Added notion of '*' specified format width/specifiers when checking
printf format strings. Added type checking to see if the matching
width/precision argument was of type 'int'.
Thanks to Anders Carlsson for reporting this missing feature.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42933 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Sema/SemaChecking.cpp b/Sema/SemaChecking.cpp
index f764d80..c2e3817 100644
--- a/Sema/SemaChecking.cpp
+++ b/Sema/SemaChecking.cpp
@@ -313,10 +313,47 @@
// Seen '%'. Now processing a format conversion.
switch (Str[StrIdx]) {
- // Handle dynamic precision specifier.
- case '*':
- if (Str[StrIdx-1] == '.') ++numConversions;
+ // Handle dynamic precision or width specifier.
+ case '*': {
+ ++numConversions;
+
+ if (!HasVAListArg && numConversions > numDataArgs) {
+
+ SourceLocation Loc =
+ PP.AdvanceToTokenCharacter(Args[format_idx]->getLocStart(),
+ StrIdx+1);
+
+ if (Str[StrIdx-1] == '.')
+ Diag(Loc, diag::warn_printf_asterisk_precision_missing_arg,
+ Fn->getSourceRange());
+ else
+ Diag(Loc, diag::warn_printf_asterisk_width_missing_arg,
+ Fn->getSourceRange());
+
+ // Don't do any more checking. We'll just emit spurious errors.
+ return;
+ }
+
+ // Perform type checking on width/precision specifier.
+ Expr* E = Args[format_idx+numConversions];
+ QualType T = E->getType().getCanonicalType();
+ if (BuiltinType *BT = dyn_cast<BuiltinType>(T))
+ if (BT->getKind() == BuiltinType::Int)
+ break;
+
+ SourceLocation Loc =
+ PP.AdvanceToTokenCharacter(Args[format_idx]->getLocStart(),
+ StrIdx+1);
+
+ if (Str[StrIdx-1] == '.')
+ Diag(Loc, diag::warn_printf_asterisk_precision_wrong_type,
+ T.getAsString(), E->getSourceRange());
+ else
+ Diag(Loc, diag::warn_printf_asterisk_width_wrong_type,
+ T.getAsString(), E->getSourceRange());
+
break;
+ }
// Characters which can terminate a format conversion
// (e.g. "%d"). Characters that specify length modifiers or
@@ -376,7 +413,7 @@
LastConversionIdx+1);
Diag(Loc, diag::warn_printf_invalid_conversion,
- std::string(Str+LastConversionIdx, Str+StrIdx),
+ std::string(Str+LastConversionIdx, Str+StrIdx),
Fn->getSourceRange());
// This conversion is broken. Advance to the next format
diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 81aaa5c..dec9343 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -789,6 +789,14 @@
"format string should not be a wide string")
DIAG(warn_printf_format_string_contains_null_char, WARNING,
"format string contains '\\0' within the string body")
+DIAG(warn_printf_asterisk_width_missing_arg, WARNING,
+ "'*' specified field width is missing a matching 'int' argument")
+DIAG(warn_printf_asterisk_precision_missing_arg, WARNING,
+ "'.*' specified field precision is missing a matching 'int' argument")
+DIAG(warn_printf_asterisk_width_wrong_type, WARNING,
+ "field width should have type 'int', but argument has type '%0'")
+DIAG(warn_printf_asterisk_precision_wrong_type, WARNING,
+ "field precision should have type 'int', but argument has type '%0'")
// CHECK: returning address/reference of stack memory
DIAG(warn_ret_stack_addr, WARNING,
diff --git a/test/Sema/format-strings.c b/test/Sema/format-strings.c
index 8b3be68..2222f79 100644
--- a/test/Sema/format-strings.c
+++ b/test/Sema/format-strings.c
@@ -61,3 +61,11 @@
printf(L"foo %d",2); // expected-warning {{should not be a wide string}}
vasprintf(&b,L"bar %d",2); // expected-warning {{should not be a wide string}}
}
+
+void check_asterisk_precision_width(int x) {
+ printf("%*d"); // expected-warning {{'*' specified field width is missing a matching 'int' argument}}
+ printf("%.*d"); // expected-warning {{'.*' specified field precision is missing a matching 'int' argument}}
+ printf("%*d",12,x); // no-warning
+ printf("%*d","foo",x); // expected-warning {{field width should have type 'int', but argument has type 'char *'}}
+ printf("%.*d","foo",x); // expected-warning {{field precision should have type 'int', but argument has type 'char *'}}
+}
\ No newline at end of file