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Infer @PointerBounds macro from clang __counted_by parameters #77387

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Merged
merged 1 commit into from
Dec 11, 2024
Merged

Infer @PointerBounds macro from clang __counted_by parameters #77387

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4 changes: 4 additions & 0 deletions include/swift/Basic/Features.def
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Original file line number Diff line number Diff line change
Expand Up @@ -406,6 +406,10 @@ EXPERIMENTAL_FEATURE(WarnUnsafe, true)
/// Import unsafe C and C++ constructs as @unsafe.
EXPERIMENTAL_FEATURE(SafeInterop, true)

// Import bounds safety and lifetime attributes from interop headers to
// generate Swift wrappers with safe pointer types.
EXPERIMENTAL_FEATURE(SafeInteropWrappers, false)

/// Ignore resilience errors due to C++ types.
EXPERIMENTAL_FEATURE(AssumeResilientCxxTypes, true)

Expand Down
5 changes: 5 additions & 0 deletions include/swift/Option/Options.td
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Expand Up @@ -792,6 +792,11 @@ def enable_experimental_concise_pound_file : Flag<["-"],
Flags<[FrontendOption, ModuleInterfaceOption]>,
HelpText<"Enable experimental concise '#file' identifier">;

def enable_experimental_bounds_safety_interop :
Flag<["-"], "enable-experimental-bounds-safety-interop">,
Flags<[NoDriverOption, FrontendOption, HelpHidden, ModuleInterfaceOption]>,
HelpText<"Enable experimental C bounds safety interop code generation and config directives">;

def enable_experimental_cxx_interop :
Flag<["-"], "enable-experimental-cxx-interop">,
Flags<[NoDriverOption, FrontendOption, HelpHidden, ModuleInterfaceOption]>,
Expand Down
1 change: 1 addition & 0 deletions lib/AST/FeatureSet.cpp
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Expand Up @@ -321,6 +321,7 @@ static bool usesFeatureAllowUnsafeAttribute(Decl *decl) {

UNINTERESTING_FEATURE(WarnUnsafe)
UNINTERESTING_FEATURE(SafeInterop)
UNINTERESTING_FEATURE(SafeInteropWrappers)
UNINTERESTING_FEATURE(AssumeResilientCxxTypes)
UNINTERESTING_FEATURE(CoroutineAccessorsUnwindOnCallerError)
UNINTERESTING_FEATURE(CoroutineAccessorsAllocateInCallee)
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3 changes: 3 additions & 0 deletions lib/ClangImporter/ClangImporter.cpp
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Expand Up @@ -578,6 +578,9 @@ void importer::getNormalInvocationArguments(
}
}

if (LangOpts.hasFeature(Feature::SafeInteropWrappers))
invocationArgStrs.push_back("-fexperimental-bounds-safety-attributes");

// Set C language options.
if (triple.isOSDarwin()) {
invocationArgStrs.insert(invocationArgStrs.end(), {
Expand Down
194 changes: 134 additions & 60 deletions lib/ClangImporter/ImportDecl.cpp
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Expand Up @@ -108,7 +108,8 @@ createFuncOrAccessor(ClangImporter::Implementation &impl, SourceLoc funcLoc,
std::optional<AccessorInfo> accessorInfo, DeclName name,
SourceLoc nameLoc, GenericParamList *genericParams,
ParameterList *bodyParams, Type resultTy, bool async,
bool throws, DeclContext *dc, ClangNode clangNode) {
bool throws, DeclContext *dc, ClangNode clangNode,
bool hasBoundsAnnotation) {
FuncDecl *decl;
if (accessorInfo) {
decl = AccessorDecl::create(
Expand All @@ -124,6 +125,9 @@ createFuncOrAccessor(ClangImporter::Implementation &impl, SourceLoc funcLoc,
genericParams, dc, clangNode);
}
impl.importSwiftAttrAttributes(decl);
if (hasBoundsAnnotation)
impl.importBoundsAttributes(decl);

return decl;
}

Expand Down Expand Up @@ -3272,7 +3276,8 @@ namespace {
}
return Impl.importFunctionParameterList(
dc, decl, nonSelfParams, decl->isVariadic(), allowNSUIntegerAsInt,
argNames, genericParams, /*resultType=*/nullptr);
argNames, genericParams, /*resultType=*/nullptr,
/*hasBoundsAnnotatedParam=*/nullptr);
}

Decl *
Expand Down Expand Up @@ -3690,6 +3695,7 @@ namespace {

bool importFuncWithoutSignature =
isa<clang::CXXMethodDecl>(decl) && Impl.importSymbolicCXXDecls;
bool hasBoundsAnnotation = false;
if (!dc->isModuleScopeContext() && !isa<clang::CXXMethodDecl>(decl)) {
// Handle initializers.
if (name.getBaseName().isConstructor()) {
Expand Down Expand Up @@ -3786,7 +3792,7 @@ namespace {
importedType = Impl.importFunctionParamsAndReturnType(
dc, decl, {decl->param_begin(), decl->param_size()},
decl->isVariadic(), isInSystemModule(dc), name, bodyParams,
templateParams);
templateParams, &hasBoundsAnnotation);
}

if (auto *mdecl = dyn_cast<clang::CXXMethodDecl>(decl)) {
Expand Down Expand Up @@ -3853,10 +3859,10 @@ namespace {
auto resultTy = importedType.getType();

FuncDecl *func =
createFuncOrAccessor(Impl, loc, accessorInfo, name,
nameLoc, genericParams, bodyParams, resultTy,
createFuncOrAccessor(Impl, loc, accessorInfo, name, nameLoc,
genericParams, bodyParams, resultTy,
/*async=*/false, /*throws=*/false, dc,
clangNode);
clangNode, hasBoundsAnnotation);
result = func;

if (!dc->isModuleScopeContext()) {
Expand Down Expand Up @@ -4899,12 +4905,14 @@ namespace {
}
}

auto result = createFuncOrAccessor(Impl,
/*funcLoc*/ SourceLoc(), accessorInfo,
importedName.getDeclName(),
/*nameLoc*/ SourceLoc(),
/*genericParams=*/nullptr, bodyParams,
resultTy, async, throws, dc, decl);
bool hasBoundsAnnotation =
false; // currently only implemented for functions
auto result = createFuncOrAccessor(
Impl,
/*funcLoc*/ SourceLoc(), accessorInfo, importedName.getDeclName(),
/*nameLoc*/ SourceLoc(),
/*genericParams=*/nullptr, bodyParams, resultTy, async, throws, dc,
decl, hasBoundsAnnotation);

result->setAccess(decl->isDirectMethod() ? AccessLevel::Public
: getOverridableAccessLevel(dc));
Expand Down Expand Up @@ -6544,7 +6552,8 @@ Decl *SwiftDeclConverter::importGlobalAsInitializer(
} else {
parameterList = Impl.importFunctionParameterList(
dc, decl, {decl->param_begin(), decl->param_end()}, decl->isVariadic(),
allowNSUIntegerAsInt, argNames, /*genericParams=*/{}, /*resultType=*/nullptr);
allowNSUIntegerAsInt, argNames, /*genericParams=*/{},
/*resultType=*/nullptr, /*hasBoundsAnnotatedParam=*/nullptr);
}
if (!parameterList)
return nullptr;
Expand Down Expand Up @@ -8344,6 +8353,53 @@ static bool importAsUnsafe(ClangImporter::Implementation &impl,
return false;
}

void ClangImporter::Implementation::importNontrivialAttribute(
Decl *MappedDecl, llvm::StringRef AttrString) {
bool cached = true;
while (true) {
// Dig out a source file we can use for parsing.
auto &sourceFile = getClangSwiftAttrSourceFile(
*MappedDecl->getDeclContext()->getParentModule(), AttrString, cached);

auto topLevelDecls = sourceFile.getTopLevelDecls();

// If we're using the cached version, check whether we can correctly
// clone the attribute.
if (cached) {
bool hasNonclonableAttribute = false;
for (auto decl : topLevelDecls) {
if (hasNonclonableAttribute)
break;

for (auto attr : decl->getAttrs()) {
if (!attr->canClone()) {
hasNonclonableAttribute = true;
break;
}
}
}

// We cannot clone one of the attributes. Go back and build a new
// source file without caching it.
if (hasNonclonableAttribute) {
cached = false;
continue;
}
}

// Collect the attributes from the synthesized top-level declaration in
// the source file. If we're using a cached copy, clone the attribute.
for (auto decl : topLevelDecls) {
SmallVector<DeclAttribute *, 2> attrs(decl->getAttrs().begin(),
decl->getAttrs().end());
for (auto attr : attrs) {
MappedDecl->getAttrs().add(cached ? attr->clone(SwiftContext) : attr);
}
}
break;
}
}

void
ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
auto ClangDecl =
Expand Down Expand Up @@ -8481,53 +8537,7 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
continue;
}

bool cached = true;
while (true) {
// Dig out a source file we can use for parsing.
auto &sourceFile = getClangSwiftAttrSourceFile(
*MappedDecl->getDeclContext()->getParentModule(),
swiftAttr->getAttribute(),
cached);

auto topLevelDecls = sourceFile.getTopLevelDecls();

// If we're using the cached version, check whether we can correctly
// clone the attribute.
if (cached) {
bool hasNonclonableAttribute = false;
for (auto decl : topLevelDecls) {
if (hasNonclonableAttribute)
break;

for (auto attr : decl->getAttrs()) {
if (!attr->canClone()) {
hasNonclonableAttribute = true;
break;
}
}
}

// We cannot clone one of the attributes. Go back and build a new
// source file without caching it.
if (hasNonclonableAttribute) {
cached = false;
continue;
}
}

// Collect the attributes from the synthesized top-level declaration in
// the source file. If we're using a cached copy, clone the attribute.
for (auto decl : topLevelDecls) {
SmallVector<DeclAttribute *, 2> attrs(decl->getAttrs().begin(),
decl->getAttrs().end());
for (auto attr : attrs) {
MappedDecl->getAttrs().add(cached ? attr->clone(SwiftContext)
: attr);
}
}

break;
}
importNontrivialAttribute(MappedDecl, swiftAttr->getAttribute());
}

if (seenUnsafe || importAsUnsafe(*this, ClangDecl, MappedDecl)) {
Expand Down Expand Up @@ -8613,6 +8623,70 @@ ClangImporter::Implementation::importSwiftAttrAttributes(Decl *MappedDecl) {
}
}

namespace {
class PointerParamInfoPrinter {
public:
clang::ASTContext &ctx;
llvm::raw_ostream &out;
bool firstParam = true;
PointerParamInfoPrinter(clang::ASTContext &ctx, llvm::raw_ostream &out)
: ctx(ctx), out(out) {
out << "@PointerBounds(";
}
~PointerParamInfoPrinter() { out << ")"; }

void printCountedBy(const clang::CountAttributedType *CAT,
size_t pointerIndex) {
if (!firstParam) {
out << ", ";
} else {
firstParam = false;
}
clang::Expr *countExpr = CAT->getCountExpr();
bool isSizedBy = CAT->isCountInBytes();
out << ".";
if (isSizedBy)
out << "sizedBy";
else
out << "countedBy";
out << "(pointer: " << pointerIndex + 1 << ", ";
if (isSizedBy)
out << "size";
else
out << "count";
out << ": \"";
countExpr->printPretty(
out, {}, {ctx.getLangOpts()}); // TODO: map clang::Expr to Swift Expr
out << "\")";
}
};
} // namespace

void ClangImporter::Implementation::importBoundsAttributes(
FuncDecl *MappedDecl) {
assert(SwiftContext.LangOpts.hasFeature(Feature::SafeInteropWrappers));
auto ClangDecl =
dyn_cast_or_null<clang::FunctionDecl>(MappedDecl->getClangDecl());
// any function with safe pointer imports should have a clang decl
assert(ClangDecl);
if (!ClangDecl)
return;

llvm::SmallString<128> MacroString;
{
llvm::raw_svector_ostream out(MacroString);

PointerParamInfoPrinter printer(getClangASTContext(), out);
for (auto [index, param] : llvm::enumerate(ClangDecl->parameters())) {
if (auto CAT = param->getType()->getAs<clang::CountAttributedType>()) {
printer.printCountedBy(CAT, index);
}
}
}

importNontrivialAttribute(MappedDecl, MacroString);
}

static bool isUsingMacroName(clang::SourceManager &SM,
clang::SourceLocation loc,
StringRef MacroName) {
Expand Down
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