Files
clang-p2996/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
Raphael Isemann 2b37c5b560 [lldb][NFC] Make ClangExpressionSourceCode's wrapping logic more consistent
Summary:
ClangExpressionSourceCode has different ways to wrap the user expression based on
which context the expression is executed in. For example, if we're in a C++ member
function we put the expression inside a fake member function of a fake class to make the
evaluation possible. Similar things are done for Objective-C instance/static methods.
There is also a default wrapping where we put the expression in a normal function
just to make it possible to execute it.

The way we currently define which kind of wrapping the expression needs is based on
the `wrapping_language` we keep passing to the ClangExpressionSourceCode
instance. We repurposed the language type enum for that variable to distinguish the
cases above with the following mapping:
* language = C_plus_plus -> member function wrapping
* language = ObjC -> instance/static method wrapping (`is_static` distinguished between those two).
* language = C -> normal function wrapping
* all other cases like C_plus_plus11, Haskell etc. make our class a no-op that does mostly nothing.

That mapping is currently not documented and just confusing as the `language`
is unrelated to the expression language (and in the ClangUserExpression we even pretend
that it *is* the actual language, but luckily never used it for anything). Some of the code
in ClangExpressionSourceCode is also obviously thinking that this is the actual language of
the expression as it checks for non-existent cases such as `ObjC_plus_plus` which is
not part of the mapping.

This patch makes a new enum to describe the four cases above (with instance/static Objective-C
methods now being their own case). It also make that enum just a member of
ClangExpressionSourceCode instead of having to pass the same value to the class repeatedly.
This gets also rid of all the switch-case-checks for 'unknown' language such as C_plus_plus11 as this
is no longer necessary.

Reviewers: labath, JDevlieghere

Reviewed By: labath

Subscribers: abidh

Differential Revision: https://reviews.llvm.org/D80793
2020-06-01 13:24:30 +02:00

476 lines
16 KiB
C++

//===-- ClangExpressionSourceCode.cpp -------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "ClangExpressionSourceCode.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/StringRef.h"
#include "Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.h"
#include "Plugins/ExpressionParser/Clang/ClangPersistentVariables.h"
#include "lldb/Symbol/Block.h"
#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/DebugMacros.h"
#include "lldb/Symbol/TypeSystem.h"
#include "lldb/Symbol/VariableList.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Language.h"
#include "lldb/Target/Platform.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/StreamString.h"
using namespace lldb_private;
#define PREFIX_NAME "<lldb wrapper prefix>"
const llvm::StringRef ClangExpressionSourceCode::g_prefix_file_name = PREFIX_NAME;
const char *ClangExpressionSourceCode::g_expression_prefix =
"#line 1 \"" PREFIX_NAME R"("
#ifndef offsetof
#define offsetof(t, d) __builtin_offsetof(t, d)
#endif
#ifndef NULL
#define NULL (__null)
#endif
#ifndef Nil
#define Nil (__null)
#endif
#ifndef nil
#define nil (__null)
#endif
#ifndef YES
#define YES ((BOOL)1)
#endif
#ifndef NO
#define NO ((BOOL)0)
#endif
typedef __INT8_TYPE__ int8_t;
typedef __UINT8_TYPE__ uint8_t;
typedef __INT16_TYPE__ int16_t;
typedef __UINT16_TYPE__ uint16_t;
typedef __INT32_TYPE__ int32_t;
typedef __UINT32_TYPE__ uint32_t;
typedef __INT64_TYPE__ int64_t;
typedef __UINT64_TYPE__ uint64_t;
typedef __INTPTR_TYPE__ intptr_t;
typedef __UINTPTR_TYPE__ uintptr_t;
typedef __SIZE_TYPE__ size_t;
typedef __PTRDIFF_TYPE__ ptrdiff_t;
typedef unsigned short unichar;
extern "C"
{
int printf(const char * __restrict, ...);
}
)";
namespace {
class AddMacroState {
enum State {
CURRENT_FILE_NOT_YET_PUSHED,
CURRENT_FILE_PUSHED,
CURRENT_FILE_POPPED
};
public:
AddMacroState(const FileSpec &current_file, const uint32_t current_file_line)
: m_state(CURRENT_FILE_NOT_YET_PUSHED), m_current_file(current_file),
m_current_file_line(current_file_line) {}
void StartFile(const FileSpec &file) {
m_file_stack.push_back(file);
if (file == m_current_file)
m_state = CURRENT_FILE_PUSHED;
}
void EndFile() {
if (m_file_stack.size() == 0)
return;
FileSpec old_top = m_file_stack.back();
m_file_stack.pop_back();
if (old_top == m_current_file)
m_state = CURRENT_FILE_POPPED;
}
// An entry is valid if it occurs before the current line in the current
// file.
bool IsValidEntry(uint32_t line) {
switch (m_state) {
case CURRENT_FILE_NOT_YET_PUSHED:
return true;
case CURRENT_FILE_PUSHED:
// If we are in file included in the current file, the entry should be
// added.
if (m_file_stack.back() != m_current_file)
return true;
return line < m_current_file_line;
default:
return false;
}
}
private:
std::vector<FileSpec> m_file_stack;
State m_state;
FileSpec m_current_file;
uint32_t m_current_file_line;
};
} // anonymous namespace
static void AddMacros(const DebugMacros *dm, CompileUnit *comp_unit,
AddMacroState &state, StreamString &stream) {
if (dm == nullptr)
return;
for (size_t i = 0; i < dm->GetNumMacroEntries(); i++) {
const DebugMacroEntry &entry = dm->GetMacroEntryAtIndex(i);
uint32_t line;
switch (entry.GetType()) {
case DebugMacroEntry::DEFINE:
if (state.IsValidEntry(entry.GetLineNumber()))
stream.Printf("#define %s\n", entry.GetMacroString().AsCString());
else
return;
break;
case DebugMacroEntry::UNDEF:
if (state.IsValidEntry(entry.GetLineNumber()))
stream.Printf("#undef %s\n", entry.GetMacroString().AsCString());
else
return;
break;
case DebugMacroEntry::START_FILE:
line = entry.GetLineNumber();
if (state.IsValidEntry(line))
state.StartFile(entry.GetFileSpec(comp_unit));
else
return;
break;
case DebugMacroEntry::END_FILE:
state.EndFile();
break;
case DebugMacroEntry::INDIRECT:
AddMacros(entry.GetIndirectDebugMacros(), comp_unit, state, stream);
break;
default:
// This is an unknown/invalid entry. Ignore.
break;
}
}
}
lldb_private::ClangExpressionSourceCode::ClangExpressionSourceCode(
llvm::StringRef filename, llvm::StringRef name, llvm::StringRef prefix,
llvm::StringRef body, Wrapping wrap, WrapKind wrap_kind)
: ExpressionSourceCode(name, prefix, body, wrap), m_wrap_kind(wrap_kind) {
// Use #line markers to pretend that we have a single-line source file
// containing only the user expression. This will hide our wrapper code
// from the user when we render diagnostics with Clang.
m_start_marker = "#line 1 \"" + filename.str() + "\"\n";
m_end_marker = "\n;\n#line 1 \"<lldb wrapper suffix>\"\n";
}
namespace {
/// Allows checking if a token is contained in a given expression.
class TokenVerifier {
/// The tokens we found in the expression.
llvm::StringSet<> m_tokens;
public:
TokenVerifier(std::string body);
/// Returns true iff the given expression body contained a token with the
/// given content.
bool hasToken(llvm::StringRef token) const {
return m_tokens.find(token) != m_tokens.end();
}
};
} // namespace
TokenVerifier::TokenVerifier(std::string body) {
using namespace clang;
// We only care about tokens and not their original source locations. If we
// move the whole expression to only be in one line we can simplify the
// following code that extracts the token contents.
std::replace(body.begin(), body.end(), '\n', ' ');
std::replace(body.begin(), body.end(), '\r', ' ');
FileSystemOptions file_opts;
FileManager file_mgr(file_opts,
FileSystem::Instance().GetVirtualFileSystem());
// Let's build the actual source code Clang needs and setup some utility
// objects.
llvm::IntrusiveRefCntPtr<DiagnosticIDs> diag_ids(new DiagnosticIDs());
llvm::IntrusiveRefCntPtr<DiagnosticOptions> diags_opts(
new DiagnosticOptions());
DiagnosticsEngine diags(diag_ids, diags_opts);
clang::SourceManager SM(diags, file_mgr);
auto buf = llvm::MemoryBuffer::getMemBuffer(body);
FileID FID = SM.createFileID(clang::SourceManager::Unowned, buf.get());
// Let's just enable the latest ObjC and C++ which should get most tokens
// right.
LangOptions Opts;
Opts.ObjC = true;
Opts.DollarIdents = true;
Opts.CPlusPlus17 = true;
Opts.LineComment = true;
Lexer lex(FID, buf.get(), SM, Opts);
Token token;
bool exit = false;
while (!exit) {
// Returns true if this is the last token we get from the lexer.
exit = lex.LexFromRawLexer(token);
// Extract the column number which we need to extract the token content.
// Our expression is just one line, so we don't need to handle any line
// numbers here.
bool invalid = false;
unsigned start = SM.getSpellingColumnNumber(token.getLocation(), &invalid);
if (invalid)
continue;
// Column numbers start at 1, but indexes in our string start at 0.
--start;
// Annotations don't have a length, so let's skip them.
if (token.isAnnotation())
continue;
// Extract the token string from our source code and store it.
std::string token_str = body.substr(start, token.getLength());
if (token_str.empty())
continue;
m_tokens.insert(token_str);
}
}
void ClangExpressionSourceCode::AddLocalVariableDecls(
const lldb::VariableListSP &var_list_sp, StreamString &stream,
const std::string &expr) const {
TokenVerifier tokens(expr);
for (size_t i = 0; i < var_list_sp->GetSize(); i++) {
lldb::VariableSP var_sp = var_list_sp->GetVariableAtIndex(i);
ConstString var_name = var_sp->GetName();
// We can check for .block_descriptor w/o checking for langauge since this
// is not a valid identifier in either C or C++.
if (!var_name || var_name == ".block_descriptor")
continue;
if (!expr.empty() && !tokens.hasToken(var_name.GetStringRef()))
continue;
const bool is_objc = m_wrap_kind == WrapKind::ObjCInstanceMethod ||
m_wrap_kind == WrapKind::ObjCStaticMethod;
if ((var_name == "self" || var_name == "_cmd") && is_objc)
continue;
if (var_name == "this" && m_wrap_kind == WrapKind::CppMemberFunction)
continue;
stream.Printf("using $__lldb_local_vars::%s;\n", var_name.AsCString());
}
}
bool ClangExpressionSourceCode::GetText(
std::string &text, ExecutionContext &exe_ctx, bool add_locals,
bool force_add_all_locals, llvm::ArrayRef<std::string> modules) const {
const char *target_specific_defines = "typedef signed char BOOL;\n";
std::string module_macros;
Target *target = exe_ctx.GetTargetPtr();
if (target) {
if (target->GetArchitecture().GetMachine() == llvm::Triple::aarch64 ||
target->GetArchitecture().GetMachine() == llvm::Triple::aarch64_32) {
target_specific_defines = "typedef bool BOOL;\n";
}
if (target->GetArchitecture().GetMachine() == llvm::Triple::x86_64) {
if (lldb::PlatformSP platform_sp = target->GetPlatform()) {
static ConstString g_platform_ios_simulator("ios-simulator");
if (platform_sp->GetPluginName() == g_platform_ios_simulator) {
target_specific_defines = "typedef bool BOOL;\n";
}
}
}
ClangModulesDeclVendor *decl_vendor = target->GetClangModulesDeclVendor();
auto *persistent_vars = llvm::cast<ClangPersistentVariables>(
target->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC));
if (decl_vendor && persistent_vars) {
const ClangModulesDeclVendor::ModuleVector &hand_imported_modules =
persistent_vars->GetHandLoadedClangModules();
ClangModulesDeclVendor::ModuleVector modules_for_macros;
for (ClangModulesDeclVendor::ModuleID module : hand_imported_modules) {
modules_for_macros.push_back(module);
}
if (target->GetEnableAutoImportClangModules()) {
if (StackFrame *frame = exe_ctx.GetFramePtr()) {
if (Block *block = frame->GetFrameBlock()) {
SymbolContext sc;
block->CalculateSymbolContext(&sc);
if (sc.comp_unit) {
StreamString error_stream;
decl_vendor->AddModulesForCompileUnit(
*sc.comp_unit, modules_for_macros, error_stream);
}
}
}
}
decl_vendor->ForEachMacro(
modules_for_macros,
[&module_macros](const std::string &expansion) -> bool {
module_macros.append(expansion);
module_macros.append("\n");
return false;
});
}
}
StreamString debug_macros_stream;
StreamString lldb_local_var_decls;
if (StackFrame *frame = exe_ctx.GetFramePtr()) {
const SymbolContext &sc = frame->GetSymbolContext(
lldb::eSymbolContextCompUnit | lldb::eSymbolContextLineEntry);
if (sc.comp_unit && sc.line_entry.IsValid()) {
DebugMacros *dm = sc.comp_unit->GetDebugMacros();
if (dm) {
AddMacroState state(sc.line_entry.file, sc.line_entry.line);
AddMacros(dm, sc.comp_unit, state, debug_macros_stream);
}
}
if (add_locals)
if (target->GetInjectLocalVariables(&exe_ctx)) {
lldb::VariableListSP var_list_sp =
frame->GetInScopeVariableList(false, true);
AddLocalVariableDecls(var_list_sp, lldb_local_var_decls,
force_add_all_locals ? "" : m_body);
}
}
if (m_wrap) {
// Generate a list of @import statements that will import the specified
// module into our expression.
std::string module_imports;
for (const std::string &module : modules) {
module_imports.append("@import ");
module_imports.append(module);
module_imports.append(";\n");
}
StreamString wrap_stream;
wrap_stream.Printf("%s\n%s\n%s\n%s\n%s\n", module_macros.c_str(),
debug_macros_stream.GetData(), g_expression_prefix,
target_specific_defines, m_prefix.c_str());
// First construct a tagged form of the user expression so we can find it
// later:
std::string tagged_body;
tagged_body.append(m_start_marker);
tagged_body.append(m_body);
tagged_body.append(m_end_marker);
switch (m_wrap_kind) {
case WrapKind::Function:
wrap_stream.Printf("%s"
"void \n"
"%s(void *$__lldb_arg) \n"
"{ \n"
" %s; \n"
"%s"
"} \n",
module_imports.c_str(), m_name.c_str(),
lldb_local_var_decls.GetData(), tagged_body.c_str());
break;
case WrapKind::CppMemberFunction:
wrap_stream.Printf("%s"
"void \n"
"$__lldb_class::%s(void *$__lldb_arg) \n"
"{ \n"
" %s; \n"
"%s"
"} \n",
module_imports.c_str(), m_name.c_str(),
lldb_local_var_decls.GetData(), tagged_body.c_str());
break;
case WrapKind::ObjCInstanceMethod:
wrap_stream.Printf(
"%s"
"@interface $__lldb_objc_class ($__lldb_category) \n"
"-(void)%s:(void *)$__lldb_arg; \n"
"@end \n"
"@implementation $__lldb_objc_class ($__lldb_category) \n"
"-(void)%s:(void *)$__lldb_arg \n"
"{ \n"
" %s; \n"
"%s"
"} \n"
"@end \n",
module_imports.c_str(), m_name.c_str(), m_name.c_str(),
lldb_local_var_decls.GetData(), tagged_body.c_str());
break;
case WrapKind::ObjCStaticMethod:
wrap_stream.Printf(
"%s"
"@interface $__lldb_objc_class ($__lldb_category) \n"
"+(void)%s:(void *)$__lldb_arg; \n"
"@end \n"
"@implementation $__lldb_objc_class ($__lldb_category) \n"
"+(void)%s:(void *)$__lldb_arg \n"
"{ \n"
" %s; \n"
"%s"
"} \n"
"@end \n",
module_imports.c_str(), m_name.c_str(), m_name.c_str(),
lldb_local_var_decls.GetData(), tagged_body.c_str());
break;
}
text = std::string(wrap_stream.GetString());
} else {
text.append(m_body);
}
return true;
}
bool ClangExpressionSourceCode::GetOriginalBodyBounds(
std::string transformed_text, size_t &start_loc, size_t &end_loc) {
start_loc = transformed_text.find(m_start_marker);
if (start_loc == std::string::npos)
return false;
start_loc += m_start_marker.size();
end_loc = transformed_text.find(m_end_marker);
return end_loc != std::string::npos;
}