forked from OSchip/llvm-project
[Diagnostics] Diagnose misused xor as pow
Summary: Motivation: https://twitter.com/jfbastien/status/1139298419988549632 https://twitter.com/mikemx7f/status/1139335901790625793 https://codesearch.isocpp.org/cgi-bin/cgi_ppsearch?q=10+%5E&search=Search Reviewers: jfb, rsmith, regehr, aaron.ballman Reviewed By: aaron.ballman Subscribers: lebedev.ri, Quuxplusone, erik.pilkington, riccibruno, dexonsmith, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D63423 llvm-svn: 369217
This commit is contained in:
David Bolvansky
parent
c944438dfd
commit
920890e268
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@ -512,6 +512,7 @@ def CompareDistinctPointerType : DiagGroup<"compare-distinct-pointer-types">;
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def GNUUnionCast : DiagGroup<"gnu-union-cast">;
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def GNUVariableSizedTypeNotAtEnd : DiagGroup<"gnu-variable-sized-type-not-at-end">;
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def Varargs : DiagGroup<"varargs">;
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def XorUsedAsPow : DiagGroup<"xor-used-as-pow">;
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def Unsequenced : DiagGroup<"unsequenced">;
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// GCC name for -Wunsequenced
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@ -3326,6 +3326,15 @@ def warn_address_of_reference_bool_conversion : Warning<
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"code; pointer may be assumed to always convert to true">,
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InGroup<UndefinedBoolConversion>;
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def warn_xor_used_as_pow_base_extra : Warning<
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"result of '%0' is %1; did you mean '%2' (%3)?">,
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InGroup<XorUsedAsPow>;
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def warn_xor_used_as_pow_base : Warning<
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"result of '%0' is %1; did you mean '%2'?">,
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InGroup<XorUsedAsPow>;
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def note_xor_used_as_pow_silence : Note<
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"replace expression with '%0' to silence this warning">;
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def warn_null_pointer_compare : Warning<
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"comparison of %select{address of|function|array}0 '%1' %select{not |}2"
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"equal to a null pointer is always %select{true|false}2">,
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@ -11011,6 +11011,107 @@ QualType Sema::CheckVectorCompareOperands(ExprResult &LHS, ExprResult &RHS,
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return GetSignedVectorType(vType);
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}
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static void diagnoseXorMisusedAsPow(Sema &S, ExprResult &LHS, ExprResult &RHS,
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SourceLocation Loc) {
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// Do not diagnose macros.
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if (Loc.isMacroID())
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return;
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bool Negative = false;
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const auto *LHSInt = dyn_cast<IntegerLiteral>(LHS.get());
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const auto *RHSInt = dyn_cast<IntegerLiteral>(RHS.get());
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if (!LHSInt)
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return;
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if (!RHSInt) {
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// Check negative literals.
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if (const auto *UO = dyn_cast<UnaryOperator>(RHS.get())) {
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if (UO->getOpcode() != UO_Minus)
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return;
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RHSInt = dyn_cast<IntegerLiteral>(UO->getSubExpr());
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if (!RHSInt)
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return;
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Negative = true;
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} else {
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return;
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}
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}
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if (LHSInt->getValue().getBitWidth() != RHSInt->getValue().getBitWidth())
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return;
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CharSourceRange ExprRange = CharSourceRange::getCharRange(
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LHSInt->getBeginLoc(), S.getLocForEndOfToken(RHSInt->getLocation()));
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llvm::StringRef ExprStr =
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Lexer::getSourceText(ExprRange, S.getSourceManager(), S.getLangOpts());
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CharSourceRange XorRange =
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CharSourceRange::getCharRange(Loc, S.getLocForEndOfToken(Loc));
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llvm::StringRef XorStr =
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Lexer::getSourceText(XorRange, S.getSourceManager(), S.getLangOpts());
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// Do not diagnose if xor keyword/macro is used.
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if (XorStr == "xor")
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return;
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const llvm::APInt &LeftSideValue = LHSInt->getValue();
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const llvm::APInt &RightSideValue = RHSInt->getValue();
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const llvm::APInt XorValue = LeftSideValue ^ RightSideValue;
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std::string LHSStr = Lexer::getSourceText(
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CharSourceRange::getTokenRange(LHSInt->getSourceRange()),
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S.getSourceManager(), S.getLangOpts());
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std::string RHSStr = Lexer::getSourceText(
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CharSourceRange::getTokenRange(RHSInt->getSourceRange()),
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S.getSourceManager(), S.getLangOpts());
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int64_t RightSideIntValue = RightSideValue.getSExtValue();
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if (Negative) {
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RightSideIntValue = -RightSideIntValue;
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RHSStr = "-" + RHSStr;
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}
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StringRef LHSStrRef = LHSStr;
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StringRef RHSStrRef = RHSStr;
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// Do not diagnose binary, hexadecimal, octal literals.
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if (LHSStrRef.startswith("0b") || LHSStrRef.startswith("0B") ||
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RHSStrRef.startswith("0b") || RHSStrRef.startswith("0B") ||
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LHSStrRef.startswith("0x") || LHSStrRef.startswith("0X") ||
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RHSStrRef.startswith("0x") || RHSStrRef.startswith("0X") ||
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(LHSStrRef.size() > 1 && LHSStrRef.startswith("0")) ||
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(RHSStrRef.size() > 1 && RHSStrRef.startswith("0")))
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return;
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if (LeftSideValue == 2 && RightSideIntValue >= 0) {
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std::string SuggestedExpr = "1 << " + RHSStr;
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bool Overflow = false;
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llvm::APInt One = (LeftSideValue - 1);
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llvm::APInt PowValue = One.sshl_ov(RightSideValue, Overflow);
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if (Overflow) {
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if (RightSideIntValue < 64)
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S.Diag(Loc, diag::warn_xor_used_as_pow_base)
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<< ExprStr << XorValue.toString(10, true) << ("1LL << " + RHSStr)
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<< FixItHint::CreateReplacement(ExprRange, "1LL << " + RHSStr);
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else
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// TODO: 2 ^ 64 - 1
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return;
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} else {
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S.Diag(Loc, diag::warn_xor_used_as_pow_base_extra)
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<< ExprStr << XorValue.toString(10, true) << SuggestedExpr
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<< PowValue.toString(10, true)
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<< FixItHint::CreateReplacement(
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ExprRange, (RightSideIntValue == 0) ? "1" : SuggestedExpr);
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}
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S.Diag(Loc, diag::note_xor_used_as_pow_silence) << ("0x2 ^ " + RHSStr);
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} else if (LeftSideValue == 10) {
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std::string SuggestedValue = "1e" + std::to_string(RightSideIntValue);
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S.Diag(Loc, diag::warn_xor_used_as_pow_base)
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<< ExprStr << XorValue.toString(10, true) << SuggestedValue
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<< FixItHint::CreateReplacement(ExprRange, SuggestedValue);
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S.Diag(Loc, diag::note_xor_used_as_pow_silence) << ("0xA ^ " + RHSStr);
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}
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}
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QualType Sema::CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
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SourceLocation Loc) {
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// Ensure that either both operands are of the same vector type, or
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@ -11054,6 +11155,9 @@ inline QualType Sema::CheckBitwiseOperands(ExprResult &LHS, ExprResult &RHS,
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if (Opc == BO_And)
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diagnoseLogicalNotOnLHSofCheck(*this, LHS, RHS, Loc, Opc);
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if (Opc == BO_Xor)
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diagnoseXorMisusedAsPow(*this, LHS, RHS, Loc);
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ExprResult LHSResult = LHS, RHSResult = RHS;
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QualType compType = UsualArithmeticConversions(LHSResult, RHSResult,
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IsCompAssign);
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@ -17640,4 +17744,4 @@ ExprResult Sema::ActOnObjCAvailabilityCheckExpr(
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return new (Context)
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ObjCAvailabilityCheckExpr(Version, AtLoc, RParen, Context.BoolTy);
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}
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}
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@ -0,0 +1,105 @@
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// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wxor-used-as-pow %s
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// RUN: %clang_cc1 -x c -fsyntax-only -verify %s
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// RUN: %clang_cc1 -x c -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
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// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wxor-used-as-pow %s
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// RUN: %clang_cc1 -x c++ -fsyntax-only -verify %s
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// RUN: %clang_cc1 -x c++ -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
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#define FOOBAR(x, y) (x * y)
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#define XOR(x, y) (x ^ y)
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#define TWO 2
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#define TEN 10
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#define TWO_ULL 2ULL
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#define EPSILON 10 ^ -300
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#define flexor 7
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#ifdef __cplusplus
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constexpr long long operator"" _xor(unsigned long long v) { return v; }
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constexpr long long operator"" _0b(unsigned long long v) { return v; }
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constexpr long long operator"" _0X(unsigned long long v) { return v; }
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#else
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#define xor ^ // iso646.h
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#endif
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void test(unsigned a, unsigned b) {
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unsigned res;
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res = a ^ 5;
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res = 2 ^ b;
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res = a ^ b;
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res = 2 ^ -1;
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res = 2 ^ 0; // expected-warning {{result of '2 ^ 0' is 2; did you mean '1 << 0' (1)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1"
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// expected-note@-2 {{replace expression with '0x2 ^ 0' to silence this warning}}
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res = 2 ^ 1; // expected-warning {{result of '2 ^ 1' is 3; did you mean '1 << 1' (2)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 1"
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// expected-note@-2 {{replace expression with '0x2 ^ 1' to silence this warning}}
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res = 2 ^ 2; // expected-warning {{result of '2 ^ 2' is 0; did you mean '1 << 2' (4)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 2"
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// expected-note@-2 {{replace expression with '0x2 ^ 2' to silence this warning}}
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res = 2 ^ 8; // expected-warning {{result of '2 ^ 8' is 10; did you mean '1 << 8' (256)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 8"
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// expected-note@-2 {{replace expression with '0x2 ^ 8' to silence this warning}}
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res = TWO ^ 8; // expected-warning {{result of 'TWO ^ 8' is 10; did you mean '1 << 8' (256)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1 << 8"
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// expected-note@-2 {{replace expression with '0x2 ^ 8' to silence this warning}}
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res = 2 ^ 16; // expected-warning {{result of '2 ^ 16' is 18; did you mean '1 << 16' (65536)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1 << 16"
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// expected-note@-2 {{replace expression with '0x2 ^ 16' to silence this warning}}
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res = 2 ^ TEN; // expected-warning {{result of '2 ^ TEN' is 8; did you mean '1 << TEN' (1024)?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1 << TEN"
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// expected-note@-2 {{replace expression with '0x2 ^ TEN' to silence this warning}}
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res = 0x2 ^ 16;
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res = 2 xor 16;
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res = 2 ^ 0x4;
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res = 2 ^ 04;
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res = 0x2 ^ 10;
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res = 0X2 ^ 10;
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res = 02 ^ 10;
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res = FOOBAR(2, 16);
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res = 0b10 ^ 16;
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res = 0B10 ^ 16;
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res = 2 ^ 0b100;
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res = XOR(2, 16);
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unsigned char two = 2;
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res = two ^ 16;
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res = TWO_ULL ^ 16;
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res = 2 ^ 32; // expected-warning {{result of '2 ^ 32' is 34; did you mean '1LL << 32'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1LL << 32"
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// expected-note@-2 {{replace expression with '0x2 ^ 32' to silence this warning}}
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res = 2 ^ 64;
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res = EPSILON;
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res = 10 ^ 0; // expected-warning {{result of '10 ^ 0' is 10; did you mean '1e0'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e0"
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// expected-note@-2 {{replace expression with '0xA ^ 0' to silence this warning}}
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res = 10 ^ 1; // expected-warning {{result of '10 ^ 1' is 11; did you mean '1e1'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e1"
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// expected-note@-2 {{replace expression with '0xA ^ 1' to silence this warning}}
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res = 10 ^ 2; // expected-warning {{result of '10 ^ 2' is 8; did you mean '1e2'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e2"
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// expected-note@-2 {{replace expression with '0xA ^ 2' to silence this warning}}
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res = 10 ^ 4; // expected-warning {{result of '10 ^ 4' is 14; did you mean '1e4'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e4"
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// expected-note@-2 {{replace expression with '0xA ^ 4' to silence this warning}}
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res = 10 ^ 10; // expected-warning {{result of '10 ^ 10' is 0; did you mean '1e10'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1e10"
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// expected-note@-2 {{replace expression with '0xA ^ 10' to silence this warning}}
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res = TEN ^ 10; // expected-warning {{result of 'TEN ^ 10' is 0; did you mean '1e10'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:17}:"1e10"
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// expected-note@-2 {{replace expression with '0xA ^ 10' to silence this warning}}
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res = 10 ^ 100; // expected-warning {{result of '10 ^ 100' is 110; did you mean '1e100'?}}
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// CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:17}:"1e100"
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// expected-note@-2 {{replace expression with '0xA ^ 100' to silence this warning}}
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res = 0xA ^ 10;
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res = 10 xor 10;
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#ifdef __cplusplus
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res = 10 ^ 5_xor;
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res = 10_xor ^ 5;
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res = 10 ^ 5_0b;
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res = 10_0X ^ 5;
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#endif
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}
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