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[analyzer] Check all conditions in a chained if against each other. 

Like the binary operator check of r201702, this actually checks the
condition of every if in a chain against every other condition, an
O(N^2) operation. In most cases N should be small enough to make this
practical, and checking all cases like this makes it much more likely
to catch a copy-paste error within the same series of branches.

Part of IdenticalExprChecker; patch by Daniel Fahlgren!

llvm-svn: 203585
This commit is contained in:
Jordan Rose 2014-03-11 16:52:29 +00:00
parent b708306128
commit a6839aaa9b
2 changed files with 129 additions and 0 deletions
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24
clang/lib/StaticAnalyzer/Checkers/IdenticalExprChecker.cpp
View File

@ -108,6 +108,30 @@ bool FindIdenticalExprVisitor::VisitIfStmt(const IfStmt *I) {
const Stmt *Stmt1 = I->getThen();
const Stmt *Stmt2 = I->getElse();
// Check for identical conditions:
//
// if (b) {
// foo1();
// } else if (b) {
// foo2();
// }
if (Stmt1 && Stmt2) {
const Expr *Cond1 = I->getCond();
const Stmt *Else = Stmt2;
while (const IfStmt *I2 = dyn_cast_or_null<IfStmt>(Else)) {
const Expr *Cond2 = I2->getCond();
if (isIdenticalStmt(AC->getASTContext(), Cond1, Cond2, false)) {
SourceRange Sr = Cond1->getSourceRange();
PathDiagnosticLocation ELoc(Cond2, BR.getSourceManager(), AC);
BR.EmitBasicReport(AC->getDecl(), Checker, "Identical conditions",
categories::LogicError,
"expression is identical to previous condition",
ELoc, Sr);
}
Else = I2->getElse();
}
}
if (!Stmt1 || !Stmt2)
return true;

105
clang/test/Analysis/identical-expressions.cpp
View File

@ -1406,3 +1406,108 @@ void test_identical_logical9(int x, int y) {
;
}
#pragma clang diagnostic pop
void test_warn_chained_if_stmts_1(int x) {
if (x == 1)
;
else if (x == 1) // expected-warning {{expression is identical to previous condition}}
;
}
void test_warn_chained_if_stmts_2(int x) {
if (x == 1)
;
else if (x == 1) // expected-warning {{expression is identical to previous condition}}
;
else if (x == 1) // expected-warning {{expression is identical to previous condition}}
;
}
void test_warn_chained_if_stmts_3(int x) {
if (x == 1)
;
else if (x == 2)
;
else if (x == 1) // expected-warning {{expression is identical to previous condition}}
;
}
void test_warn_chained_if_stmts_4(int x) {
if (x == 1)
;
else if (func())
;
else if (x == 1) // expected-warning {{expression is identical to previous condition}}
;
}
void test_warn_chained_if_stmts_5(int x) {
if (x & 1)
;
else if (x & 1) // expected-warning {{expression is identical to previous condition}}
;
}
void test_warn_chained_if_stmts_6(int x) {
if (x == 1)
;
else if (x == 2)
;
else if (x == 2) // expected-warning {{expression is identical to previous condition}}
;
else if (x == 3)
;
}
void test_warn_chained_if_stmts_7(int x) {
if (x == 1)
;
else if (x == 2)
;
else if (x == 3)
;
else if (x == 2) // expected-warning {{expression is identical to previous condition}}
;
else if (x == 5)
;
}
void test_warn_chained_if_stmts_8(int x) {
if (x == 1)
;
else if (x == 2)
;
else if (x == 3)
;
else if (x == 2) // expected-warning {{expression is identical to previous condition}}
;
else if (x == 5)
;
else if (x == 3) // expected-warning {{expression is identical to previous condition}}
;
else if (x == 7)
;
}
void test_nowarn_chained_if_stmts_1(int x) {
if (func())
;
else if (func()) // no-warning
;
}
void test_nowarn_chained_if_stmts_2(int x) {
if (func())
;
else if (x == 1)
;
else if (func()) // no-warning
;
}
void test_nowarn_chained_if_stmts_3(int x) {
if (x++)
;
else if (x++) // no-warning
;
}