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// TODO: header template
#include "clang/Analysis/Analyses/OSLog.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/Analysis/Analyses/FormatString.h"
#include "clang/Basic/Builtins.h"
#include "llvm/ADT/SmallBitVector.h"
using namespace clang;
using llvm::APInt;
using clang::analyze_os_log::OSLogBufferItem;
using clang::analyze_os_log::OSLogBufferLayout;
class OSLogFormatStringHandler
: public analyze_format_string::FormatStringHandler {
private:
struct ArgData {
const Expr *E = nullptr;
Optional<OSLogBufferItem::Kind> Kind;
Optional<unsigned> Size;
Optional<const Expr *> Count;
Optional<const Expr *> Precision;
Optional<const Expr *> FieldWidth;
unsigned char Flags = 0;
};
SmallVector<ArgData, 4> ArgsData;
ArrayRef<const Expr *> Args;
OSLogBufferItem::Kind
getKind(analyze_format_string::ConversionSpecifier::Kind K) {
switch (K) {
case clang::analyze_format_string::ConversionSpecifier::sArg: // "%s"
return OSLogBufferItem::StringKind;
case clang::analyze_format_string::ConversionSpecifier::SArg: // "%S"
return OSLogBufferItem::WideStringKind;
case clang::analyze_format_string::ConversionSpecifier::PArg: { // "%P"
return OSLogBufferItem::PointerKind;
case clang::analyze_format_string::ConversionSpecifier::ObjCObjArg: // "%@"
return OSLogBufferItem::ObjCObjKind;
case clang::analyze_format_string::ConversionSpecifier::PrintErrno: // "%m"
return OSLogBufferItem::ErrnoKind;
default:
return OSLogBufferItem::ScalarKind;
}
}
}
public:
OSLogFormatStringHandler(ArrayRef<const Expr *> Args) : Args(Args) {
ArgsData.reserve(Args.size());
}
virtual bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier,
unsigned SpecifierLen) {
if (!FS.consumesDataArgument() &&
FS.getConversionSpecifier().getKind() !=
clang::analyze_format_string::ConversionSpecifier::PrintErrno)
return true;
ArgsData.emplace_back();
unsigned ArgIndex = FS.getArgIndex();
if (ArgIndex < Args.size())
ArgsData.back().E = Args[ArgIndex];
// First get the Kind
ArgsData.back().Kind = getKind(FS.getConversionSpecifier().getKind());
if (ArgsData.back().Kind != OSLogBufferItem::ErrnoKind &&
!ArgsData.back().E) {
// missing argument
ArgsData.pop_back();
return false;
}
switch (FS.getConversionSpecifier().getKind()) {
case clang::analyze_format_string::ConversionSpecifier::sArg: // "%s"
case clang::analyze_format_string::ConversionSpecifier::SArg: { // "%S"
auto &precision = FS.getPrecision();
switch (precision.getHowSpecified()) {
case clang::analyze_format_string::OptionalAmount::NotSpecified: // "%s"
break;
case clang::analyze_format_string::OptionalAmount::Constant: // "%.16s"
ArgsData.back().Size = precision.getConstantAmount();
break;
case clang::analyze_format_string::OptionalAmount::Arg: // "%.*s"
ArgsData.back().Count = Args[precision.getArgIndex()];
break;
case clang::analyze_format_string::OptionalAmount::Invalid:
return false;
}
break;
}
case clang::analyze_format_string::ConversionSpecifier::PArg: { // "%P"
auto &precision = FS.getPrecision();
switch (precision.getHowSpecified()) {
case clang::analyze_format_string::OptionalAmount::NotSpecified: // "%P"
return false; // length must be supplied with pointer format specifier
case clang::analyze_format_string::OptionalAmount::Constant: // "%.16P"
ArgsData.back().Size = precision.getConstantAmount();
break;
case clang::analyze_format_string::OptionalAmount::Arg: // "%.*P"
ArgsData.back().Count = Args[precision.getArgIndex()];
break;
case clang::analyze_format_string::OptionalAmount::Invalid:
return false;
}
break;
}
default:
if (FS.getPrecision().hasDataArgument()) {
ArgsData.back().Precision = Args[FS.getPrecision().getArgIndex()];
}
break;
}
if (FS.getFieldWidth().hasDataArgument()) {
ArgsData.back().FieldWidth = Args[FS.getFieldWidth().getArgIndex()];
}
if (FS.isPrivate()) {
ArgsData.back().Flags |= OSLogBufferItem::IsPrivate;
}
if (FS.isPublic()) {
ArgsData.back().Flags |= OSLogBufferItem::IsPublic;
}
return true;
}
void computeLayout(ASTContext &Ctx, OSLogBufferLayout &Layout) const {
Layout.Items.clear();
for (auto &Data : ArgsData) {
if (Data.FieldWidth) {
CharUnits Size = Ctx.getTypeSizeInChars((*Data.FieldWidth)->getType());
Layout.Items.emplace_back(OSLogBufferItem::ScalarKind, *Data.FieldWidth,
Size, 0);
}
if (Data.Precision) {
CharUnits Size = Ctx.getTypeSizeInChars((*Data.Precision)->getType());
Layout.Items.emplace_back(OSLogBufferItem::ScalarKind, *Data.Precision,
Size, 0);
}
if (Data.Count) {
// "%.*P" has an extra "count" that we insert before the argument.
CharUnits Size = Ctx.getTypeSizeInChars((*Data.Count)->getType());
Layout.Items.emplace_back(OSLogBufferItem::CountKind, *Data.Count, Size,
0);
}
if (Data.Size)
Layout.Items.emplace_back(Ctx, CharUnits::fromQuantity(*Data.Size),
Data.Flags);
if (Data.Kind) {
CharUnits Size;
if (*Data.Kind == OSLogBufferItem::ErrnoKind)
Size = CharUnits::Zero();
else
Size = Ctx.getTypeSizeInChars(Data.E->getType());
Layout.Items.emplace_back(*Data.Kind, Data.E, Size, Data.Flags);
} else {
auto Size = Ctx.getTypeSizeInChars(Data.E->getType());
Layout.Items.emplace_back(OSLogBufferItem::ScalarKind, Data.E, Size,
Data.Flags);
}
}
}
};
bool clang::analyze_os_log::computeOSLogBufferLayout(
ASTContext &Ctx, const CallExpr *E, OSLogBufferLayout &Layout) {
ArrayRef<const Expr *> Args(E->getArgs(), E->getArgs() + E->getNumArgs());
const Expr *StringArg;
ArrayRef<const Expr *> VarArgs;
switch (E->getBuiltinCallee()) {
case Builtin::BI__builtin_os_log_format_buffer_size:
assert(E->getNumArgs() >= 1 &&
"__builtin_os_log_format_buffer_size takes at least 1 argument");
StringArg = E->getArg(0);
VarArgs = Args.slice(1);
break;
case Builtin::BI__builtin_os_log_format:
assert(E->getNumArgs() >= 2 &&
"__builtin_os_log_format takes at least 2 arguments");
StringArg = E->getArg(1);
VarArgs = Args.slice(2);
break;
default:
llvm_unreachable("non-os_log builtin passed to computeOSLogBufferLayout");
}
const StringLiteral *Lit = cast<StringLiteral>(StringArg->IgnoreParenCasts());
assert(Lit && (Lit->isAscii() || Lit->isUTF8()));
StringRef Data = Lit->getString();
OSLogFormatStringHandler H(VarArgs);
ParsePrintfString(H, Data.begin(), Data.end(), Ctx.getLangOpts(),
Ctx.getTargetInfo(), /*isFreeBSDKPrintf*/ false);
H.computeLayout(Ctx, Layout);
return true;
}
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