trace::EXTERNAL)
       continue;
-    std::pair CurrentBranch(Trace.Branch, Trace.From);
+    if (std::pair CurrentBranch(Trace.Branch, Trace.From);
+        CurrentBranch != PrevBranch) {
+      // New group: reset aggregates.
+      AggregateCount = AggregateFallthroughSize = 0;
+      PrevBranch = CurrentBranch;
+    }
     // BR_ONLY must be the last trace in the group
     if (Trace.To == Trace::BR_ONLY) {
       // If the group is not empty, use aggregate values, otherwise 0-length
       // for unconditional jumps (call/ret/uncond branch) or 1-length for others
       uint64_t InferredBytes =
-          PrevBranch == CurrentBranch
+          AggregateFallthroughSize
               ? AggregateFallthroughSize / AggregateCount
               : !checkUnconditionalControlTransfer(Trace.From);
       Trace.To = Trace.From + InferredBytes;
       LLVM_DEBUG(dbgs() << "imputed " << Trace << " (" << InferredBytes
                         << " bytes)\n");
       ++InferredTraces;
     } else {
-      // Trace with a valid fall-through
-      // New group: reset aggregates.
-      if (CurrentBranch != PrevBranch)
-        AggregateCount = AggregateFallthroughSize = 0;
       // Only use valid fall-through lengths
       if (Trace.To != Trace::EXTERNAL)
         AggregateFallthroughSize += (Trace.To - Trace.From) * Info.TakenCount;
       AggregateCount += Info.TakenCount;
     }
-    PrevBranch = CurrentBranch;
   }
   if (opts::Verbosity >= 1)
     outs() << "BOLT-INFO: imputed " << InferredTraces << " traces\n";

bolt/test/X86/callcont-fallthru.s

@@ -15,6 +15,8 @@
 # External return to a landing pad/entry point call continuation
 # RUN: link_fdata %s %t %t.pa-eret PREAGG-ERET
 # RUN-DISABLED: link_fdata %s %t %t.pa-plt PREAGG-PLT
+## Fall-through imputing test cases
+# RUN: link_fdata %s %t %t.pa-imp PREAGG-IMP
 
 # RUN: llvm-strip --strip-unneeded %t -o %t.strip
 # RUN: llvm-objcopy --remove-section=.eh_frame %t.strip %t.noeh
@@ -63,6 +65,11 @@
 # RUN-DISABLED:   --check-prefix=CHECK-PLT
 # CHECK-PLT: traces mismatching disassembled function contents: 0
 
+## Check --impute-trace-fall-throughs accepting duplicate branch-only traces
+# RUN: perf2bolt %t --pa -p %t.pa-imp -o %t.pa-imp.fdata --impute-trace-fall-through
+# RUN: FileCheck %s --check-prefix=CHECK-IMP --input-file %t.pa-imp.fdata
+# CHECK-IMP: 0 [unknown] 0 1 main {{.*}} 0 3
+
   .globl foo
   .type foo, %function
 foo:
@@ -102,6 +109,8 @@ Ltmp1:
 
 Ltmp4:
 	cmpl	$0x0, -0x14(%rbp)
+# PREAGG-IMP: B X:0 #Ltmp4_br# 1 0
+# PREAGG-IMP: B X:0 #Ltmp4_br# 2 0
 Ltmp4_br:
 	je	Ltmp0
 

clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp

@@ -73,6 +73,7 @@
 #include "SizeofExpressionCheck.h"
 #include "SpuriouslyWakeUpFunctionsCheck.h"
 #include "StandaloneEmptyCheck.h"
+#include "StdNamespaceModificationCheck.h"
 #include "StringConstructorCheck.h"
 #include "StringIntegerAssignmentCheck.h"
 #include "StringLiteralWithEmbeddedNulCheck.h"
@@ -237,6 +238,8 @@ class BugproneModule : public ClangTidyModule {
         "bugprone-spuriously-wake-up-functions");
     CheckFactories.registerCheck<StandaloneEmptyCheck>(
         "bugprone-standalone-empty");
+    CheckFactories.registerCheck<StdNamespaceModificationCheck>(
+        "bugprone-std-namespace-modification");
     CheckFactories.registerCheck<StringConstructorCheck>(
         "bugprone-string-constructor");
     CheckFactories.registerCheck<StringIntegerAssignmentCheck>(

clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt

@@ -75,6 +75,7 @@ add_clang_library(clangTidyBugproneModule STATIC
   SmartPtrArrayMismatchCheck.cpp
   SpuriouslyWakeUpFunctionsCheck.cpp
   StandaloneEmptyCheck.cpp
+  StdNamespaceModificationCheck.cpp
   StringConstructorCheck.cpp
   StringIntegerAssignmentCheck.cpp
   StringLiteralWithEmbeddedNulCheck.cpp

clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp renamed to clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DontModifyStdNamespaceCheck.h"
+#include "StdNamespaceModificationCheck.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchersInternal.h"
 
@@ -36,9 +36,9 @@ AST_POLYMORPHIC_MATCHER_P(
 
 } // namespace
 
-namespace clang::tidy::cert {
+namespace clang::tidy::bugprone {
 
-void DontModifyStdNamespaceCheck::registerMatchers(MatchFinder *Finder) {
+void StdNamespaceModificationCheck::registerMatchers(MatchFinder *Finder) {
   auto HasStdParent =
       hasDeclContext(namespaceDecl(hasAnyName("std", "posix"),
                                    unless(hasParent(namespaceDecl())))
@@ -96,7 +96,7 @@ void DontModifyStdNamespaceCheck::registerMatchers(MatchFinder *Finder) {
                          .bind("decl"),
                      this);
 }
-} // namespace clang::tidy::cert
+} // namespace clang::tidy::bugprone
 
 static const NamespaceDecl *getTopLevelLexicalNamespaceDecl(const Decl *D) {
   const NamespaceDecl *LastNS = nullptr;
@@ -108,7 +108,7 @@ static const NamespaceDecl *getTopLevelLexicalNamespaceDecl(const Decl *D) {
   return LastNS;
 }
 
-void clang::tidy::cert::DontModifyStdNamespaceCheck::check(
+void clang::tidy::bugprone::StdNamespaceModificationCheck::check(
     const MatchFinder::MatchResult &Result) {
   const auto *D = Result.Nodes.getNodeAs<Decl>("decl");
   const auto *NS = Result.Nodes.getNodeAs<NamespaceDecl>("nmspc");

clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.h renamed to clang-tools-extra/clang-tidy/bugprone/StdNamespaceModificationCheck.h

@@ -6,21 +6,21 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DONT_MODIFY_STD_NAMESPACE_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DONT_MODIFY_STD_NAMESPACE_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STDNAMESPACEMODIFICATIONCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STDNAMESPACEMODIFICATIONCHECK_H
 
 #include "../ClangTidyCheck.h"
 
-namespace clang::tidy::cert {
+namespace clang::tidy::bugprone {
 
 /// Modification of the std or posix namespace can result in undefined behavior.
 /// This check warns for such modifications.
 ///
 /// For the user-facing documentation see:
-/// https://clang.llvm.org/extra/clang-tidy/checks/cert/dcl58-cpp.html
-class DontModifyStdNamespaceCheck : public ClangTidyCheck {
+/// https://clang.llvm.org/extra/clang-tidy/checks/bugprone/std-namespace-modification.html
+class StdNamespaceModificationCheck : public ClangTidyCheck {
 public:
-  DontModifyStdNamespaceCheck(StringRef Name, ClangTidyContext *Context)
+  StdNamespaceModificationCheck(StringRef Name, ClangTidyContext *Context)
       : ClangTidyCheck(Name, Context) {}
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus;
@@ -29,6 +29,6 @@ class DontModifyStdNamespaceCheck : public ClangTidyCheck {
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 };
 
-} // namespace clang::tidy::cert
+} // namespace clang::tidy::bugprone
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_DONT_MODIFY_STD_NAMESPACE_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_STDNAMESPACEMODIFICATIONCHECK_H

clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp

@@ -19,6 +19,7 @@
 #include "../bugprone/SignedCharMisuseCheck.h"
 #include "../bugprone/SizeofExpressionCheck.h"
 #include "../bugprone/SpuriouslyWakeUpFunctionsCheck.h"
+#include "../bugprone/StdNamespaceModificationCheck.h"
 #include "../bugprone/SuspiciousMemoryComparisonCheck.h"
 #include "../bugprone/ThrowingStaticInitializationCheck.h"
 #include "../bugprone/UncheckedStringToNumberConversionCheck.h"
@@ -36,7 +37,6 @@
 #include "../performance/MoveConstructorInitCheck.h"
 #include "../readability/EnumInitialValueCheck.h"
 #include "../readability/UppercaseLiteralSuffixCheck.h"
-#include "DontModifyStdNamespaceCheck.h"
 #include "FloatLoopCounter.h"
 #include "LimitedRandomnessCheck.h"
 #include "MutatingCopyCheck.h"
@@ -251,7 +251,8 @@ class CERTModule : public ClangTidyModule {
         "cert-dcl51-cpp");
     CheckFactories.registerCheck<misc::NewDeleteOverloadsCheck>(
         "cert-dcl54-cpp");
-    CheckFactories.registerCheck<DontModifyStdNamespaceCheck>("cert-dcl58-cpp");
+    CheckFactories.registerCheck<bugprone::StdNamespaceModificationCheck>(
+        "cert-dcl58-cpp");
     CheckFactories.registerCheck<google::build::UnnamedNamespaceInHeaderCheck>(
         "cert-dcl59-cpp");
     // ERR

clang-tools-extra/clang-tidy/cert/CMakeLists.txt

@@ -5,7 +5,6 @@ set(LLVM_LINK_COMPONENTS
 
 add_clang_library(clangTidyCERTModule STATIC
   CERTTidyModule.cpp
-  DontModifyStdNamespaceCheck.cpp
   FloatLoopCounter.cpp
   LimitedRandomnessCheck.cpp
   MutatingCopyCheck.cpp

clang-tools-extra/docs/ReleaseNotes.rst

@@ -244,6 +244,11 @@ New check aliases
   <clang-tidy/checks/modernize/avoid-variadic-functions>`
   keeping initial check as an alias to the new one.
 
+- Renamed :doc:`cert-dcl58-cpp <clang-tidy/checks/cert/dcl58-cpp>` to
+  :doc:`bugprone-std-namespace-modification
+  <clang-tidy/checks/bugprone/std-namespace-modification>`
+  keeping initial check as an alias to the new one.
+
 - Renamed :doc:`cert-env33-c <clang-tidy/checks/cert/env33-c>` to
   :doc:`bugprone-command-processor
   <clang-tidy/checks/bugprone/command-processor>`

clang-tools-extra/docs/clang-tidy/checks/bugprone/std-namespace-modification.rst

@@ -0,0 +1,63 @@
+.. title:: clang-tidy - bugprone-std-namespace-modification
+
+bugprone-std-namespace-modification
+===================================
+
+Warns on modifications of the ``std`` or ``posix`` namespaces which can
+result in undefined behavior.
+
+The ``std`` (or ``posix``) namespace is allowed to be extended with (class or
+function) template specializations that depend on an user-defined type (a type
+that is not defined in the standard system headers).
+
+The check detects the following (user provided) declarations in namespace ``std`` or ``posix``:
+
+- Anything that is not a template specialization.
+- Explicit specializations of any standard library function template or class template, if it does not have any user-defined type as template argument.
+- Explicit specializations of any member function of a standard library class template.
+- Explicit specializations of any member function template of a standard library class or class template.
+- Explicit or partial specialization of any member class template of a standard library class or class template.
+
+Examples:
+
+.. code-block:: c++
+
+  namespace std {
+    int x; // warning: modification of 'std' namespace can result in undefined behavior [bugprone-dont-modify-std-namespace]
+  }
+
+  namespace posix::a { // warning: modification of 'posix' namespace can result in undefined behavior
+  }
+
+  template <>
+  struct ::std::hash<long> { // warning: modification of 'std' namespace can result in undefined behavior
+    unsigned long operator()(const long &K) const {
+      return K;
+    }
+  };
+
+  struct MyData { long data; };
+
+  template <>
+  struct ::std::hash<MyData> { // no warning: specialization with user-defined type
+    unsigned long operator()(const MyData &K) const {
+      return K.data;
+    }
+  };
+
+  namespace std {
+    template <>
+    void swap<bool>(bool &a, bool &b); // warning: modification of 'std' namespace can result in undefined behavior
+
+    template <>
+    bool less<void>::operator()<MyData &&, MyData &&>(MyData &&, MyData &&) const { // warning: modification of 'std' namespace can result in undefined behavior
+      return true;
+    }
+  }
+
+References
+----------
+
+This check corresponds to the CERT C++ Coding Standard rule
+`DCL58-CPP. Do not modify the standard namespaces
+<https://www.securecoding.cert.org/confluence/display/cplusplus/DCL58-CPP.+Do+not+modify+the+standard+namespaces>`_.