mirror of
https://github.com/FEX-Emu/FEX.git
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807 lines
35 KiB
C++
807 lines
35 KiB
C++
#include "clang/AST/RecursiveASTVisitor.h"
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#include "clang/Frontend/CompilerInstance.h"
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#include <fstream>
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#include <numeric>
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#include <iostream>
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#include <string_view>
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#include <unordered_map>
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#include <unordered_set>
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#include <fmt/format.h>
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#include <fmt/ostream.h>
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#include <openssl/sha.h>
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#include "interface.h"
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struct FunctionParams {
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std::vector<clang::QualType> param_types;
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};
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struct ThunkedCallback : FunctionParams {
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clang::QualType return_type;
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bool is_stub = false; // Callback will be replaced by a stub that calls std::abort
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bool is_guest = false; // Callback will never be called on the host
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bool is_variadic = false;
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};
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/**
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* Guest<->Host transition point.
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*
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* These are normally used to translate the public API of the guest to host
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* function calls (ThunkedAPIFunction), but a thunk library may also define
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* internal thunks that don't correspond to any function in the implemented
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* API.
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*/
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struct ThunkedFunction : FunctionParams {
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std::string function_name;
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clang::QualType return_type;
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// If true, param_types contains an extra size_t and the valist for marshalling through an internal function
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bool is_variadic = false;
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// If true, the unpacking function will call a custom fexfn_impl function
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// to be provided manually instead of calling the host library function
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// directly.
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// This is implied e.g. for thunks generated for variadic functions
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bool custom_host_impl = false;
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std::string GetOriginalFunctionName() const {
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const std::string suffix = "_internal";
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assert(function_name.length() > suffix.size());
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assert((std::string_view { &*function_name.end() - suffix.size(), suffix.size() } == suffix));
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return function_name.substr(0, function_name.size() - suffix.size());
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}
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// Maps parameter index to ThunkedCallback
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std::unordered_map<unsigned, ThunkedCallback> callbacks;
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clang::FunctionDecl* decl;
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};
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/**
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* Function that is part of the API of the thunked library.
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*
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* For each of these, there is:
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* - A publicly visible guest entrypoint (usually auto-generated but may be manually defined)
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* - A pointer to the native host library function loaded through dlsym (or a user-provided function specified via host_loader)
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* - A ThunkedFunction with the same function_name (possibly suffixed with _internal)
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*/
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struct ThunkedAPIFunction : FunctionParams {
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std::string function_name;
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clang::QualType return_type;
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// name of the function to load the native host symbol with
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std::string host_loader;
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// If true, no guest-side implementation of this function will be autogenerated
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bool custom_guest_impl;
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bool is_variadic;
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// Index of the symbol table to store this export in (see guest_symtables).
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// If empty, a library export is created, otherwise the function is entered into a function pointer array
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std::optional<std::size_t> symtable_namespace;
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};
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struct NamespaceInfo {
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clang::DeclContext* context;
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std::string name;
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// Function to load native host library functions with.
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// This function must be defined manually with the signature "void* func(void*, const char*)"
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std::string host_loader;
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bool generate_guest_symtable;
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bool indirect_guest_calls;
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};
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static std::vector<clang::DeclContext*> decl_contexts;
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struct ClangDiagnosticAsException {
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std::pair<clang::SourceLocation, unsigned> diagnostic;
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void Report(clang::DiagnosticsEngine& diagnostics) const {
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diagnostics.Report(diagnostic.first, diagnostic.second);
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}
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};
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// Helper class to build a custom DiagID from the given message and store it in a throwable object
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struct ErrorReporter {
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clang::ASTContext& context;
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template<std::size_t N>
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[[nodiscard]] ClangDiagnosticAsException operator()(clang::SourceLocation loc, const char (&message)[N]) {
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auto id = context.getDiagnostics().getCustomDiagID(clang::DiagnosticsEngine::Error, message);
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return { std::pair(loc, id) };
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}
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};
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struct NamespaceAnnotations {
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std::optional<unsigned> version;
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std::optional<std::string> load_host_endpoint_via;
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bool generate_guest_symtable = false;
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bool indirect_guest_calls = false;
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};
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static NamespaceAnnotations GetNamespaceAnnotations(clang::ASTContext& context, clang::CXXRecordDecl* decl) {
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if (!decl->hasDefinition()) {
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return {};
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}
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ErrorReporter report_error { context };
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NamespaceAnnotations ret;
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for (const clang::CXXBaseSpecifier& base : decl->bases()) {
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auto annotation = base.getType().getAsString();
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if (annotation == "fexgen::generate_guest_symtable") {
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ret.generate_guest_symtable = true;
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} else if (annotation == "fexgen::indirect_guest_calls") {
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ret.indirect_guest_calls = true;
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} else {
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throw report_error(base.getSourceRange().getBegin(), "Unknown namespace annotation");
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}
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}
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for (const clang::FieldDecl* field : decl->fields()) {
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auto name = field->getNameAsString();
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if (name == "load_host_endpoint_via") {
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auto loader_function_expr = field->getInClassInitializer()->IgnoreCasts();
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auto loader_function_str = llvm::dyn_cast_or_null<clang::StringLiteral>(loader_function_expr);
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if (loader_function_expr && !loader_function_str) {
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throw report_error(loader_function_expr->getBeginLoc(),
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"Must initialize load_host_endpoint_via with a string");
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}
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if (loader_function_str) {
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ret.load_host_endpoint_via = loader_function_str->getString();
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}
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} else if (name == "version") {
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auto initializer = field->getInClassInitializer()->IgnoreCasts();
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auto version_literal = llvm::dyn_cast_or_null<clang::IntegerLiteral>(initializer);
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if (!initializer || !version_literal) {
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throw report_error(field->getBeginLoc(), "No version given (expected integral typed member, e.g. \"int version = 5;\")");
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}
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ret.version = version_literal->getValue().getZExtValue();
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} else {
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throw report_error(field->getBeginLoc(), "Unknown namespace annotation");
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}
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}
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return ret;
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}
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enum class CallbackStrategy {
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Default,
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Stub,
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Guest,
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};
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struct Annotations {
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bool custom_host_impl = false;
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bool custom_guest_entrypoint = false;
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bool returns_guest_pointer = false;
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std::optional<clang::QualType> uniform_va_type;
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CallbackStrategy callback_strategy = CallbackStrategy::Default;
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};
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static Annotations GetAnnotations(clang::ASTContext& context, clang::CXXRecordDecl* decl) {
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ErrorReporter report_error { context };
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Annotations ret;
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for (const auto& base : decl->bases()) {
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auto annotation = base.getType().getAsString();
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if (annotation == "fexgen::returns_guest_pointer") {
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ret.returns_guest_pointer = true;
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} else if (annotation == "fexgen::custom_host_impl") {
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ret.custom_host_impl = true;
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} else if (annotation == "fexgen::callback_stub") {
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ret.callback_strategy = CallbackStrategy::Stub;
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} else if (annotation == "fexgen::callback_guest") {
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ret.callback_strategy = CallbackStrategy::Guest;
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} else if (annotation == "fexgen::custom_guest_entrypoint") {
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ret.custom_guest_entrypoint = true;
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} else {
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throw report_error(base.getSourceRange().getBegin(), "Unknown annotation");
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}
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}
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for (const auto& child_decl : decl->getPrimaryContext()->decls()) {
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if (auto field = llvm::dyn_cast_or_null<clang::FieldDecl>(child_decl)) {
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throw report_error(field->getBeginLoc(), "Unknown field annotation");
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} else if (auto type_alias = llvm::dyn_cast_or_null<clang::TypedefNameDecl>(child_decl)) {
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auto name = type_alias->getNameAsString();
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if (name == "uniform_va_type") {
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ret.uniform_va_type = type_alias->getUnderlyingType();
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} else {
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throw report_error(type_alias->getBeginLoc(), "Unknown type alias annotation");
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}
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}
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}
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return ret;
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}
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class ASTVisitor : public clang::RecursiveASTVisitor<ASTVisitor> {
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public:
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/**
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* Matches "template<auto> struct fex_gen_config { ... }"
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*/
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bool VisitClassTemplateDecl(clang::ClassTemplateDecl* decl) {
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if (decl->getName() != "fex_gen_config") {
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return true;
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}
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if (llvm::dyn_cast<clang::NamespaceDecl>(decl->getDeclContext())) {
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decl_contexts.push_back(decl->getDeclContext());
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}
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return true;
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}
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};
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class ASTConsumer : public clang::ASTConsumer {
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public:
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void HandleTranslationUnit(clang::ASTContext& context) override {
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ASTVisitor{}.TraverseDecl(context.getTranslationUnitDecl());
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}
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};
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class GenerateThunkLibsAction : public clang::ASTFrontendAction {
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public:
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GenerateThunkLibsAction(const std::string& libname, const OutputFilenames&);
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void ExecuteAction() override;
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std::unique_ptr<clang::ASTConsumer> CreateASTConsumer(clang::CompilerInstance&, clang::StringRef /*file*/) override;
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private:
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// Build the internal API representation by processing fex_gen_config and other annotated entities
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void ParseInterface(clang::ASTContext&);
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// Generate helper code for thunk libraries and write them to the output file
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void EmitOutput();
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const std::string& libfilename;
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std::string libname; // sanitized filename, usable as part of emitted function names
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const OutputFilenames& output_filenames;
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std::vector<ThunkedFunction> thunks;
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std::vector<ThunkedAPIFunction> thunked_api;
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std::unordered_set<const clang::Type*> funcptr_types;
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std::optional<unsigned> lib_version;
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std::vector<NamespaceInfo> namespaces;
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};
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GenerateThunkLibsAction::GenerateThunkLibsAction(const std::string& libname_, const OutputFilenames& output_filenames_)
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: libfilename(libname_), libname(libname_), output_filenames(output_filenames_) {
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for (auto& c : libname) {
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if (c == '-') {
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c = '_';
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}
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}
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decl_contexts.clear();
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decl_contexts.push_back(nullptr); // global namespace (replaced by getTranslationUnitDecl later)
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}
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template<typename Fn>
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static std::string format_function_args(const FunctionParams& params, Fn&& format_arg) {
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std::string ret;
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for (std::size_t idx = 0; idx < params.param_types.size(); ++idx) {
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ret += std::forward<Fn>(format_arg)(idx) + ", ";
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}
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// drop trailing ", "
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ret.resize(ret.size() > 2 ? ret.size() - 2 : 0);
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return ret;
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};
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static clang::ClassTemplateDecl*
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FindClassTemplateDeclByName(clang::DeclContext& decl_context, std::string_view symbol_name) {
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auto& ast_context = decl_context.getParentASTContext();
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auto* ident = &ast_context.Idents.get(symbol_name);
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auto declname = ast_context.DeclarationNames.getIdentifier(ident);
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auto result = decl_context.noload_lookup(declname);
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if (result.empty()) {
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return nullptr;
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} else if (std::next(result.begin()) == result.end()) {
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return llvm::dyn_cast<clang::ClassTemplateDecl>(*result.begin());
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} else {
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throw std::runtime_error("Found multiple matches to symbol " + std::string { symbol_name });
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}
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}
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void GenerateThunkLibsAction::ExecuteAction() {
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clang::ASTFrontendAction::ExecuteAction();
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// Post-processing happens here rather than in an overridden EndSourceFileAction implementation.
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// We can't move the logic to the latter since this code might still raise errors, but
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// clang's diagnostics engine is already shut down by the time EndSourceFileAction is called.
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auto& context = getCompilerInstance().getASTContext();
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if (context.getDiagnostics().hasErrorOccurred()) {
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return;
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}
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decl_contexts.front() = context.getTranslationUnitDecl();
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try {
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ParseInterface(context);
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EmitOutput();
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} catch (ClangDiagnosticAsException& exception) {
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exception.Report(context.getDiagnostics());
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}
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}
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void GenerateThunkLibsAction::ParseInterface(clang::ASTContext& context) {
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ErrorReporter report_error { context };
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if (auto template_decl = FindClassTemplateDeclByName(*context.getTranslationUnitDecl(), "fex_gen_type")) {
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for (auto* decl : template_decl->specializations()) {
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const auto& template_args = decl->getTemplateArgs();
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assert(template_args.size() == 1);
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// NOTE: Function types that are equivalent but use differently
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// named types (e.g. GLuint/GLenum) are represented by
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// different Type instances. The canonical type they refer
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// to is unique, however.
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auto type = context.getCanonicalType(template_args[0].getAsType()).getTypePtr();
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funcptr_types.insert(type);
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}
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}
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// Process declarations and specializations of fex_gen_config,
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// i.e. the function descriptions of the thunked API
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for (auto& decl_context : decl_contexts) {
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if (const auto template_decl = FindClassTemplateDeclByName(*decl_context, "fex_gen_config")) {
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// Gather general information about symbols in this namespace
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const auto annotations = GetNamespaceAnnotations(context, template_decl->getTemplatedDecl());
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auto namespace_decl = llvm::dyn_cast<clang::NamespaceDecl>(decl_context);
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namespaces.push_back({ namespace_decl,
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namespace_decl ? namespace_decl->getNameAsString() : "",
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annotations.load_host_endpoint_via.value_or(""),
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annotations.generate_guest_symtable,
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annotations.indirect_guest_calls });
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const auto namespace_idx = namespaces.size() - 1;
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const NamespaceInfo& namespace_info = namespaces.back();
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if (annotations.version) {
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if (namespace_decl) {
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throw report_error(template_decl->getBeginLoc(), "Library version must be defined in the global namespace");
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}
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lib_version = annotations.version;
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}
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// Process specializations of template fex_gen_config
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for (auto* decl : template_decl->specializations()) {
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if (decl->getSpecializationKind() == clang::TSK_ExplicitInstantiationDefinition) {
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throw report_error(decl->getBeginLoc(), "fex_gen_config may not be partially specialized\n");
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}
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const auto& template_args = decl->getTemplateArgs();
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assert(template_args.size() == 1);
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auto emitted_function = llvm::dyn_cast<clang::FunctionDecl>(template_args[0].getAsDecl());
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assert(emitted_function && "Argument is not a function");
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auto return_type = emitted_function->getReturnType();
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const auto annotations = GetAnnotations(context, decl);
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if (return_type->isFunctionPointerType() && !annotations.returns_guest_pointer) {
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throw report_error( decl->getBeginLoc(),
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"Function pointer return types require explicit annotation\n");
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}
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// TODO: Use the types as written in the signature instead?
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ThunkedFunction data;
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data.function_name = emitted_function->getName().str();
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data.return_type = return_type;
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data.is_variadic = emitted_function->isVariadic();
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data.decl = emitted_function;
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data.custom_host_impl = annotations.custom_host_impl;
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for (std::size_t param_idx = 0; param_idx < emitted_function->param_size(); ++param_idx) {
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auto* param = emitted_function->getParamDecl(param_idx);
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data.param_types.push_back(param->getType());
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if (param->getType()->isFunctionPointerType()) {
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auto funcptr = param->getFunctionType()->getAs<clang::FunctionProtoType>();
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ThunkedCallback callback;
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callback.return_type = funcptr->getReturnType();
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for (auto& cb_param : funcptr->getParamTypes()) {
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callback.param_types.push_back(cb_param);
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}
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callback.is_stub = annotations.callback_strategy == CallbackStrategy::Stub;
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callback.is_guest = annotations.callback_strategy == CallbackStrategy::Guest;
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callback.is_variadic = funcptr->isVariadic();
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if (callback.is_guest && !data.custom_host_impl) {
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throw report_error(decl->getBeginLoc(), "callback_guest can only be used with custom_host_impl");
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}
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data.callbacks.emplace(param_idx, callback);
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if (!callback.is_stub && !callback.is_guest) {
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funcptr_types.insert(context.getCanonicalType(funcptr));
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}
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if (data.callbacks.size() != 1) {
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throw report_error(decl->getBeginLoc(), "Support for more than one callback is untested");
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}
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if (funcptr->isVariadic() && !callback.is_stub) {
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throw report_error(decl->getBeginLoc(), "Variadic callbacks are not supported");
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}
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}
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}
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thunked_api.push_back(ThunkedAPIFunction { (const FunctionParams&)data, data.function_name, data.return_type,
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namespace_info.host_loader.empty() ? "dlsym_default" : namespace_info.host_loader,
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data.is_variadic || annotations.custom_guest_entrypoint,
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data.is_variadic,
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std::nullopt });
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if (namespace_info.generate_guest_symtable) {
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thunked_api.back().symtable_namespace = namespace_idx;
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}
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if (data.is_variadic) {
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if (!annotations.uniform_va_type) {
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throw report_error(decl->getBeginLoc(), "Variadic functions must be annotated with parameter type using uniform_va_type");
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}
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// Convert variadic argument list into a count + pointer pair
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data.param_types.push_back(context.getSizeType());
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data.param_types.push_back(context.getPointerType(*annotations.uniform_va_type));
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}
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if (data.is_variadic) {
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// This function is thunked through an "_internal" symbol since its signature
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// is different from the one in the native host/guest libraries.
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data.function_name = data.function_name + "_internal";
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if (data.custom_host_impl) {
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throw report_error(decl->getBeginLoc(), "Custom host impl requested but this is implied by the function signature already");
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}
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data.custom_host_impl = true;
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}
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// For indirect calls, register the function signature as a function pointer type
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if (namespace_info.indirect_guest_calls) {
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funcptr_types.insert(context.getCanonicalType(emitted_function->getFunctionType()));
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}
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thunks.push_back(std::move(data));
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}
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}
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}
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}
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|
|
|
void GenerateThunkLibsAction::EmitOutput() {
|
|
static auto format_decl = [](clang::QualType type, const std::string_view& name) {
|
|
clang::QualType innermostPointee = type;
|
|
while (innermostPointee->isPointerType()) {
|
|
innermostPointee = innermostPointee->getPointeeType();
|
|
}
|
|
if (innermostPointee->isFunctionType()) {
|
|
// Function pointer declarations (e.g. void (**callback)()) require
|
|
// the variable name to be prefixed *and* suffixed.
|
|
|
|
auto signature = type.getAsString();
|
|
|
|
// Search for strings like (*), (**), or (*****). Insert the
|
|
// variable name before the closing parenthesis
|
|
auto needle = signature.begin();
|
|
for (; needle != signature.end(); ++needle) {
|
|
if (signature.end() - needle < 3 ||
|
|
std::string_view { &*needle, 2 } != "(*") {
|
|
continue;
|
|
}
|
|
while (*++needle == '*') {
|
|
}
|
|
if (*needle == ')') {
|
|
break;
|
|
}
|
|
}
|
|
if (needle == signature.end()) {
|
|
// It's *probably* a typedef, so this should be safe after all
|
|
return fmt::format("{} {}", signature, name);
|
|
} else {
|
|
signature.insert(needle, name.begin(), name.end());
|
|
return signature;
|
|
}
|
|
} else {
|
|
return type.getAsString() + " " + std::string(name);
|
|
}
|
|
};
|
|
|
|
auto format_struct_members = [](const FunctionParams& params, const char* indent) {
|
|
std::string ret;
|
|
for (std::size_t idx = 0; idx < params.param_types.size(); ++idx) {
|
|
ret += indent + format_decl(params.param_types[idx].getUnqualifiedType(), fmt::format("a_{}", idx)) + ";\n";
|
|
}
|
|
return ret;
|
|
};
|
|
|
|
auto format_function_params = [](const FunctionParams& params) {
|
|
std::string ret;
|
|
for (std::size_t idx = 0; idx < params.param_types.size(); ++idx) {
|
|
auto& type = params.param_types[idx];
|
|
ret += format_decl(type, fmt::format("a_{}", idx)) + ", ";
|
|
}
|
|
// drop trailing ", "
|
|
ret.resize(ret.size() > 2 ? ret.size() - 2 : 0);
|
|
return ret;
|
|
};
|
|
|
|
auto get_sha256 = [this](const std::string& function_name) {
|
|
std::string sha256_message = libname + ":" + function_name;
|
|
std::vector<unsigned char> sha256(SHA256_DIGEST_LENGTH);
|
|
SHA256(reinterpret_cast<const unsigned char*>(sha256_message.data()),
|
|
sha256_message.size(),
|
|
sha256.data());
|
|
return sha256;
|
|
};
|
|
|
|
auto get_callback_name = [](std::string_view function_name, unsigned param_index) -> std::string {
|
|
return fmt::format("{}CBFN{}", function_name, param_index);
|
|
};
|
|
|
|
// Files used guest-side
|
|
if (!output_filenames.guest.empty()) {
|
|
std::ofstream file(output_filenames.guest);
|
|
|
|
// Guest->Host transition points for API functions
|
|
file << "extern \"C\" {\n";
|
|
for (auto& thunk : thunks) {
|
|
const auto& function_name = thunk.function_name;
|
|
auto sha256 = get_sha256(function_name);
|
|
fmt::print( file, "MAKE_THUNK({}, {}, \"{:#02x}\")\n",
|
|
libname, function_name, fmt::join(sha256, ", "));
|
|
}
|
|
file << "}\n";
|
|
|
|
// Guest->Host transition points for invoking runtime host-function pointers based on their signature
|
|
for (auto type_it = funcptr_types.begin(); type_it != funcptr_types.end(); ++type_it) {
|
|
auto* type = *type_it;
|
|
std::string funcptr_signature = clang::QualType { type, 0 }.getAsString();
|
|
|
|
auto cb_sha256 = get_sha256("fexcallback_" + funcptr_signature);
|
|
|
|
// Thunk used for guest-side calls to host function pointers
|
|
file << " // " << funcptr_signature << "\n";
|
|
auto funcptr_idx = std::distance(funcptr_types.begin(), type_it);
|
|
fmt::print( file, " MAKE_CALLBACK_THUNK(callback_{}, {}, \"{:#02x}\");\n",
|
|
funcptr_idx, funcptr_signature, fmt::join(cb_sha256, ", "));
|
|
}
|
|
|
|
// Thunks-internal packing functions
|
|
file << "extern \"C\" {\n";
|
|
for (auto& data : thunks) {
|
|
const auto& function_name = data.function_name;
|
|
bool is_void = data.return_type->isVoidType();
|
|
file << "FEX_PACKFN_LINKAGE auto fexfn_pack_" << function_name << "(";
|
|
for (std::size_t idx = 0; idx < data.param_types.size(); ++idx) {
|
|
auto& type = data.param_types[idx];
|
|
file << (idx == 0 ? "" : ", ") << format_decl(type, fmt::format("a_{}", idx));
|
|
}
|
|
// Using trailing return type as it makes handling function pointer returns much easier
|
|
file << ") -> " << data.return_type.getAsString() << " {\n";
|
|
file << " struct {\n";
|
|
for (std::size_t idx = 0; idx < data.param_types.size(); ++idx) {
|
|
auto& type = data.param_types[idx];
|
|
file << " " << format_decl(type.getUnqualifiedType(), fmt::format("a_{}", idx)) << ";\n";
|
|
}
|
|
if (!is_void) {
|
|
file << " " << format_decl(data.return_type, "rv") << ";\n";
|
|
} else if (data.param_types.size() == 0) {
|
|
// Avoid "empty struct has size 0 in C, size 1 in C++" warning
|
|
file << " char force_nonempty;\n";
|
|
}
|
|
file << " } args;\n";
|
|
|
|
for (std::size_t idx = 0; idx < data.param_types.size(); ++idx) {
|
|
auto cb = data.callbacks.find(idx);
|
|
|
|
file << " args.a_" << idx << " = ";
|
|
if (cb == data.callbacks.end() || cb->second.is_stub || cb->second.is_guest) {
|
|
file << "a_" << idx << ";\n";
|
|
} else {
|
|
// Before passing guest function pointers to the host, wrap them in a host-callable trampoline
|
|
fmt::print(file, "AllocateHostTrampolineForGuestFunction(a_{});\n", idx);
|
|
}
|
|
}
|
|
file << " fexthunks_" << libname << "_" << function_name << "(&args);\n";
|
|
if (!is_void) {
|
|
file << " return args.rv;\n";
|
|
}
|
|
file << "}\n";
|
|
}
|
|
file << "}\n";
|
|
|
|
// Publicly exports equivalent to symbols exported from the native guest library
|
|
file << "extern \"C\" {\n";
|
|
for (auto& data : thunked_api) {
|
|
if (data.custom_guest_impl) {
|
|
continue;
|
|
}
|
|
|
|
const auto& function_name = data.function_name;
|
|
|
|
file << "__attribute__((alias(\"fexfn_pack_" << function_name << "\"))) auto " << function_name << "(";
|
|
for (std::size_t idx = 0; idx < data.param_types.size(); ++idx) {
|
|
auto& type = data.param_types[idx];
|
|
file << (idx == 0 ? "" : ", ") << format_decl(type, "a_" + std::to_string(idx));
|
|
}
|
|
file << ") -> " << data.return_type.getAsString() << ";\n";
|
|
}
|
|
file << "}\n";
|
|
|
|
// Symbol enumerators
|
|
for (std::size_t namespace_idx = 0; namespace_idx < namespaces.size(); ++namespace_idx) {
|
|
const auto& ns = namespaces[namespace_idx];
|
|
file << "#define FOREACH_" << ns.name << (ns.name.empty() ? "" : "_") << "SYMBOL(EXPAND) \\\n";
|
|
for (auto& symbol : thunked_api) {
|
|
if (symbol.symtable_namespace.value_or(0) == namespace_idx) {
|
|
file << " EXPAND(" << symbol.function_name << ", \"TODO\") \\\n";
|
|
}
|
|
}
|
|
file << "\n";
|
|
}
|
|
}
|
|
|
|
// Files used host-side
|
|
if (!output_filenames.host.empty()) {
|
|
std::ofstream file(output_filenames.host);
|
|
|
|
// Forward declarations for symbols loaded from the native host library
|
|
for (auto& import : thunked_api) {
|
|
const auto& function_name = import.function_name;
|
|
const char* variadic_ellipsis = import.is_variadic ? ", ..." : "";
|
|
file << "using fexldr_type_" << libname << "_" << function_name << " = auto " << "(" << format_function_params(import) << variadic_ellipsis << ") -> " << import.return_type.getAsString() << ";\n";
|
|
file << "static fexldr_type_" << libname << "_" << function_name << " *fexldr_ptr_" << libname << "_" << function_name << ";\n";
|
|
}
|
|
|
|
file << "extern \"C\" {\n";
|
|
for (auto& thunk : thunks) {
|
|
const auto& function_name = thunk.function_name;
|
|
|
|
// Generate stub callbacks
|
|
for (auto& [cb_idx, cb] : thunk.callbacks) {
|
|
if (cb.is_stub) {
|
|
const char* variadic_ellipsis = cb.is_variadic ? ", ..." : "";
|
|
auto cb_function_name = "fexfn_unpack_" + get_callback_name(function_name, cb_idx) + "_stub";
|
|
file << "[[noreturn]] static " << cb.return_type.getAsString() << " "
|
|
<< cb_function_name << "("
|
|
<< format_function_params(cb) << variadic_ellipsis << ") {\n";
|
|
file << " fprintf(stderr, \"FATAL: Attempted to invoke callback stub for " << function_name << "\\n\");\n";
|
|
file << " std::abort();\n";
|
|
file << "}\n";
|
|
}
|
|
}
|
|
|
|
// Forward declarations for user-provided implementations
|
|
if (thunk.custom_host_impl) {
|
|
file << "static auto fexfn_impl_" << libname << "_" << function_name << "(";
|
|
for (std::size_t idx = 0; idx < thunk.param_types.size(); ++idx) {
|
|
// TODO: fex_guest_function_ptr for guest callbacks?
|
|
auto& type = thunk.param_types[idx];
|
|
|
|
file << (idx == 0 ? "" : ", ");
|
|
|
|
auto cb = thunk.callbacks.find(idx);
|
|
if (cb != thunk.callbacks.end() && cb->second.is_guest) {
|
|
file << "fex_guest_function_ptr a_" << idx;
|
|
} else {
|
|
file << format_decl(type, fmt::format("a_{}", idx));
|
|
}
|
|
}
|
|
// Using trailing return type as it makes handling function pointer returns much easier
|
|
file << ") -> " << thunk.return_type.getAsString() << ";\n";
|
|
}
|
|
|
|
// Packed argument structs used in fexfn_unpack_*
|
|
auto GeneratePackedArgs = [&](const auto &function_name, const auto &thunk) -> std::string {
|
|
std::string struct_name = "fexfn_packed_args_" + libname + "_" + function_name;
|
|
file << "struct " << struct_name << " {\n";
|
|
|
|
file << format_struct_members(thunk, " ");
|
|
if (!thunk.return_type->isVoidType()) {
|
|
file << " " << format_decl(thunk.return_type, "rv") << ";\n";
|
|
} else if (thunk.param_types.size() == 0) {
|
|
// Avoid "empty struct has size 0 in C, size 1 in C++" warning
|
|
file << " char force_nonempty;\n";
|
|
}
|
|
file << "};\n";
|
|
return struct_name;
|
|
};
|
|
auto struct_name = GeneratePackedArgs(function_name, thunk);
|
|
|
|
// Unpacking functions
|
|
auto function_to_call = "fexldr_ptr_" + libname + "_" + function_name;
|
|
if (thunk.custom_host_impl) {
|
|
function_to_call = "fexfn_impl_" + libname + "_" + function_name;
|
|
}
|
|
|
|
file << "static void fexfn_unpack_" << libname << "_" << function_name << "(" << struct_name << "* args) {\n";
|
|
file << (thunk.return_type->isVoidType() ? " " : " args->rv = ") << function_to_call << "(";
|
|
{
|
|
auto format_param = [&](std::size_t idx) {
|
|
auto cb = thunk.callbacks.find(idx);
|
|
if (cb != thunk.callbacks.end() && cb->second.is_stub) {
|
|
return "fexfn_unpack_" + get_callback_name(function_name, cb->first) + "_stub";
|
|
} else if (cb != thunk.callbacks.end() && cb->second.is_guest) {
|
|
return fmt::format("fex_guest_function_ptr {{ args->a_{} }}", idx);
|
|
} else if (cb != thunk.callbacks.end()) {
|
|
auto arg_name = fmt::format("args->a_{}", idx);
|
|
// Use comma operator to inject a function call before returning the argument
|
|
return "(FinalizeHostTrampolineForGuestFunction(" + arg_name + "), " + arg_name + ")";
|
|
|
|
} else {
|
|
return fmt::format("args->a_{}", idx);
|
|
}
|
|
};
|
|
|
|
file << format_function_args(thunk, format_param);
|
|
}
|
|
file << ");\n";
|
|
file << "}\n";
|
|
}
|
|
file << "}\n";
|
|
|
|
// Endpoints for Guest->Host invocation of API functions
|
|
file << "static ExportEntry exports[] = {\n";
|
|
for (auto& thunk : thunks) {
|
|
const auto& function_name = thunk.function_name;
|
|
auto sha256 = get_sha256(function_name);
|
|
fmt::print( file, " {{(uint8_t*)\"\\x{:02x}\", (void(*)(void *))&fexfn_unpack_{}_{}}}, // {}:{}\n",
|
|
fmt::join(sha256, "\\x"), libname, function_name, libname, function_name);
|
|
}
|
|
|
|
// Endpoints for Guest->Host invocation of runtime host-function pointers
|
|
for (auto& type : funcptr_types) {
|
|
std::string mangled_name = clang::QualType { type, 0 }.getAsString();
|
|
auto cb_sha256 = get_sha256("fexcallback_" + mangled_name);
|
|
fmt::print( file, " {{(uint8_t*)\"\\x{:02x}\", (void(*)(void *))&CallbackUnpack<{}>::ForIndirectCall}},\n",
|
|
fmt::join(cb_sha256, "\\x"), mangled_name);
|
|
}
|
|
file << " { nullptr, nullptr }\n";
|
|
file << "};\n";
|
|
|
|
// Symbol lookup from native host library
|
|
file << "static void* fexldr_ptr_" << libname << "_so;\n";
|
|
file << "extern \"C\" bool fexldr_init_" << libname << "() {\n";
|
|
|
|
std::string version_suffix;
|
|
if (lib_version) {
|
|
version_suffix = '.' + std::to_string(*lib_version);
|
|
}
|
|
const std::string library_filename = libfilename + ".so" + version_suffix;
|
|
|
|
// Load the host library in the global symbol namespace.
|
|
// This follows how these libraries get loaded in a non-emulated environment,
|
|
// Either by directly linking to the library or a loader (In OpenGL or Vulkan) putting everything in the global namespace.
|
|
file << " fexldr_ptr_" << libname << "_so = dlopen(\"" << library_filename << "\", RTLD_GLOBAL | RTLD_LAZY);\n";
|
|
|
|
file << " if (!fexldr_ptr_" << libname << "_so) { return false; }\n\n";
|
|
for (auto& import : thunked_api) {
|
|
fmt::print( file, " (void*&)fexldr_ptr_{}_{} = {}(fexldr_ptr_{}_so, \"{}\");\n",
|
|
libname, import.function_name, import.host_loader, libname, import.function_name);
|
|
}
|
|
file << " return true;\n";
|
|
file << "}\n";
|
|
}
|
|
}
|
|
|
|
std::unique_ptr<clang::ASTConsumer> GenerateThunkLibsAction::CreateASTConsumer(clang::CompilerInstance&, clang::StringRef) {
|
|
return std::make_unique<ASTConsumer>();
|
|
}
|
|
|
|
std::unique_ptr<clang::FrontendAction> GenerateThunkLibsActionFactory::create() {
|
|
return std::make_unique<GenerateThunkLibsAction>(libname, output_filenames);
|
|
}
|