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clang-p2996/lldb/source/Commands/CommandObjectDisassemble.h
Pavel Labath 8b845ac5ed Recommit "[lldb] Don't dissasemble large functions by default"
This recommits f665e80c02 which was reverted in 1cbd1b8f69 for breaking
TestFoundationDisassembly.py. The fix is to use --force in the test to avoid
bailing out on large functions.

I have also doubled the large function limit to 8000 bytes (~~ 2000 insns), as
the foundation library contains a lot of large-ish functions. The intent of this
feature is to prevent accidental disassembling of enormous (multi-megabyte)
"functions", not to get in people's way.

The original commit message follows:

If we have a binary without symbol information (and without
LC_FUNCTION_STARTS, if on a mac), then we have to resort to using
heuristics to determine the function boundaries. However, these don't
always work, and so we can easily end up thinking we have functions
which are several megabytes in size. Attempting to (accidentally)
disassemble these can take a very long time spam the terminal with
thousands of lines of disassembly.

This patch works around that problem by adding a sanity check to the
disassemble command. If we are about to disassemble a function which is
larger than a certain threshold, we will refuse to disassemble such a
function unless the user explicitly specifies the number of instructions
to disassemble, uses start/stop addresses for disassembly, or passes the
(new) --force argument.

The threshold is currently fairly aggressive (4000 bytes ~~ 1000
instructions). If needed, we can increase it, or even make it
configurable.

Differential Revision: https://reviews.llvm.org/D79789
2020-05-15 11:57:48 +02:00

96 lines
3.0 KiB
C++

//===-- CommandObjectDisassemble.h ------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_SOURCE_COMMANDS_COMMANDOBJECTDISASSEMBLE_H
#define LLDB_SOURCE_COMMANDS_COMMANDOBJECTDISASSEMBLE_H
#include "lldb/Interpreter/CommandObject.h"
#include "lldb/Interpreter/Options.h"
#include "lldb/Utility/ArchSpec.h"
namespace lldb_private {
// CommandObjectDisassemble
class CommandObjectDisassemble : public CommandObjectParsed {
public:
class CommandOptions : public Options {
public:
CommandOptions();
~CommandOptions() override;
Status SetOptionValue(uint32_t option_idx, llvm::StringRef option_arg,
ExecutionContext *execution_context) override;
void OptionParsingStarting(ExecutionContext *execution_context) override;
llvm::ArrayRef<OptionDefinition> GetDefinitions() override;
const char *GetPluginName() {
return (plugin_name.empty() ? nullptr : plugin_name.c_str());
}
const char *GetFlavorString() {
if (flavor_string.empty() || flavor_string == "default")
return nullptr;
return flavor_string.c_str();
}
Status OptionParsingFinished(ExecutionContext *execution_context) override;
bool show_mixed; // Show mixed source/assembly
bool show_bytes;
uint32_t num_lines_context;
uint32_t num_instructions;
bool raw;
std::string func_name;
bool current_function;
lldb::addr_t start_addr;
lldb::addr_t end_addr;
bool at_pc;
bool frame_line;
std::string plugin_name;
std::string flavor_string;
ArchSpec arch;
bool some_location_specified; // If no location was specified, we'll select
// "at_pc". This should be set
// in SetOptionValue if anything the selects a location is set.
lldb::addr_t symbol_containing_addr;
bool force = false;
};
CommandObjectDisassemble(CommandInterpreter &interpreter);
~CommandObjectDisassemble() override;
Options *GetOptions() override { return &m_options; }
protected:
bool DoExecute(Args &command, CommandReturnObject &result) override;
llvm::Expected<std::vector<AddressRange>>
GetRangesForSelectedMode(CommandReturnObject &result);
llvm::Expected<std::vector<AddressRange>> GetContainingAddressRanges();
llvm::Expected<std::vector<AddressRange>> GetCurrentFunctionRanges();
llvm::Expected<std::vector<AddressRange>> GetCurrentLineRanges();
llvm::Expected<std::vector<AddressRange>>
GetNameRanges(CommandReturnObject &result);
llvm::Expected<std::vector<AddressRange>> GetPCRanges();
llvm::Expected<std::vector<AddressRange>> GetStartEndAddressRanges();
llvm::Error CheckRangeSize(const AddressRange &range, llvm::StringRef what);
CommandOptions m_options;
};
} // namespace lldb_private
#endif // LLDB_SOURCE_COMMANDS_COMMANDOBJECTDISASSEMBLE_H