LLVM and SPIRV-LLVM-Translator pulldown (WW36)

LLVM: llvm/llvm-project@83ddfa0
SPIRV-LLVM-Translator: KhronosGroup/SPIRV-LLVM-Translator@894f95b

Author: vmaksimo

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

@@ -52,6 +52,7 @@
 #include "StringLiteralWithEmbeddedNulCheck.h"
 #include "SuspiciousEnumUsageCheck.h"
 #include "SuspiciousIncludeCheck.h"
+#include "SuspiciousMemoryComparisonCheck.h"
 #include "SuspiciousMemsetUsageCheck.h"
 #include "SuspiciousMissingCommaCheck.h"
 #include "SuspiciousSemicolonCheck.h"
@@ -160,6 +161,8 @@ class BugproneModule : public ClangTidyModule {
         "bugprone-suspicious-enum-usage");
     CheckFactories.registerCheck<SuspiciousIncludeCheck>(
         "bugprone-suspicious-include");
+    CheckFactories.registerCheck<SuspiciousMemoryComparisonCheck>(
+        "bugprone-suspicious-memory-comparison");
     CheckFactories.registerCheck<SuspiciousMemsetUsageCheck>(
         "bugprone-suspicious-memset-usage");
     CheckFactories.registerCheck<SuspiciousMissingCommaCheck>(

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

@@ -47,6 +47,7 @@ add_clang_library(clangTidyBugproneModule
   StringLiteralWithEmbeddedNulCheck.cpp
   SuspiciousEnumUsageCheck.cpp
   SuspiciousIncludeCheck.cpp
+  SuspiciousMemoryComparisonCheck.cpp
   SuspiciousMemsetUsageCheck.cpp
   SuspiciousMissingCommaCheck.cpp
   SuspiciousSemicolonCheck.cpp

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

@@ -56,7 +56,7 @@ static const std::string DefaultIgnoredParameterTypeSuffixes =
                                    "reverse_const_iterator",
                                    "ConstReverseIterator",
                                    "Const_Reverse_Iterator",
-                                   "const_reverse_iterator"
+                                   "const_reverse_iterator",
                                    "Constreverseiterator",
                                    "constreverseiterator"});
 

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

@@ -0,0 +1,85 @@
+//===--- SuspiciousMemoryComparisonCheck.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 "SuspiciousMemoryComparisonCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+static llvm::Optional<uint64_t> tryEvaluateSizeExpr(const Expr *SizeExpr,
+                                                    const ASTContext &Ctx) {
+  Expr::EvalResult Result;
+  if (SizeExpr->EvaluateAsRValue(Result, Ctx))
+    return Ctx.toBits(
+        CharUnits::fromQuantity(Result.Val.getInt().getExtValue()));
+  return None;
+}
+
+void SuspiciousMemoryComparisonCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      callExpr(allOf(callee(namedDecl(
+                         anyOf(hasName("::memcmp"), hasName("::std::memcmp")))),
+                     unless(isInstantiationDependent())))
+          .bind("call"),
+      this);
+}
+
+void SuspiciousMemoryComparisonCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const ASTContext &Ctx = *Result.Context;
+  const auto *CE = Result.Nodes.getNodeAs<CallExpr>("call");
+
+  const Expr *SizeExpr = CE->getArg(2);
+  assert(SizeExpr != nullptr && "Third argument of memcmp is mandatory.");
+  llvm::Optional<uint64_t> ComparedBits = tryEvaluateSizeExpr(SizeExpr, Ctx);
+
+  for (unsigned int ArgIndex = 0; ArgIndex < 2; ++ArgIndex) {
+    const Expr *ArgExpr = CE->getArg(ArgIndex);
+    QualType ArgType = ArgExpr->IgnoreImplicit()->getType();
+    const Type *PointeeType = ArgType->getPointeeOrArrayElementType();
+    assert(PointeeType != nullptr && "PointeeType should always be available.");
+    QualType PointeeQualifiedType(PointeeType, 0);
+
+    if (PointeeType->isRecordType()) {
+      if (const RecordDecl *RD =
+              PointeeType->getAsRecordDecl()->getDefinition()) {
+        if (const auto *CXXDecl = dyn_cast<CXXRecordDecl>(RD)) {
+          if (!CXXDecl->isStandardLayout()) {
+            diag(CE->getBeginLoc(),
+                 "comparing object representation of non-standard-layout type "
+                 "%0; consider using a comparison operator instead")
+                << PointeeQualifiedType;
+            break;
+          }
+        }
+      }
+    }
+
+    if (!PointeeType->isIncompleteType()) {
+      uint64_t PointeeSize = Ctx.getTypeSize(PointeeType);
+      if (ComparedBits.hasValue() && *ComparedBits >= PointeeSize &&
+          !Ctx.hasUniqueObjectRepresentations(PointeeQualifiedType)) {
+        diag(CE->getBeginLoc(),
+             "comparing object representation of type %0 which does not have a "
+             "unique object representation; consider comparing %select{the "
+             "values|the members of the object}1 manually")
+            << PointeeQualifiedType << (PointeeType->isRecordType() ? 1 : 0);
+        break;
+      }
+    }
+  }
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/bugprone/SuspiciousMemoryComparisonCheck.h

@@ -0,0 +1,35 @@
+//===--- SuspiciousMemoryComparisonCheck.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_BUGPRONE_SUSPICIOUSMEMORYCOMPARISONCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SUSPICIOUSMEMORYCOMPARISONCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+/// Finds potentially incorrect calls to ``memcmp()`` based on properties of the
+/// arguments.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone-suspicious-memory-comparison.html
+class SuspiciousMemoryComparisonCheck : public ClangTidyCheck {
+public:
+  SuspiciousMemoryComparisonCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SUSPICIOUSMEMORYCOMPARISONCHECK_H

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

@@ -14,6 +14,7 @@
 #include "../bugprone/SignalHandlerCheck.h"
 #include "../bugprone/SignedCharMisuseCheck.h"
 #include "../bugprone/SpuriouslyWakeUpFunctionsCheck.h"
+#include "../bugprone/SuspiciousMemoryComparisonCheck.h"
 #include "../bugprone/UnhandledSelfAssignmentCheck.h"
 #include "../concurrency/ThreadCanceltypeAsynchronousCheck.h"
 #include "../google/UnnamedNamespaceInHeaderCheck.h"
@@ -98,8 +99,13 @@ class CERTModule : public ClangTidyModule {
         "cert-dcl37-c");
     // ENV
     CheckFactories.registerCheck<CommandProcessorCheck>("cert-env33-c");
+    // EXP
+    CheckFactories.registerCheck<bugprone::SuspiciousMemoryComparisonCheck>(
+        "cert-exp42-c");
     // FLP
     CheckFactories.registerCheck<FloatLoopCounter>("cert-flp30-c");
+    CheckFactories.registerCheck<bugprone::SuspiciousMemoryComparisonCheck>(
+        "cert-flp37-c");
     // FIO
     CheckFactories.registerCheck<misc::NonCopyableObjectsCheck>("cert-fio38-c");
     // ERR

clang-tools-extra/docs/ReleaseNotes.rst

@@ -72,6 +72,11 @@ The improvements are...
 New checks
 ^^^^^^^^^^
 
+- New :doc:`bugprone-suspicious-memory-comparison
+  <clang-tidy/checks/bugprone-suspicious-memory-comparison>` check.
+
+  Finds potentially incorrect calls to ``memcmp()`` based on properties of the arguments.
+
 - New :doc:`readability-identifier-length
   <clang-tidy/checks/readability-identifier-length>` check.
 
@@ -80,6 +85,16 @@ New checks
 New check aliases
 ^^^^^^^^^^^^^^^^^
 
+- New alias :doc:`cert-exp42-c
+  <clang-tidy/checks/cert-exp42-c>` to
+  :doc:`bugprone-suspicious-memory-comparison
+  <clang-tidy/checks/bugprone-suspicious-memory-comparison>` was added.
+
+- New alias :doc:`cert-flp37-c
+  <clang-tidy/checks/cert-flp37-c>` to
+  :doc:`bugprone-suspicious-memory-comparison
+  <clang-tidy/checks/bugprone-suspicious-memory-comparison>` was added.
+
 Changes in existing checks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 

clang-tools-extra/docs/clang-tidy/checks/bugprone-suspicious-memory-comparison.rst

@@ -0,0 +1,31 @@
+.. title:: clang-tidy - bugprone-suspicious-memory-comparison
+
+bugprone-suspicious-memory-comparison
+=====================================
+
+Finds potentially incorrect calls to ``memcmp()`` based on properties of the
+arguments. The following cases are covered:
+
+**Case 1: Non-standard-layout type**
+
+Comparing the object representaions of non-standard-layout objects may not
+properly compare the value representations.
+
+**Case 2: Types with no unique object representation**
+
+Objects with the same value may not have the same object representaion.
+This may be caused by padding or floating-point types.
+
+See also: 
+`EXP42-C. Do not compare padding data
+<https://wiki.sei.cmu.edu/confluence/display/c/EXP42-C.+Do+not+compare+padding+data>`_
+and
+`FLP37-C. Do not use object representations to compare floating-point values
+<https://wiki.sei.cmu.edu/confluence/display/c/FLP37-C.+Do+not+use+object+representations+to+compare+floating-point+values>`_
+
+This check is also related to and partially overlaps the CERT C++ Coding Standard rules 
+`OOP57-CPP. Prefer special member functions and overloaded operators to C Standard Library functions
+<https://wiki.sei.cmu.edu/confluence/display/cplusplus/OOP57-CPP.+Prefer+special+member+functions+and+overloaded+operators+to+C+Standard+Library+functions>`_
+and
+`EXP62-CPP. Do not access the bits of an object representation that are not part of the object's value representation
+<https://wiki.sei.cmu.edu/confluence/display/cplusplus/EXP62-CPP.+Do+not+access+the+bits+of+an+object+representation+that+are+not+part+of+the+object%27s+value+representation>`_

clang-tools-extra/docs/clang-tidy/checks/cert-exp42-c.rst

@@ -0,0 +1,8 @@
+.. meta::
+   :http-equiv=refresh: 5;URL=bugprone-suspicious-memory-comparison.html
+
+cert-exp42-c
+============
+
+The cert-exp42-c check is an alias, please see
+`bugprone-suspicious-memory-comparison <bugprone-suspicious-memory-comparison.html>`_ for more information.

clang-tools-extra/docs/clang-tidy/checks/cert-flp37-c.rst

@@ -0,0 +1,8 @@
+.. meta::
+   :http-equiv=refresh: 5;URL=bugprone-suspicious-memory-comparison.html
+
+cert-flp37-c
+============
+
+The cert-flp37-c check is an alias, please see
+`bugprone-suspicious-memory-comparison <bugprone-suspicious-memory-comparison.html>`_ for more information.

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -93,6 +93,7 @@ Clang-Tidy Checks
    `bugprone-string-literal-with-embedded-nul <bugprone-string-literal-with-embedded-nul.html>`_,
    `bugprone-suspicious-enum-usage <bugprone-suspicious-enum-usage.html>`_,
    `bugprone-suspicious-include <bugprone-suspicious-include.html>`_,
+   `bugprone-suspicious-memory-comparison <bugprone-suspicious-memory-comparison.html>`_,
    `bugprone-suspicious-memset-usage <bugprone-suspicious-memset-usage.html>`_, "Yes"
    `bugprone-suspicious-missing-comma <bugprone-suspicious-missing-comma.html>`_,
    `bugprone-suspicious-semicolon <bugprone-suspicious-semicolon.html>`_, "Yes"
@@ -117,7 +118,9 @@ Clang-Tidy Checks
    `cert-err52-cpp <cert-err52-cpp.html>`_,
    `cert-err58-cpp <cert-err58-cpp.html>`_,
    `cert-err60-cpp <cert-err60-cpp.html>`_,
+   `cert-exp42-c <cert-exp42-c.html>`_,
    `cert-flp30-c <cert-flp30-c.html>`_,
+   `cert-flp37-c <cert-flp37-c.html>`_,
    `cert-mem57-cpp <cert-mem57-cpp.html>`_,
    `cert-msc50-cpp <cert-msc50-cpp.html>`_,
    `cert-msc51-cpp <cert-msc51-cpp.html>`_,

clang-tools-extra/test/clang-tidy/checkers/bugprone-suspicious-memory-comparison-32bits.cpp

@@ -0,0 +1,33 @@
+// RUN: %check_clang_tidy %s bugprone-suspicious-memory-comparison %t \
+// RUN: -- -- -target i386-unknown-unknown
+
+static_assert(sizeof(int *) == sizeof(int));
+
+namespace std {
+typedef __SIZE_TYPE__ size_t;
+int memcmp(const void *lhs, const void *rhs, size_t count);
+} // namespace std
+
+namespace no_padding_on_32bit {
+struct S {
+  int x;
+  int *y;
+};
+
+void test() {
+  S a, b;
+  std::memcmp(&a, &b, sizeof(S));
+}
+} // namespace no_padding_on_32bit
+
+namespace inner_padding {
+struct S {
+  char x;
+  int y;
+};
+void test() {
+  S a, b;
+  std::memcmp(&a, &b, sizeof(S));
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: comparing object representation of type 'inner_padding::S' which does not have a unique object representation; consider comparing the members of the object manually
+}
+} // namespace inner_padding