1 //===-- FunctionCaller.cpp ---------------------------------------*- C++-*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 
10 #include "lldb/Expression/FunctionCaller.h"
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ValueObject.h"
13 #include "lldb/Core/ValueObjectList.h"
14 #include "lldb/Expression/DiagnosticManager.h"
15 #include "lldb/Expression/IRExecutionUnit.h"
16 #include "lldb/Interpreter/CommandReturnObject.h"
17 #include "lldb/Symbol/Function.h"
18 #include "lldb/Symbol/Type.h"
19 #include "lldb/Target/ExecutionContext.h"
20 #include "lldb/Target/Process.h"
21 #include "lldb/Target/RegisterContext.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Target/Thread.h"
24 #include "lldb/Target/ThreadPlan.h"
25 #include "lldb/Target/ThreadPlanCallFunction.h"
26 #include "lldb/Utility/DataExtractor.h"
27 #include "lldb/Utility/Log.h"
28 #include "lldb/Utility/State.h"
29 
30 using namespace lldb_private;
31 
32 //----------------------------------------------------------------------
33 // FunctionCaller constructor
34 //----------------------------------------------------------------------
35 FunctionCaller::FunctionCaller(ExecutionContextScope &exe_scope,
36                                const CompilerType &return_type,
37                                const Address &functionAddress,
38                                const ValueList &arg_value_list,
39                                const char *name)
40     : Expression(exe_scope, eKindFunctionCaller),
41       m_execution_unit_sp(), m_parser(),
42       m_jit_module_wp(), m_name(name ? name : "<unknown>"),
43       m_function_ptr(NULL), m_function_addr(functionAddress),
44       m_function_return_type(return_type),
45       m_wrapper_function_name("__lldb_caller_function"),
46       m_wrapper_struct_name("__lldb_caller_struct"), m_wrapper_args_addrs(),
47       m_struct_valid(false), m_arg_values(arg_value_list), m_compiled(false),
48       m_JITted(false) {
49   m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
50   // Can't make a FunctionCaller without a process.
51   assert(m_jit_process_wp.lock());
52 }
53 
54 //----------------------------------------------------------------------
55 // Destructor
56 //----------------------------------------------------------------------
57 FunctionCaller::~FunctionCaller() {
58   lldb::ProcessSP process_sp(m_jit_process_wp.lock());
59   if (process_sp) {
60     lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
61     if (jit_module_sp)
62       process_sp->GetTarget().GetImages().Remove(jit_module_sp);
63   }
64 }
65 
66 bool FunctionCaller::WriteFunctionWrapper(
67     ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
68   Process *process = exe_ctx.GetProcessPtr();
69 
70   if (!process)
71     return false;
72 
73   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
74 
75   if (process != jit_process_sp.get())
76     return false;
77 
78   if (!m_compiled)
79     return false;
80 
81   if (m_JITted)
82     return true;
83 
84   bool can_interpret = false; // should stay that way
85 
86   Status jit_error(m_parser->PrepareForExecution(
87       m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
88       can_interpret, eExecutionPolicyAlways));
89 
90   if (!jit_error.Success()) {
91     diagnostic_manager.Printf(eDiagnosticSeverityError,
92                               "Error in PrepareForExecution: %s.",
93                               jit_error.AsCString());
94     return false;
95   }
96 
97   if (m_parser->GetGenerateDebugInfo()) {
98     lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
99 
100     if (jit_module_sp) {
101       ConstString const_func_name(FunctionName());
102       FileSpec jit_file;
103       jit_file.GetFilename() = const_func_name;
104       jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
105       m_jit_module_wp = jit_module_sp;
106       process->GetTarget().GetImages().Append(jit_module_sp,
107                                               true /* notify */);
108     }
109   }
110   if (process && m_jit_start_addr)
111     m_jit_process_wp = process->shared_from_this();
112 
113   m_JITted = true;
114 
115   return true;
116 }
117 
118 bool FunctionCaller::WriteFunctionArguments(
119     ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
120     DiagnosticManager &diagnostic_manager) {
121   return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
122                                 diagnostic_manager);
123 }
124 
125 // FIXME: Assure that the ValueList we were passed in is consistent with the one
126 // that defined this function.
127 
128 bool FunctionCaller::WriteFunctionArguments(
129     ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
130     ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
131   // All the information to reconstruct the struct is provided by the
132   // StructExtractor.
133   if (!m_struct_valid) {
134     diagnostic_manager.PutString(eDiagnosticSeverityError,
135                                  "Argument information was not correctly "
136                                  "parsed, so the function cannot be called.");
137     return false;
138   }
139 
140   Status error;
141   lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
142 
143   Process *process = exe_ctx.GetProcessPtr();
144 
145   if (process == NULL)
146     return return_value;
147 
148   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
149 
150   if (process != jit_process_sp.get())
151     return false;
152 
153   if (args_addr_ref == LLDB_INVALID_ADDRESS) {
154     args_addr_ref = process->AllocateMemory(
155         m_struct_size, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
156         error);
157     if (args_addr_ref == LLDB_INVALID_ADDRESS)
158       return false;
159     m_wrapper_args_addrs.push_back(args_addr_ref);
160   } else {
161     // Make sure this is an address that we've already handed out.
162     if (find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
163              args_addr_ref) == m_wrapper_args_addrs.end()) {
164       return false;
165     }
166   }
167 
168   // TODO: verify fun_addr needs to be a callable address
169   Scalar fun_addr(
170       m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
171   uint64_t first_offset = m_member_offsets[0];
172   process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
173                                process->GetAddressByteSize(), error);
174 
175   // FIXME: We will need to extend this for Variadic functions.
176 
177   Status value_error;
178 
179   size_t num_args = arg_values.GetSize();
180   if (num_args != m_arg_values.GetSize()) {
181     diagnostic_manager.Printf(
182         eDiagnosticSeverityError,
183         "Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
184         (uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
185     return false;
186   }
187 
188   for (size_t i = 0; i < num_args; i++) {
189     // FIXME: We should sanity check sizes.
190 
191     uint64_t offset = m_member_offsets[i + 1]; // Clang sizes are in bytes.
192     Value *arg_value = arg_values.GetValueAtIndex(i);
193 
194     // FIXME: For now just do scalars:
195 
196     // Special case: if it's a pointer, don't do anything (the ABI supports
197     // passing cstrings)
198 
199     if (arg_value->GetValueType() == Value::eValueTypeHostAddress &&
200         arg_value->GetContextType() == Value::eContextTypeInvalid &&
201         arg_value->GetCompilerType().IsPointerType())
202       continue;
203 
204     const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
205 
206     if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
207                                       arg_scalar.GetByteSize(), error))
208       return false;
209   }
210 
211   return true;
212 }
213 
214 bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
215                                     lldb::addr_t &args_addr_ref,
216                                     DiagnosticManager &diagnostic_manager) {
217   if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
218     return false;
219   if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
220     return false;
221   if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
222     return false;
223 
224   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
225   if (log)
226     log->Printf("Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
227                 m_jit_start_addr, args_addr_ref);
228 
229   return true;
230 }
231 
232 lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
233     ExecutionContext &exe_ctx, lldb::addr_t args_addr,
234     const EvaluateExpressionOptions &options,
235     DiagnosticManager &diagnostic_manager) {
236   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
237                                                   LIBLLDB_LOG_STEP));
238 
239   if (log)
240     log->Printf("-- [FunctionCaller::GetThreadPlanToCallFunction] Creating "
241                 "thread plan to call function \"%s\" --",
242                 m_name.c_str());
243 
244   // FIXME: Use the errors Stream for better error reporting.
245   Thread *thread = exe_ctx.GetThreadPtr();
246   if (thread == NULL) {
247     diagnostic_manager.PutString(
248         eDiagnosticSeverityError,
249         "Can't call a function without a valid thread.");
250     return NULL;
251   }
252 
253   // Okay, now run the function:
254 
255   Address wrapper_address(m_jit_start_addr);
256 
257   lldb::addr_t args = {args_addr};
258 
259   lldb::ThreadPlanSP new_plan_sp(new ThreadPlanCallFunction(
260       *thread, wrapper_address, CompilerType(), args, options));
261   new_plan_sp->SetIsMasterPlan(true);
262   new_plan_sp->SetOkayToDiscard(false);
263   return new_plan_sp;
264 }
265 
266 bool FunctionCaller::FetchFunctionResults(ExecutionContext &exe_ctx,
267                                           lldb::addr_t args_addr,
268                                           Value &ret_value) {
269   // Read the return value - it is the last field in the struct:
270   // FIXME: How does clang tell us there's no return value?  We need to handle
271   // that case.
272   // FIXME: Create our ThreadPlanCallFunction with the return CompilerType, and
273   // then use GetReturnValueObject
274   // to fetch the value.  That way we can fetch any values we need.
275 
276   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
277                                                   LIBLLDB_LOG_STEP));
278 
279   if (log)
280     log->Printf("-- [FunctionCaller::FetchFunctionResults] Fetching function "
281                 "results for \"%s\"--",
282                 m_name.c_str());
283 
284   Process *process = exe_ctx.GetProcessPtr();
285 
286   if (process == NULL)
287     return false;
288 
289   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
290 
291   if (process != jit_process_sp.get())
292     return false;
293 
294   Status error;
295   ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
296       args_addr + m_return_offset, m_return_size, 0, error);
297 
298   if (error.Fail())
299     return false;
300 
301   ret_value.SetCompilerType(m_function_return_type);
302   ret_value.SetValueType(Value::eValueTypeScalar);
303   return true;
304 }
305 
306 void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
307                                                lldb::addr_t args_addr) {
308   std::list<lldb::addr_t>::iterator pos;
309   pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
310                   args_addr);
311   if (pos != m_wrapper_args_addrs.end())
312     m_wrapper_args_addrs.erase(pos);
313 
314   exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
315 }
316 
317 lldb::ExpressionResults FunctionCaller::ExecuteFunction(
318     ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
319     const EvaluateExpressionOptions &options,
320     DiagnosticManager &diagnostic_manager, Value &results) {
321   lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
322 
323   // FunctionCaller::ExecuteFunction execution is always just to get the
324   // result. Do make sure we ignore breakpoints, unwind on error, and don't try
325   // to debug it.
326   EvaluateExpressionOptions real_options = options;
327   real_options.SetDebug(false);
328   real_options.SetUnwindOnError(true);
329   real_options.SetIgnoreBreakpoints(true);
330 
331   lldb::addr_t args_addr;
332 
333   if (args_addr_ptr != NULL)
334     args_addr = *args_addr_ptr;
335   else
336     args_addr = LLDB_INVALID_ADDRESS;
337 
338   if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
339     return lldb::eExpressionSetupError;
340 
341   if (args_addr == LLDB_INVALID_ADDRESS) {
342     if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
343       return lldb::eExpressionSetupError;
344   }
345 
346   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
347                                                   LIBLLDB_LOG_STEP));
348 
349   if (log)
350     log->Printf(
351         "== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
352         m_name.c_str());
353 
354   lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
355       exe_ctx, args_addr, real_options, diagnostic_manager);
356   if (!call_plan_sp)
357     return lldb::eExpressionSetupError;
358 
359   // We need to make sure we record the fact that we are running an expression
360   // here otherwise this fact will fail to be recorded when fetching an
361   // Objective-C object description
362   if (exe_ctx.GetProcessPtr())
363     exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
364 
365   return_value = exe_ctx.GetProcessRef().RunThreadPlan(
366       exe_ctx, call_plan_sp, real_options, diagnostic_manager);
367 
368   if (log) {
369     if (return_value != lldb::eExpressionCompleted) {
370       log->Printf("== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
371                   "completed abnormally ==",
372                   m_name.c_str());
373     } else {
374       log->Printf("== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
375                   "completed normally ==",
376                   m_name.c_str());
377     }
378   }
379 
380   if (exe_ctx.GetProcessPtr())
381     exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
382 
383   if (args_addr_ptr != NULL)
384     *args_addr_ptr = args_addr;
385 
386   if (return_value != lldb::eExpressionCompleted)
387     return return_value;
388 
389   FetchFunctionResults(exe_ctx, args_addr, results);
390 
391   if (args_addr_ptr == NULL)
392     DeallocateFunctionResults(exe_ctx, args_addr);
393 
394   return lldb::eExpressionCompleted;
395 }
396