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