r369217 - [Diagnostics] Diagnose misused xor as pow
David Bolvansky via cfe-commits
cfe-commits at lists.llvm.org
Sun Aug 18 12:14:14 PDT 2019
Author: xbolva00
Date: Sun Aug 18 12:14:14 2019
New Revision: 369217
URL: http://llvm.org/viewvc/llvm-project?rev=369217&view=rev
Log:
[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
Added:
cfe/trunk/test/SemaCXX/warn-xor-as-pow.cpp
Modified:
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaExpr.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=369217&r1=369216&r2=369217&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Sun Aug 18 12:14:14 2019
@@ -512,6 +512,7 @@ def CompareDistinctPointerType : DiagGro
def GNUUnionCast : DiagGroup<"gnu-union-cast">;
def GNUVariableSizedTypeNotAtEnd : DiagGroup<"gnu-variable-sized-type-not-at-end">;
def Varargs : DiagGroup<"varargs">;
+def XorUsedAsPow : DiagGroup<"xor-used-as-pow">;
def Unsequenced : DiagGroup<"unsequenced">;
// GCC name for -Wunsequenced
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=369217&r1=369216&r2=369217&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Sun Aug 18 12:14:14 2019
@@ -3326,6 +3326,15 @@ def warn_address_of_reference_bool_conve
"code; pointer may be assumed to always convert to true">,
InGroup<UndefinedBoolConversion>;
+def warn_xor_used_as_pow_base_extra : Warning<
+ "result of '%0' is %1; did you mean '%2' (%3)?">,
+ InGroup<XorUsedAsPow>;
+def warn_xor_used_as_pow_base : Warning<
+ "result of '%0' is %1; did you mean '%2'?">,
+ InGroup<XorUsedAsPow>;
+def note_xor_used_as_pow_silence : Note<
+ "replace expression with '%0' to silence this warning">;
+
def warn_null_pointer_compare : Warning<
"comparison of %select{address of|function|array}0 '%1' %select{not |}2"
"equal to a null pointer is always %select{true|false}2">,
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=369217&r1=369216&r2=369217&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Sun Aug 18 12:14:14 2019
@@ -11011,6 +11011,107 @@ QualType Sema::CheckVectorCompareOperand
return GetSignedVectorType(vType);
}
+static void diagnoseXorMisusedAsPow(Sema &S, ExprResult &LHS, ExprResult &RHS,
+ SourceLocation Loc) {
+ // Do not diagnose macros.
+ if (Loc.isMacroID())
+ return;
+
+ bool Negative = false;
+ const auto *LHSInt = dyn_cast<IntegerLiteral>(LHS.get());
+ const auto *RHSInt = dyn_cast<IntegerLiteral>(RHS.get());
+
+ if (!LHSInt)
+ return;
+ if (!RHSInt) {
+ // Check negative literals.
+ if (const auto *UO = dyn_cast<UnaryOperator>(RHS.get())) {
+ if (UO->getOpcode() != UO_Minus)
+ return;
+ RHSInt = dyn_cast<IntegerLiteral>(UO->getSubExpr());
+ if (!RHSInt)
+ return;
+ Negative = true;
+ } else {
+ return;
+ }
+ }
+
+ if (LHSInt->getValue().getBitWidth() != RHSInt->getValue().getBitWidth())
+ return;
+
+ CharSourceRange ExprRange = CharSourceRange::getCharRange(
+ LHSInt->getBeginLoc(), S.getLocForEndOfToken(RHSInt->getLocation()));
+ llvm::StringRef ExprStr =
+ Lexer::getSourceText(ExprRange, S.getSourceManager(), S.getLangOpts());
+
+ CharSourceRange XorRange =
+ CharSourceRange::getCharRange(Loc, S.getLocForEndOfToken(Loc));
+ llvm::StringRef XorStr =
+ Lexer::getSourceText(XorRange, S.getSourceManager(), S.getLangOpts());
+ // Do not diagnose if xor keyword/macro is used.
+ if (XorStr == "xor")
+ return;
+
+ const llvm::APInt &LeftSideValue = LHSInt->getValue();
+ const llvm::APInt &RightSideValue = RHSInt->getValue();
+ const llvm::APInt XorValue = LeftSideValue ^ RightSideValue;
+
+ std::string LHSStr = Lexer::getSourceText(
+ CharSourceRange::getTokenRange(LHSInt->getSourceRange()),
+ S.getSourceManager(), S.getLangOpts());
+ std::string RHSStr = Lexer::getSourceText(
+ CharSourceRange::getTokenRange(RHSInt->getSourceRange()),
+ S.getSourceManager(), S.getLangOpts());
+
+ int64_t RightSideIntValue = RightSideValue.getSExtValue();
+ if (Negative) {
+ RightSideIntValue = -RightSideIntValue;
+ RHSStr = "-" + RHSStr;
+ }
+
+ StringRef LHSStrRef = LHSStr;
+ StringRef RHSStrRef = RHSStr;
+ // Do not diagnose binary, hexadecimal, octal literals.
+ if (LHSStrRef.startswith("0b") || LHSStrRef.startswith("0B") ||
+ RHSStrRef.startswith("0b") || RHSStrRef.startswith("0B") ||
+ LHSStrRef.startswith("0x") || LHSStrRef.startswith("0X") ||
+ RHSStrRef.startswith("0x") || RHSStrRef.startswith("0X") ||
+ (LHSStrRef.size() > 1 && LHSStrRef.startswith("0")) ||
+ (RHSStrRef.size() > 1 && RHSStrRef.startswith("0")))
+ return;
+
+ if (LeftSideValue == 2 && RightSideIntValue >= 0) {
+ std::string SuggestedExpr = "1 << " + RHSStr;
+ bool Overflow = false;
+ llvm::APInt One = (LeftSideValue - 1);
+ llvm::APInt PowValue = One.sshl_ov(RightSideValue, Overflow);
+ if (Overflow) {
+ if (RightSideIntValue < 64)
+ S.Diag(Loc, diag::warn_xor_used_as_pow_base)
+ << ExprStr << XorValue.toString(10, true) << ("1LL << " + RHSStr)
+ << FixItHint::CreateReplacement(ExprRange, "1LL << " + RHSStr);
+ else
+ // TODO: 2 ^ 64 - 1
+ return;
+ } else {
+ S.Diag(Loc, diag::warn_xor_used_as_pow_base_extra)
+ << ExprStr << XorValue.toString(10, true) << SuggestedExpr
+ << PowValue.toString(10, true)
+ << FixItHint::CreateReplacement(
+ ExprRange, (RightSideIntValue == 0) ? "1" : SuggestedExpr);
+ }
+
+ S.Diag(Loc, diag::note_xor_used_as_pow_silence) << ("0x2 ^ " + RHSStr);
+ } else if (LeftSideValue == 10) {
+ std::string SuggestedValue = "1e" + std::to_string(RightSideIntValue);
+ S.Diag(Loc, diag::warn_xor_used_as_pow_base)
+ << ExprStr << XorValue.toString(10, true) << SuggestedValue
+ << FixItHint::CreateReplacement(ExprRange, SuggestedValue);
+ S.Diag(Loc, diag::note_xor_used_as_pow_silence) << ("0xA ^ " + RHSStr);
+ }
+}
+
QualType Sema::CheckVectorLogicalOperands(ExprResult &LHS, ExprResult &RHS,
SourceLocation Loc) {
// Ensure that either both operands are of the same vector type, or
@@ -11054,6 +11155,9 @@ inline QualType Sema::CheckBitwiseOperan
if (Opc == BO_And)
diagnoseLogicalNotOnLHSofCheck(*this, LHS, RHS, Loc, Opc);
+ if (Opc == BO_Xor)
+ diagnoseXorMisusedAsPow(*this, LHS, RHS, Loc);
+
ExprResult LHSResult = LHS, RHSResult = RHS;
QualType compType = UsualArithmeticConversions(LHSResult, RHSResult,
IsCompAssign);
@@ -17640,4 +17744,4 @@ ExprResult Sema::ActOnObjCAvailabilityCh
return new (Context)
ObjCAvailabilityCheckExpr(Version, AtLoc, RParen, Context.BoolTy);
-}
+}
\ No newline at end of file
Added: cfe/trunk/test/SemaCXX/warn-xor-as-pow.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-xor-as-pow.cpp?rev=369217&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/warn-xor-as-pow.cpp (added)
+++ cfe/trunk/test/SemaCXX/warn-xor-as-pow.cpp Sun Aug 18 12:14:14 2019
@@ -0,0 +1,105 @@
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wxor-used-as-pow %s
+// RUN: %clang_cc1 -x c -fsyntax-only -verify %s
+// RUN: %clang_cc1 -x c -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wxor-used-as-pow %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+#define FOOBAR(x, y) (x * y)
+#define XOR(x, y) (x ^ y)
+#define TWO 2
+#define TEN 10
+#define TWO_ULL 2ULL
+#define EPSILON 10 ^ -300
+
+#define flexor 7
+
+#ifdef __cplusplus
+constexpr long long operator"" _xor(unsigned long long v) { return v; }
+
+constexpr long long operator"" _0b(unsigned long long v) { return v; }
+constexpr long long operator"" _0X(unsigned long long v) { return v; }
+#else
+#define xor ^ // iso646.h
+#endif
+
+void test(unsigned a, unsigned b) {
+ unsigned res;
+ res = a ^ 5;
+ res = 2 ^ b;
+ res = a ^ b;
+ res = 2 ^ -1;
+ res = 2 ^ 0; // expected-warning {{result of '2 ^ 0' is 2; did you mean '1 << 0' (1)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1"
+ // expected-note at -2 {{replace expression with '0x2 ^ 0' to silence this warning}}
+ res = 2 ^ 1; // expected-warning {{result of '2 ^ 1' is 3; did you mean '1 << 1' (2)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 1"
+ // expected-note at -2 {{replace expression with '0x2 ^ 1' to silence this warning}}
+ res = 2 ^ 2; // expected-warning {{result of '2 ^ 2' is 0; did you mean '1 << 2' (4)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 2"
+ // expected-note at -2 {{replace expression with '0x2 ^ 2' to silence this warning}}
+ res = 2 ^ 8; // expected-warning {{result of '2 ^ 8' is 10; did you mean '1 << 8' (256)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:14}:"1 << 8"
+ // expected-note at -2 {{replace expression with '0x2 ^ 8' to silence this warning}}
+ res = TWO ^ 8; // expected-warning {{result of 'TWO ^ 8' is 10; did you mean '1 << 8' (256)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1 << 8"
+ // expected-note at -2 {{replace expression with '0x2 ^ 8' to silence this warning}}
+ res = 2 ^ 16; // expected-warning {{result of '2 ^ 16' is 18; did you mean '1 << 16' (65536)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1 << 16"
+ // expected-note at -2 {{replace expression with '0x2 ^ 16' to silence this warning}}
+ res = 2 ^ TEN; // expected-warning {{result of '2 ^ TEN' is 8; did you mean '1 << TEN' (1024)?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1 << TEN"
+ // expected-note at -2 {{replace expression with '0x2 ^ TEN' to silence this warning}}
+ res = 0x2 ^ 16;
+ res = 2 xor 16;
+
+ res = 2 ^ 0x4;
+ res = 2 ^ 04;
+ res = 0x2 ^ 10;
+ res = 0X2 ^ 10;
+ res = 02 ^ 10;
+ res = FOOBAR(2, 16);
+ res = 0b10 ^ 16;
+ res = 0B10 ^ 16;
+ res = 2 ^ 0b100;
+ res = XOR(2, 16);
+ unsigned char two = 2;
+ res = two ^ 16;
+ res = TWO_ULL ^ 16;
+ res = 2 ^ 32; // expected-warning {{result of '2 ^ 32' is 34; did you mean '1LL << 32'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1LL << 32"
+ // expected-note at -2 {{replace expression with '0x2 ^ 32' to silence this warning}}
+ res = 2 ^ 64;
+
+ res = EPSILON;
+ res = 10 ^ 0; // expected-warning {{result of '10 ^ 0' is 10; did you mean '1e0'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e0"
+ // expected-note at -2 {{replace expression with '0xA ^ 0' to silence this warning}}
+ res = 10 ^ 1; // expected-warning {{result of '10 ^ 1' is 11; did you mean '1e1'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e1"
+ // expected-note at -2 {{replace expression with '0xA ^ 1' to silence this warning}}
+ res = 10 ^ 2; // expected-warning {{result of '10 ^ 2' is 8; did you mean '1e2'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e2"
+ // expected-note at -2 {{replace expression with '0xA ^ 2' to silence this warning}}
+ res = 10 ^ 4; // expected-warning {{result of '10 ^ 4' is 14; did you mean '1e4'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:15}:"1e4"
+ // expected-note at -2 {{replace expression with '0xA ^ 4' to silence this warning}}
+ res = 10 ^ 10; // expected-warning {{result of '10 ^ 10' is 0; did you mean '1e10'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:16}:"1e10"
+ // expected-note at -2 {{replace expression with '0xA ^ 10' to silence this warning}}
+ res = TEN ^ 10; // expected-warning {{result of 'TEN ^ 10' is 0; did you mean '1e10'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:17}:"1e10"
+ // expected-note at -2 {{replace expression with '0xA ^ 10' to silence this warning}}
+ res = 10 ^ 100; // expected-warning {{result of '10 ^ 100' is 110; did you mean '1e100'?}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:9-[[@LINE-1]]:17}:"1e100"
+ // expected-note at -2 {{replace expression with '0xA ^ 100' to silence this warning}}
+ res = 0xA ^ 10;
+ res = 10 xor 10;
+#ifdef __cplusplus
+ res = 10 ^ 5_xor;
+ res = 10_xor ^ 5;
+ res = 10 ^ 5_0b;
+ res = 10_0X ^ 5;
+#endif
+}
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