1 //===-- Function.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 #include "lldb/Symbol/Function.h"
10 #include "lldb/Core/Disassembler.h"
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ModuleList.h"
13 #include "lldb/Core/Section.h"
14 #include "lldb/Host/Host.h"
15 #include "lldb/Symbol/CompileUnit.h"
16 #include "lldb/Symbol/CompilerType.h"
17 #include "lldb/Symbol/LineTable.h"
18 #include "lldb/Symbol/SymbolFile.h"
19 #include "lldb/Target/Language.h"
20 #include "lldb/Utility/Log.h"
21 #include "llvm/Support/Casting.h"
22 
23 using namespace lldb;
24 using namespace lldb_private;
25 
26 // Basic function information is contained in the FunctionInfo class. It is
27 // designed to contain the name, linkage name, and declaration location.
28 FunctionInfo::FunctionInfo(const char *name, const Declaration *decl_ptr)
29     : m_name(name), m_declaration(decl_ptr) {}
30 
31 FunctionInfo::FunctionInfo(ConstString name, const Declaration *decl_ptr)
32     : m_name(name), m_declaration(decl_ptr) {}
33 
34 FunctionInfo::~FunctionInfo() {}
35 
36 void FunctionInfo::Dump(Stream *s, bool show_fullpaths) const {
37   if (m_name)
38     *s << ", name = \"" << m_name << "\"";
39   m_declaration.Dump(s, show_fullpaths);
40 }
41 
42 int FunctionInfo::Compare(const FunctionInfo &a, const FunctionInfo &b) {
43   int result = ConstString::Compare(a.GetName(), b.GetName());
44   if (result)
45     return result;
46 
47   return Declaration::Compare(a.m_declaration, b.m_declaration);
48 }
49 
50 Declaration &FunctionInfo::GetDeclaration() { return m_declaration; }
51 
52 const Declaration &FunctionInfo::GetDeclaration() const {
53   return m_declaration;
54 }
55 
56 ConstString FunctionInfo::GetName() const { return m_name; }
57 
58 size_t FunctionInfo::MemorySize() const {
59   return m_name.MemorySize() + m_declaration.MemorySize();
60 }
61 
62 InlineFunctionInfo::InlineFunctionInfo(const char *name, const char *mangled,
63                                        const Declaration *decl_ptr,
64                                        const Declaration *call_decl_ptr)
65     : FunctionInfo(name, decl_ptr), m_mangled(ConstString(mangled), true),
66       m_call_decl(call_decl_ptr) {}
67 
68 InlineFunctionInfo::InlineFunctionInfo(ConstString name,
69                                        const Mangled &mangled,
70                                        const Declaration *decl_ptr,
71                                        const Declaration *call_decl_ptr)
72     : FunctionInfo(name, decl_ptr), m_mangled(mangled),
73       m_call_decl(call_decl_ptr) {}
74 
75 InlineFunctionInfo::~InlineFunctionInfo() {}
76 
77 int InlineFunctionInfo::Compare(const InlineFunctionInfo &a,
78                                 const InlineFunctionInfo &b) {
79 
80   int result = FunctionInfo::Compare(a, b);
81   if (result)
82     return result;
83   // only compare the mangled names if both have them
84   return Mangled::Compare(a.m_mangled, a.m_mangled);
85 }
86 
87 void InlineFunctionInfo::Dump(Stream *s, bool show_fullpaths) const {
88   FunctionInfo::Dump(s, show_fullpaths);
89   if (m_mangled)
90     m_mangled.Dump(s);
91 }
92 
93 void InlineFunctionInfo::DumpStopContext(Stream *s,
94                                          LanguageType language) const {
95   //    s->Indent("[inlined] ");
96   s->Indent();
97   if (m_mangled)
98     s->PutCString(m_mangled.GetName(language).AsCString());
99   else
100     s->PutCString(m_name.AsCString());
101 }
102 
103 ConstString InlineFunctionInfo::GetName(LanguageType language) const {
104   if (m_mangled)
105     return m_mangled.GetName(language);
106   return m_name;
107 }
108 
109 ConstString InlineFunctionInfo::GetDisplayName(LanguageType language) const {
110   if (m_mangled)
111     return m_mangled.GetDisplayDemangledName(language);
112   return m_name;
113 }
114 
115 Declaration &InlineFunctionInfo::GetCallSite() { return m_call_decl; }
116 
117 const Declaration &InlineFunctionInfo::GetCallSite() const {
118   return m_call_decl;
119 }
120 
121 Mangled &InlineFunctionInfo::GetMangled() { return m_mangled; }
122 
123 const Mangled &InlineFunctionInfo::GetMangled() const { return m_mangled; }
124 
125 size_t InlineFunctionInfo::MemorySize() const {
126   return FunctionInfo::MemorySize() + m_mangled.MemorySize();
127 }
128 
129 //
130 CallEdge::CallEdge(const char *symbol_name, lldb::addr_t return_pc,
131                    CallSiteParameterArray parameters)
132     : return_pc(return_pc), parameters(std::move(parameters)), resolved(false) {
133   lazy_callee.symbol_name = symbol_name;
134 }
135 
136 llvm::ArrayRef<CallSiteParameter> CallEdge::GetCallSiteParameters() const {
137   return parameters;
138 }
139 
140 void CallEdge::ParseSymbolFileAndResolve(ModuleList &images) {
141   if (resolved)
142     return;
143 
144   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
145   LLDB_LOG(log, "CallEdge: Lazily parsing the call graph for {0}",
146            lazy_callee.symbol_name);
147 
148   auto resolve_lazy_callee = [&]() -> Function * {
149     ConstString callee_name{lazy_callee.symbol_name};
150     SymbolContextList sc_list;
151     size_t num_matches =
152         images.FindFunctionSymbols(callee_name, eFunctionNameTypeAuto, sc_list);
153     if (num_matches == 0 || !sc_list[0].symbol) {
154       LLDB_LOG(log, "CallEdge: Found no symbols for {0}, cannot resolve it",
155                callee_name);
156       return nullptr;
157     }
158     Address callee_addr = sc_list[0].symbol->GetAddress();
159     if (!callee_addr.IsValid()) {
160       LLDB_LOG(log, "CallEdge: Invalid symbol address");
161       return nullptr;
162     }
163     Function *f = callee_addr.CalculateSymbolContextFunction();
164     if (!f) {
165       LLDB_LOG(log, "CallEdge: Could not find complete function");
166       return nullptr;
167     }
168     return f;
169   };
170   lazy_callee.def = resolve_lazy_callee();
171   resolved = true;
172 }
173 
174 Function *CallEdge::GetCallee(ModuleList &images) {
175   ParseSymbolFileAndResolve(images);
176   return lazy_callee.def;
177 }
178 
179 lldb::addr_t CallEdge::GetReturnPCAddress(Function &caller,
180                                           Target &target) const {
181   const Address &base = caller.GetAddressRange().GetBaseAddress();
182   return base.GetLoadAddress(&target) + return_pc;
183 }
184 
185 //
186 Function::Function(CompileUnit *comp_unit, lldb::user_id_t func_uid,
187                    lldb::user_id_t type_uid, const Mangled &mangled, Type *type,
188                    const AddressRange &range)
189     : UserID(func_uid), m_comp_unit(comp_unit), m_type_uid(type_uid),
190       m_type(type), m_mangled(mangled), m_block(func_uid), m_range(range),
191       m_frame_base(), m_flags(), m_prologue_byte_size(0) {
192   m_block.SetParentScope(this);
193   assert(comp_unit != nullptr);
194 }
195 
196 Function::~Function() {}
197 
198 void Function::GetStartLineSourceInfo(FileSpec &source_file,
199                                       uint32_t &line_no) {
200   line_no = 0;
201   source_file.Clear();
202 
203   if (m_comp_unit == nullptr)
204     return;
205 
206   // Initialize m_type if it hasn't been initialized already
207   GetType();
208 
209   if (m_type != nullptr && m_type->GetDeclaration().GetLine() != 0) {
210     source_file = m_type->GetDeclaration().GetFile();
211     line_no = m_type->GetDeclaration().GetLine();
212   } else {
213     LineTable *line_table = m_comp_unit->GetLineTable();
214     if (line_table == nullptr)
215       return;
216 
217     LineEntry line_entry;
218     if (line_table->FindLineEntryByAddress(GetAddressRange().GetBaseAddress(),
219                                            line_entry, nullptr)) {
220       line_no = line_entry.line;
221       source_file = line_entry.file;
222     }
223   }
224 }
225 
226 void Function::GetEndLineSourceInfo(FileSpec &source_file, uint32_t &line_no) {
227   line_no = 0;
228   source_file.Clear();
229 
230   // The -1 is kind of cheesy, but I want to get the last line entry for the
231   // given function, not the first entry of the next.
232   Address scratch_addr(GetAddressRange().GetBaseAddress());
233   scratch_addr.SetOffset(scratch_addr.GetOffset() +
234                          GetAddressRange().GetByteSize() - 1);
235 
236   LineTable *line_table = m_comp_unit->GetLineTable();
237   if (line_table == nullptr)
238     return;
239 
240   LineEntry line_entry;
241   if (line_table->FindLineEntryByAddress(scratch_addr, line_entry, nullptr)) {
242     line_no = line_entry.line;
243     source_file = line_entry.file;
244   }
245 }
246 
247 llvm::MutableArrayRef<CallEdge> Function::GetCallEdges() {
248   if (m_call_edges_resolved)
249     return m_call_edges;
250 
251   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
252   LLDB_LOG(log, "GetCallEdges: Attempting to parse call site info for {0}",
253            GetDisplayName());
254 
255   m_call_edges_resolved = true;
256 
257   // Find the SymbolFile which provided this function's definition.
258   Block &block = GetBlock(/*can_create*/true);
259   SymbolFile *sym_file = block.GetSymbolFile();
260   if (!sym_file)
261     return llvm::None;
262 
263   // Lazily read call site information from the SymbolFile.
264   m_call_edges = sym_file->ParseCallEdgesInFunction(GetID());
265 
266   // Sort the call edges to speed up return_pc lookups.
267   llvm::sort(m_call_edges.begin(), m_call_edges.end(),
268              [](const CallEdge &LHS, const CallEdge &RHS) {
269                return LHS.GetUnresolvedReturnPCAddress() <
270                       RHS.GetUnresolvedReturnPCAddress();
271              });
272 
273   return m_call_edges;
274 }
275 
276 llvm::MutableArrayRef<CallEdge> Function::GetTailCallingEdges() {
277   // Call edges are sorted by return PC, and tail calling edges have invalid
278   // return PCs. Find them at the end of the list.
279   return GetCallEdges().drop_until([](const CallEdge &edge) {
280     return edge.GetUnresolvedReturnPCAddress() == LLDB_INVALID_ADDRESS;
281   });
282 }
283 
284 CallEdge *Function::GetCallEdgeForReturnAddress(addr_t return_pc,
285                                                 Target &target) {
286   auto edges = GetCallEdges();
287   auto edge_it =
288       std::lower_bound(edges.begin(), edges.end(), return_pc,
289                        [&](const CallEdge &edge, addr_t pc) {
290                          return edge.GetReturnPCAddress(*this, target) < pc;
291                        });
292   if (edge_it == edges.end() ||
293       edge_it->GetReturnPCAddress(*this, target) != return_pc)
294     return nullptr;
295   return &const_cast<CallEdge &>(*edge_it);
296 }
297 
298 Block &Function::GetBlock(bool can_create) {
299   if (!m_block.BlockInfoHasBeenParsed() && can_create) {
300     ModuleSP module_sp = CalculateSymbolContextModule();
301     if (module_sp) {
302       module_sp->GetSymbolFile()->ParseBlocksRecursive(*this);
303     } else {
304       Host::SystemLog(Host::eSystemLogError,
305                       "error: unable to find module "
306                       "shared pointer for function '%s' "
307                       "in %s\n",
308                       GetName().GetCString(), m_comp_unit->GetPath().c_str());
309     }
310     m_block.SetBlockInfoHasBeenParsed(true, true);
311   }
312   return m_block;
313 }
314 
315 CompileUnit *Function::GetCompileUnit() { return m_comp_unit; }
316 
317 const CompileUnit *Function::GetCompileUnit() const { return m_comp_unit; }
318 
319 void Function::GetDescription(Stream *s, lldb::DescriptionLevel level,
320                               Target *target) {
321   ConstString name = GetName();
322   ConstString mangled = m_mangled.GetMangledName();
323 
324   *s << "id = " << (const UserID &)*this;
325   if (name)
326     *s << ", name = \"" << name.GetCString() << '"';
327   if (mangled)
328     *s << ", mangled = \"" << mangled.GetCString() << '"';
329   *s << ", range = ";
330   Address::DumpStyle fallback_style;
331   if (level == eDescriptionLevelVerbose)
332     fallback_style = Address::DumpStyleModuleWithFileAddress;
333   else
334     fallback_style = Address::DumpStyleFileAddress;
335   GetAddressRange().Dump(s, target, Address::DumpStyleLoadAddress,
336                          fallback_style);
337 }
338 
339 void Function::Dump(Stream *s, bool show_context) const {
340   s->Printf("%p: ", static_cast<const void *>(this));
341   s->Indent();
342   *s << "Function" << static_cast<const UserID &>(*this);
343 
344   m_mangled.Dump(s);
345 
346   if (m_type)
347     s->Printf(", type = %p", static_cast<void *>(m_type));
348   else if (m_type_uid != LLDB_INVALID_UID)
349     s->Printf(", type_uid = 0x%8.8" PRIx64, m_type_uid);
350 
351   s->EOL();
352   // Dump the root object
353   if (m_block.BlockInfoHasBeenParsed())
354     m_block.Dump(s, m_range.GetBaseAddress().GetFileAddress(), INT_MAX,
355                  show_context);
356 }
357 
358 void Function::CalculateSymbolContext(SymbolContext *sc) {
359   sc->function = this;
360   m_comp_unit->CalculateSymbolContext(sc);
361 }
362 
363 ModuleSP Function::CalculateSymbolContextModule() {
364   SectionSP section_sp(m_range.GetBaseAddress().GetSection());
365   if (section_sp)
366     return section_sp->GetModule();
367 
368   return this->GetCompileUnit()->GetModule();
369 }
370 
371 CompileUnit *Function::CalculateSymbolContextCompileUnit() {
372   return this->GetCompileUnit();
373 }
374 
375 Function *Function::CalculateSymbolContextFunction() { return this; }
376 
377 lldb::DisassemblerSP Function::GetInstructions(const ExecutionContext &exe_ctx,
378                                                const char *flavor,
379                                                bool prefer_file_cache) {
380   ModuleSP module_sp(GetAddressRange().GetBaseAddress().GetModule());
381   if (module_sp) {
382     const bool prefer_file_cache = false;
383     return Disassembler::DisassembleRange(module_sp->GetArchitecture(), nullptr,
384                                           flavor, exe_ctx, GetAddressRange(),
385                                           prefer_file_cache);
386   }
387   return lldb::DisassemblerSP();
388 }
389 
390 bool Function::GetDisassembly(const ExecutionContext &exe_ctx,
391                               const char *flavor, bool prefer_file_cache,
392                               Stream &strm) {
393   lldb::DisassemblerSP disassembler_sp =
394       GetInstructions(exe_ctx, flavor, prefer_file_cache);
395   if (disassembler_sp) {
396     const bool show_address = true;
397     const bool show_bytes = false;
398     disassembler_sp->GetInstructionList().Dump(&strm, show_address, show_bytes,
399                                                &exe_ctx);
400     return true;
401   }
402   return false;
403 }
404 
405 // Symbol *
406 // Function::CalculateSymbolContextSymbol ()
407 //{
408 //    return // TODO: find the symbol for the function???
409 //}
410 
411 void Function::DumpSymbolContext(Stream *s) {
412   m_comp_unit->DumpSymbolContext(s);
413   s->Printf(", Function{0x%8.8" PRIx64 "}", GetID());
414 }
415 
416 size_t Function::MemorySize() const {
417   size_t mem_size = sizeof(Function) + m_block.MemorySize();
418   return mem_size;
419 }
420 
421 bool Function::GetIsOptimized() {
422   bool result = false;
423 
424   // Currently optimization is only indicted by the vendor extension
425   // DW_AT_APPLE_optimized which is set on a compile unit level.
426   if (m_comp_unit) {
427     result = m_comp_unit->GetIsOptimized();
428   }
429   return result;
430 }
431 
432 bool Function::IsTopLevelFunction() {
433   bool result = false;
434 
435   if (Language *language = Language::FindPlugin(GetLanguage()))
436     result = language->IsTopLevelFunction(*this);
437 
438   return result;
439 }
440 
441 ConstString Function::GetDisplayName() const {
442   return m_mangled.GetDisplayDemangledName(GetLanguage());
443 }
444 
445 CompilerDeclContext Function::GetDeclContext() {
446   ModuleSP module_sp = CalculateSymbolContextModule();
447 
448   if (module_sp) {
449     if (SymbolFile *sym_file = module_sp->GetSymbolFile())
450       return sym_file->GetDeclContextForUID(GetID());
451   }
452   return CompilerDeclContext();
453 }
454 
455 Type *Function::GetType() {
456   if (m_type == nullptr) {
457     SymbolContext sc;
458 
459     CalculateSymbolContext(&sc);
460 
461     if (!sc.module_sp)
462       return nullptr;
463 
464     SymbolFile *sym_file = sc.module_sp->GetSymbolFile();
465 
466     if (sym_file == nullptr)
467       return nullptr;
468 
469     m_type = sym_file->ResolveTypeUID(m_type_uid);
470   }
471   return m_type;
472 }
473 
474 const Type *Function::GetType() const { return m_type; }
475 
476 CompilerType Function::GetCompilerType() {
477   Type *function_type = GetType();
478   if (function_type)
479     return function_type->GetFullCompilerType();
480   return CompilerType();
481 }
482 
483 uint32_t Function::GetPrologueByteSize() {
484   if (m_prologue_byte_size == 0 &&
485       m_flags.IsClear(flagsCalculatedPrologueSize)) {
486     m_flags.Set(flagsCalculatedPrologueSize);
487     LineTable *line_table = m_comp_unit->GetLineTable();
488     uint32_t prologue_end_line_idx = 0;
489 
490     if (line_table) {
491       LineEntry first_line_entry;
492       uint32_t first_line_entry_idx = UINT32_MAX;
493       if (line_table->FindLineEntryByAddress(GetAddressRange().GetBaseAddress(),
494                                              first_line_entry,
495                                              &first_line_entry_idx)) {
496         // Make sure the first line entry isn't already the end of the prologue
497         addr_t prologue_end_file_addr = LLDB_INVALID_ADDRESS;
498         addr_t line_zero_end_file_addr = LLDB_INVALID_ADDRESS;
499 
500         if (first_line_entry.is_prologue_end) {
501           prologue_end_file_addr =
502               first_line_entry.range.GetBaseAddress().GetFileAddress();
503           prologue_end_line_idx = first_line_entry_idx;
504         } else {
505           // Check the first few instructions and look for one that has
506           // is_prologue_end set to true.
507           const uint32_t last_line_entry_idx = first_line_entry_idx + 6;
508           for (uint32_t idx = first_line_entry_idx + 1;
509                idx < last_line_entry_idx; ++idx) {
510             LineEntry line_entry;
511             if (line_table->GetLineEntryAtIndex(idx, line_entry)) {
512               if (line_entry.is_prologue_end) {
513                 prologue_end_file_addr =
514                     line_entry.range.GetBaseAddress().GetFileAddress();
515                 prologue_end_line_idx = idx;
516                 break;
517               }
518             }
519           }
520         }
521 
522         // If we didn't find the end of the prologue in the line tables, then
523         // just use the end address of the first line table entry
524         if (prologue_end_file_addr == LLDB_INVALID_ADDRESS) {
525           // Check the first few instructions and look for one that has a line
526           // number that's different than the first entry.
527           uint32_t last_line_entry_idx = first_line_entry_idx + 6;
528           for (uint32_t idx = first_line_entry_idx + 1;
529                idx < last_line_entry_idx; ++idx) {
530             LineEntry line_entry;
531             if (line_table->GetLineEntryAtIndex(idx, line_entry)) {
532               if (line_entry.line != first_line_entry.line) {
533                 prologue_end_file_addr =
534                     line_entry.range.GetBaseAddress().GetFileAddress();
535                 prologue_end_line_idx = idx;
536                 break;
537               }
538             }
539           }
540 
541           if (prologue_end_file_addr == LLDB_INVALID_ADDRESS) {
542             prologue_end_file_addr =
543                 first_line_entry.range.GetBaseAddress().GetFileAddress() +
544                 first_line_entry.range.GetByteSize();
545             prologue_end_line_idx = first_line_entry_idx;
546           }
547         }
548 
549         const addr_t func_start_file_addr =
550             m_range.GetBaseAddress().GetFileAddress();
551         const addr_t func_end_file_addr =
552             func_start_file_addr + m_range.GetByteSize();
553 
554         // Now calculate the offset to pass the subsequent line 0 entries.
555         uint32_t first_non_zero_line = prologue_end_line_idx;
556         while (true) {
557           LineEntry line_entry;
558           if (line_table->GetLineEntryAtIndex(first_non_zero_line,
559                                               line_entry)) {
560             if (line_entry.line != 0)
561               break;
562           }
563           if (line_entry.range.GetBaseAddress().GetFileAddress() >=
564               func_end_file_addr)
565             break;
566 
567           first_non_zero_line++;
568         }
569 
570         if (first_non_zero_line > prologue_end_line_idx) {
571           LineEntry first_non_zero_entry;
572           if (line_table->GetLineEntryAtIndex(first_non_zero_line,
573                                               first_non_zero_entry)) {
574             line_zero_end_file_addr =
575                 first_non_zero_entry.range.GetBaseAddress().GetFileAddress();
576           }
577         }
578 
579         // Verify that this prologue end file address in the function's address
580         // range just to be sure
581         if (func_start_file_addr < prologue_end_file_addr &&
582             prologue_end_file_addr < func_end_file_addr) {
583           m_prologue_byte_size = prologue_end_file_addr - func_start_file_addr;
584         }
585 
586         if (prologue_end_file_addr < line_zero_end_file_addr &&
587             line_zero_end_file_addr < func_end_file_addr) {
588           m_prologue_byte_size +=
589               line_zero_end_file_addr - prologue_end_file_addr;
590         }
591       }
592     }
593   }
594 
595   return m_prologue_byte_size;
596 }
597 
598 lldb::LanguageType Function::GetLanguage() const {
599   lldb::LanguageType lang = m_mangled.GuessLanguage();
600   if (lang != lldb::eLanguageTypeUnknown)
601     return lang;
602 
603   if (m_comp_unit)
604     return m_comp_unit->GetLanguage();
605 
606   return lldb::eLanguageTypeUnknown;
607 }
608 
609 ConstString Function::GetName() const {
610   LanguageType language = lldb::eLanguageTypeUnknown;
611   if (m_comp_unit)
612     language = m_comp_unit->GetLanguage();
613   return m_mangled.GetName(language);
614 }
615 
616 ConstString Function::GetNameNoArguments() const {
617   LanguageType language = lldb::eLanguageTypeUnknown;
618   if (m_comp_unit)
619     language = m_comp_unit->GetLanguage();
620   return m_mangled.GetName(language, Mangled::ePreferDemangledWithoutArguments);
621 }
622