mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alessandro Di Federico
6ae0610e2d
This commit switches all scripts to Python 3, except for `revng-merge-dynamic` which requires Python 2 due to a limitation of pyelftools.
69 lines
2.6 KiB
Python
69 lines
2.6 KiB
Python
#!/usr/bin/env python3
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import sys
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from llvmcpy import llvm
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def main():
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context = llvm.get_global_context()
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# Load and parse the input file
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buffer = llvm.create_memory_buffer_with_contents_of_file(sys.argv[1])
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module = context.parse_ir(buffer)
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# Identify the CSV (global variable) for the register containing the syscall
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# number (r7 for ARM)
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r7 = module.get_named_global("r7")
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# Prepare requirements to build our call to dprintf
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# 1) Identify the dprintf function (prototype)
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dprintf = module.get_named_function("dprintf")
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# 2) Create an integer constant for stderr
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two = context.int32_type().const_int(2, True)
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# 3) Create the message to print
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message_str = context.const_string("%d\n", 4, True)
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message = module.add_global(message_str.type_of(), "message")
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message.set_initializer(message_str)
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message_ptr = message.const_bit_cast(context.int8_type().pointer(0))
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# Identify the function generated by revng (root)
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root_function = module.get_named_function("root")
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# Loop over all the generated instructions and add instrumentation code
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builder = context.create_builder()
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for basic_block in root_function.iter_basic_blocks():
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for instruction in basic_block.iter_instructions():
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# Check if the current instruction is a call
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if instruction.instruction_opcode == llvm.Call:
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# The callee is the last operand
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last_operand_index = instruction.get_num_operands() - 1
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callee = instruction.get_operand(last_operand_index)
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# If there's a bitcast, skip it
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if not callee.name:
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assert(callee.get_num_operands() == 1)
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callee = callee.get_operand(0)
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# Check if it's performing a syscall
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if callee.name.startswith("helper_exception_with_syndrome_"):
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# Set the builder's insert point before the call instruction
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builder.position_builder_before(instruction)
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# Load the value of r7 (which contains the syscall number)
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load_r7 = builder.build_load(r7, "")
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# Create the list of arguments for dprintf
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arguments = [two, message_ptr, load_r7]
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# Create the function call to dprintf:
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# dprintf(2, "%d\n", r7)
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builder.build_call(dprintf, arguments, "")
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# Produce the instrumented LLVM IR to file
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module.print_module_to_file(sys.argv[2])
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if __name__ == "__main__":
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main()
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