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