danielmarjamaki created this revision.
danielmarjamaki added reviewers: dblaikie, rtrieu.
danielmarjamaki added a subscriber: cfe-commits.
danielmarjamaki set the repository for this revision to rL LLVM.
This patch makes Clang warn about following code:
a = (b * c >> 2);
It might be a good idea to use parentheses to clarify the operator precedence.
Repository:
rL LLVM
https://reviews.llvm.org/D24861
Files:
lib/Sema/SemaExpr.cpp
test/Sema/parentheses.cpp
Index: test/Sema/parentheses.cpp
===================================================================
--- test/Sema/parentheses.cpp
+++ test/Sema/parentheses.cpp
@@ -95,6 +95,21 @@
// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+ (void)(a >> b * c); // expected-warning {{operator '>>' has lower precedence
than '*'; '*' will be evaluated first}} \
+ expected-note {{place parentheses around the '*'
expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:20}:")"
+
+ (void)(a / b << c); // expected-warning {{operator '<<' has lower precedence
than '/'; '/' will be evaluated first}} \
+ expected-note {{place parentheses around the '/'
expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
+ (void)(a % b << c); // expected-warning {{operator '<<' has lower precedence
than '%'; '%' will be evaluated first}} \
+ expected-note {{place parentheses around the '%'
expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
Stream() << b + c;
Stream() >> b + c; // expected-warning {{operator '>>' has lower precedence
than '+'; '+' will be evaluated first}} \
expected-note {{place parentheses around the '+'
expression to silence this warning}}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11246,10 +11246,10 @@
}
}
-static void DiagnoseAdditionInShift(Sema &S, SourceLocation OpLoc,
+static void DiagnoseAddOrMulInShift(Sema &S, SourceLocation OpLoc,
Expr *SubExpr, StringRef Shift) {
if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(SubExpr)) {
- if (Bop->getOpcode() == BO_Add || Bop->getOpcode() == BO_Sub) {
+ if (Bop->isAdditiveOp() || Bop->isMultiplicativeOp()) {
StringRef Op = Bop->getOpcodeStr();
S.Diag(Bop->getOperatorLoc(), diag::warn_addition_in_bitshift)
<< Bop->getSourceRange() << OpLoc << Shift << Op;
@@ -11313,8 +11313,8 @@
if ((Opc == BO_Shl &&
LHSExpr->getType()->isIntegralType(Self.getASTContext()))
|| Opc == BO_Shr) {
StringRef Shift = BinaryOperator::getOpcodeStr(Opc);
- DiagnoseAdditionInShift(Self, OpLoc, LHSExpr, Shift);
- DiagnoseAdditionInShift(Self, OpLoc, RHSExpr, Shift);
+ DiagnoseAddOrMulInShift(Self, OpLoc, LHSExpr, Shift);
+ DiagnoseAddOrMulInShift(Self, OpLoc, RHSExpr, Shift);
}
// Warn on overloaded shift operators and comparisons, such as:
Index: test/Sema/parentheses.cpp
===================================================================
--- test/Sema/parentheses.cpp
+++ test/Sema/parentheses.cpp
@@ -95,6 +95,21 @@
// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
// CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+ (void)(a >> b * c); // expected-warning {{operator '>>' has lower precedence than '*'; '*' will be evaluated first}} \
+ expected-note {{place parentheses around the '*' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:20-[[@LINE-3]]:20}:")"
+
+ (void)(a / b << c); // expected-warning {{operator '<<' has lower precedence than '/'; '/' will be evaluated first}} \
+ expected-note {{place parentheses around the '/' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
+ (void)(a % b << c); // expected-warning {{operator '<<' has lower precedence than '%'; '%' will be evaluated first}} \
+ expected-note {{place parentheses around the '%' expression to silence this warning}}
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:10-[[@LINE-2]]:10}:"("
+ // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:15-[[@LINE-3]]:15}:")"
+
Stream() << b + c;
Stream() >> b + c; // expected-warning {{operator '>>' has lower precedence than '+'; '+' will be evaluated first}} \
expected-note {{place parentheses around the '+' expression to silence this warning}}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11246,10 +11246,10 @@
}
}
-static void DiagnoseAdditionInShift(Sema &S, SourceLocation OpLoc,
+static void DiagnoseAddOrMulInShift(Sema &S, SourceLocation OpLoc,
Expr *SubExpr, StringRef Shift) {
if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(SubExpr)) {
- if (Bop->getOpcode() == BO_Add || Bop->getOpcode() == BO_Sub) {
+ if (Bop->isAdditiveOp() || Bop->isMultiplicativeOp()) {
StringRef Op = Bop->getOpcodeStr();
S.Diag(Bop->getOperatorLoc(), diag::warn_addition_in_bitshift)
<< Bop->getSourceRange() << OpLoc << Shift << Op;
@@ -11313,8 +11313,8 @@
if ((Opc == BO_Shl && LHSExpr->getType()->isIntegralType(Self.getASTContext()))
|| Opc == BO_Shr) {
StringRef Shift = BinaryOperator::getOpcodeStr(Opc);
- DiagnoseAdditionInShift(Self, OpLoc, LHSExpr, Shift);
- DiagnoseAdditionInShift(Self, OpLoc, RHSExpr, Shift);
+ DiagnoseAddOrMulInShift(Self, OpLoc, LHSExpr, Shift);
+ DiagnoseAddOrMulInShift(Self, OpLoc, RHSExpr, Shift);
}
// Warn on overloaded shift operators and comparisons, such as:
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