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