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,
63                                        llvm::StringRef mangled,
64                                        const Declaration *decl_ptr,
65                                        const Declaration *call_decl_ptr)
66     : FunctionInfo(name, decl_ptr), m_mangled(mangled),
67       m_call_decl(call_decl_ptr) {}
68 
69 InlineFunctionInfo::InlineFunctionInfo(ConstString name,
70                                        const Mangled &mangled,
71                                        const Declaration *decl_ptr,
72                                        const Declaration *call_decl_ptr)
73     : FunctionInfo(name, decl_ptr), m_mangled(mangled),
74       m_call_decl(call_decl_ptr) {}
75 
76 InlineFunctionInfo::~InlineFunctionInfo() {}
77 
78 int InlineFunctionInfo::Compare(const InlineFunctionInfo &a,
79                                 const InlineFunctionInfo &b) {
80 
81   int result = FunctionInfo::Compare(a, b);
82   if (result)
83     return result;
84   // only compare the mangled names if both have them
85   return Mangled::Compare(a.m_mangled, a.m_mangled);
86 }
87 
88 void InlineFunctionInfo::Dump(Stream *s, bool show_fullpaths) const {
89   FunctionInfo::Dump(s, show_fullpaths);
90   if (m_mangled)
91     m_mangled.Dump(s);
92 }
93 
94 void InlineFunctionInfo::DumpStopContext(Stream *s,
95                                          LanguageType language) const {
96   //    s->Indent("[inlined] ");
97   s->Indent();
98   if (m_mangled)
99     s->PutCString(m_mangled.GetName(language).AsCString());
100   else
101     s->PutCString(m_name.AsCString());
102 }
103 
104 ConstString InlineFunctionInfo::GetName(LanguageType language) const {
105   if (m_mangled)
106     return m_mangled.GetName(language);
107   return m_name;
108 }
109 
110 ConstString InlineFunctionInfo::GetDisplayName(LanguageType language) const {
111   if (m_mangled)
112     return m_mangled.GetDisplayDemangledName(language);
113   return m_name;
114 }
115 
116 Declaration &InlineFunctionInfo::GetCallSite() { return m_call_decl; }
117 
118 const Declaration &InlineFunctionInfo::GetCallSite() const {
119   return m_call_decl;
120 }
121 
122 Mangled &InlineFunctionInfo::GetMangled() { return m_mangled; }
123 
124 const Mangled &InlineFunctionInfo::GetMangled() const { return m_mangled; }
125 
126 size_t InlineFunctionInfo::MemorySize() const {
127   return FunctionInfo::MemorySize() + m_mangled.MemorySize();
128 }
129 
130 //
131 CallEdge::CallEdge(const char *symbol_name, lldb::addr_t return_pc,
132                    CallSiteParameterArray parameters)
133     : return_pc(return_pc), parameters(std::move(parameters)), resolved(false) {
134   lazy_callee.symbol_name = symbol_name;
135 }
136 
137 llvm::ArrayRef<CallSiteParameter> CallEdge::GetCallSiteParameters() const {
138   return parameters;
139 }
140 
141 void CallEdge::ParseSymbolFileAndResolve(ModuleList &images) {
142   if (resolved)
143     return;
144 
145   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
146   LLDB_LOG(log, "CallEdge: Lazily parsing the call graph for {0}",
147            lazy_callee.symbol_name);
148 
149   auto resolve_lazy_callee = [&]() -> Function * {
150     ConstString callee_name{lazy_callee.symbol_name};
151     SymbolContextList sc_list;
152     images.FindFunctionSymbols(callee_name, eFunctionNameTypeAuto, sc_list);
153     size_t num_matches = sc_list.GetSize();
154     if (num_matches == 0 || !sc_list[0].symbol) {
155       LLDB_LOG(log, "CallEdge: Found no symbols for {0}, cannot resolve it",
156                callee_name);
157       return nullptr;
158     }
159     Address callee_addr = sc_list[0].symbol->GetAddress();
160     if (!callee_addr.IsValid()) {
161       LLDB_LOG(log, "CallEdge: Invalid symbol address");
162       return nullptr;
163     }
164     Function *f = callee_addr.CalculateSymbolContextFunction();
165     if (!f) {
166       LLDB_LOG(log, "CallEdge: Could not find complete function");
167       return nullptr;
168     }
169     return f;
170   };
171   lazy_callee.def = resolve_lazy_callee();
172   resolved = true;
173 }
174 
175 Function *CallEdge::GetCallee(ModuleList &images) {
176   ParseSymbolFileAndResolve(images);
177   assert(resolved && "Did not resolve lazy callee");
178   return lazy_callee.def;
179 }
180 
181 lldb::addr_t CallEdge::GetReturnPCAddress(Function &caller,
182                                           Target &target) const {
183   const Address &base = caller.GetAddressRange().GetBaseAddress();
184   return base.GetLoadAddress(&target) + return_pc;
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(), 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 CallEdge *Function::GetCallEdgeForReturnAddress(addr_t return_pc,
287                                                 Target &target) {
288   auto edges = GetCallEdges();
289   auto edge_it =
290       std::lower_bound(edges.begin(), edges.end(), return_pc,
291                        [&](const CallEdge &edge, addr_t pc) {
292                          return edge.GetReturnPCAddress(*this, target) < pc;
293                        });
294   if (edge_it == edges.end() ||
295       edge_it->GetReturnPCAddress(*this, target) != return_pc)
296     return nullptr;
297   return &const_cast<CallEdge &>(*edge_it);
298 }
299 
300 Block &Function::GetBlock(bool can_create) {
301   if (!m_block.BlockInfoHasBeenParsed() && can_create) {
302     ModuleSP module_sp = CalculateSymbolContextModule();
303     if (module_sp) {
304       module_sp->GetSymbolFile()->ParseBlocksRecursive(*this);
305     } else {
306       Host::SystemLog(Host::eSystemLogError,
307                       "error: unable to find module "
308                       "shared pointer for function '%s' "
309                       "in %s\n",
310                       GetName().GetCString(), m_comp_unit->GetPath().c_str());
311     }
312     m_block.SetBlockInfoHasBeenParsed(true, true);
313   }
314   return m_block;
315 }
316 
317 CompileUnit *Function::GetCompileUnit() { return m_comp_unit; }
318 
319 const CompileUnit *Function::GetCompileUnit() const { return m_comp_unit; }
320 
321 void Function::GetDescription(Stream *s, lldb::DescriptionLevel level,
322                               Target *target) {
323   ConstString name = GetName();
324   ConstString mangled = m_mangled.GetMangledName();
325 
326   *s << "id = " << (const UserID &)*this;
327   if (name)
328     *s << ", name = \"" << name.GetCString() << '"';
329   if (mangled)
330     *s << ", mangled = \"" << mangled.GetCString() << '"';
331   *s << ", range = ";
332   Address::DumpStyle fallback_style;
333   if (level == eDescriptionLevelVerbose)
334     fallback_style = Address::DumpStyleModuleWithFileAddress;
335   else
336     fallback_style = Address::DumpStyleFileAddress;
337   GetAddressRange().Dump(s, target, Address::DumpStyleLoadAddress,
338                          fallback_style);
339 }
340 
341 void Function::Dump(Stream *s, bool show_context) const {
342   s->Printf("%p: ", static_cast<const void *>(this));
343   s->Indent();
344   *s << "Function" << static_cast<const UserID &>(*this);
345 
346   m_mangled.Dump(s);
347 
348   if (m_type)
349     s->Printf(", type = %p", static_cast<void *>(m_type));
350   else if (m_type_uid != LLDB_INVALID_UID)
351     s->Printf(", type_uid = 0x%8.8" PRIx64, m_type_uid);
352 
353   s->EOL();
354   // Dump the root object
355   if (m_block.BlockInfoHasBeenParsed())
356     m_block.Dump(s, m_range.GetBaseAddress().GetFileAddress(), INT_MAX,
357                  show_context);
358 }
359 
360 void Function::CalculateSymbolContext(SymbolContext *sc) {
361   sc->function = this;
362   m_comp_unit->CalculateSymbolContext(sc);
363 }
364 
365 ModuleSP Function::CalculateSymbolContextModule() {
366   SectionSP section_sp(m_range.GetBaseAddress().GetSection());
367   if (section_sp)
368     return section_sp->GetModule();
369 
370   return this->GetCompileUnit()->GetModule();
371 }
372 
373 CompileUnit *Function::CalculateSymbolContextCompileUnit() {
374   return this->GetCompileUnit();
375 }
376 
377 Function *Function::CalculateSymbolContextFunction() { return this; }
378 
379 lldb::DisassemblerSP Function::GetInstructions(const ExecutionContext &exe_ctx,
380                                                const char *flavor,
381                                                bool prefer_file_cache) {
382   ModuleSP module_sp(GetAddressRange().GetBaseAddress().GetModule());
383   if (module_sp) {
384     const bool prefer_file_cache = false;
385     return Disassembler::DisassembleRange(module_sp->GetArchitecture(), nullptr,
386                                           flavor, exe_ctx, GetAddressRange(),
387                                           prefer_file_cache);
388   }
389   return lldb::DisassemblerSP();
390 }
391 
392 bool Function::GetDisassembly(const ExecutionContext &exe_ctx,
393                               const char *flavor, bool prefer_file_cache,
394                               Stream &strm) {
395   lldb::DisassemblerSP disassembler_sp =
396       GetInstructions(exe_ctx, flavor, prefer_file_cache);
397   if (disassembler_sp) {
398     const bool show_address = true;
399     const bool show_bytes = false;
400     disassembler_sp->GetInstructionList().Dump(&strm, show_address, show_bytes,
401                                                &exe_ctx);
402     return true;
403   }
404   return false;
405 }
406 
407 // Symbol *
408 // Function::CalculateSymbolContextSymbol ()
409 //{
410 //    return // TODO: find the symbol for the function???
411 //}
412 
413 void Function::DumpSymbolContext(Stream *s) {
414   m_comp_unit->DumpSymbolContext(s);
415   s->Printf(", Function{0x%8.8" PRIx64 "}", GetID());
416 }
417 
418 size_t Function::MemorySize() const {
419   size_t mem_size = sizeof(Function) + m_block.MemorySize();
420   return mem_size;
421 }
422 
423 bool Function::GetIsOptimized() {
424   bool result = false;
425 
426   // Currently optimization is only indicted by the vendor extension
427   // DW_AT_APPLE_optimized which is set on a compile unit level.
428   if (m_comp_unit) {
429     result = m_comp_unit->GetIsOptimized();
430   }
431   return result;
432 }
433 
434 bool Function::IsTopLevelFunction() {
435   bool result = false;
436 
437   if (Language *language = Language::FindPlugin(GetLanguage()))
438     result = language->IsTopLevelFunction(*this);
439 
440   return result;
441 }
442 
443 ConstString Function::GetDisplayName() const {
444   return m_mangled.GetDisplayDemangledName(GetLanguage());
445 }
446 
447 CompilerDeclContext Function::GetDeclContext() {
448   ModuleSP module_sp = CalculateSymbolContextModule();
449 
450   if (module_sp) {
451     if (SymbolFile *sym_file = module_sp->GetSymbolFile())
452       return sym_file->GetDeclContextForUID(GetID());
453   }
454   return CompilerDeclContext();
455 }
456 
457 Type *Function::GetType() {
458   if (m_type == nullptr) {
459     SymbolContext sc;
460 
461     CalculateSymbolContext(&sc);
462 
463     if (!sc.module_sp)
464       return nullptr;
465 
466     SymbolFile *sym_file = sc.module_sp->GetSymbolFile();
467 
468     if (sym_file == nullptr)
469       return nullptr;
470 
471     m_type = sym_file->ResolveTypeUID(m_type_uid);
472   }
473   return m_type;
474 }
475 
476 const Type *Function::GetType() const { return m_type; }
477 
478 CompilerType Function::GetCompilerType() {
479   Type *function_type = GetType();
480   if (function_type)
481     return function_type->GetFullCompilerType();
482   return CompilerType();
483 }
484 
485 uint32_t Function::GetPrologueByteSize() {
486   if (m_prologue_byte_size == 0 &&
487       m_flags.IsClear(flagsCalculatedPrologueSize)) {
488     m_flags.Set(flagsCalculatedPrologueSize);
489     LineTable *line_table = m_comp_unit->GetLineTable();
490     uint32_t prologue_end_line_idx = 0;
491 
492     if (line_table) {
493       LineEntry first_line_entry;
494       uint32_t first_line_entry_idx = UINT32_MAX;
495       if (line_table->FindLineEntryByAddress(GetAddressRange().GetBaseAddress(),
496                                              first_line_entry,
497                                              &first_line_entry_idx)) {
498         // Make sure the first line entry isn't already the end of the prologue
499         addr_t prologue_end_file_addr = LLDB_INVALID_ADDRESS;
500         addr_t line_zero_end_file_addr = LLDB_INVALID_ADDRESS;
501 
502         if (first_line_entry.is_prologue_end) {
503           prologue_end_file_addr =
504               first_line_entry.range.GetBaseAddress().GetFileAddress();
505           prologue_end_line_idx = first_line_entry_idx;
506         } else {
507           // Check the first few instructions and look for one that has
508           // is_prologue_end set to true.
509           const uint32_t last_line_entry_idx = first_line_entry_idx + 6;
510           for (uint32_t idx = first_line_entry_idx + 1;
511                idx < last_line_entry_idx; ++idx) {
512             LineEntry line_entry;
513             if (line_table->GetLineEntryAtIndex(idx, line_entry)) {
514               if (line_entry.is_prologue_end) {
515                 prologue_end_file_addr =
516                     line_entry.range.GetBaseAddress().GetFileAddress();
517                 prologue_end_line_idx = idx;
518                 break;
519               }
520             }
521           }
522         }
523 
524         // If we didn't find the end of the prologue in the line tables, then
525         // just use the end address of the first line table entry
526         if (prologue_end_file_addr == LLDB_INVALID_ADDRESS) {
527           // Check the first few instructions and look for one that has a line
528           // number that's different than the first entry.
529           uint32_t last_line_entry_idx = first_line_entry_idx + 6;
530           for (uint32_t idx = first_line_entry_idx + 1;
531                idx < last_line_entry_idx; ++idx) {
532             LineEntry line_entry;
533             if (line_table->GetLineEntryAtIndex(idx, line_entry)) {
534               if (line_entry.line != first_line_entry.line) {
535                 prologue_end_file_addr =
536                     line_entry.range.GetBaseAddress().GetFileAddress();
537                 prologue_end_line_idx = idx;
538                 break;
539               }
540             }
541           }
542 
543           if (prologue_end_file_addr == LLDB_INVALID_ADDRESS) {
544             prologue_end_file_addr =
545                 first_line_entry.range.GetBaseAddress().GetFileAddress() +
546                 first_line_entry.range.GetByteSize();
547             prologue_end_line_idx = first_line_entry_idx;
548           }
549         }
550 
551         const addr_t func_start_file_addr =
552             m_range.GetBaseAddress().GetFileAddress();
553         const addr_t func_end_file_addr =
554             func_start_file_addr + m_range.GetByteSize();
555 
556         // Now calculate the offset to pass the subsequent line 0 entries.
557         uint32_t first_non_zero_line = prologue_end_line_idx;
558         while (true) {
559           LineEntry line_entry;
560           if (line_table->GetLineEntryAtIndex(first_non_zero_line,
561                                               line_entry)) {
562             if (line_entry.line != 0)
563               break;
564           }
565           if (line_entry.range.GetBaseAddress().GetFileAddress() >=
566               func_end_file_addr)
567             break;
568 
569           first_non_zero_line++;
570         }
571 
572         if (first_non_zero_line > prologue_end_line_idx) {
573           LineEntry first_non_zero_entry;
574           if (line_table->GetLineEntryAtIndex(first_non_zero_line,
575                                               first_non_zero_entry)) {
576             line_zero_end_file_addr =
577                 first_non_zero_entry.range.GetBaseAddress().GetFileAddress();
578           }
579         }
580 
581         // Verify that this prologue end file address in the function's address
582         // range just to be sure
583         if (func_start_file_addr < prologue_end_file_addr &&
584             prologue_end_file_addr < func_end_file_addr) {
585           m_prologue_byte_size = prologue_end_file_addr - func_start_file_addr;
586         }
587 
588         if (prologue_end_file_addr < line_zero_end_file_addr &&
589             line_zero_end_file_addr < func_end_file_addr) {
590           m_prologue_byte_size +=
591               line_zero_end_file_addr - prologue_end_file_addr;
592         }
593       }
594     }
595   }
596 
597   return m_prologue_byte_size;
598 }
599 
600 lldb::LanguageType Function::GetLanguage() const {
601   lldb::LanguageType lang = m_mangled.GuessLanguage();
602   if (lang != lldb::eLanguageTypeUnknown)
603     return lang;
604 
605   if (m_comp_unit)
606     return m_comp_unit->GetLanguage();
607 
608   return lldb::eLanguageTypeUnknown;
609 }
610 
611 ConstString Function::GetName() const {
612   LanguageType language = lldb::eLanguageTypeUnknown;
613   if (m_comp_unit)
614     language = m_comp_unit->GetLanguage();
615   return m_mangled.GetName(language);
616 }
617 
618 ConstString Function::GetNameNoArguments() const {
619   LanguageType language = lldb::eLanguageTypeUnknown;
620   if (m_comp_unit)
621     language = m_comp_unit->GetLanguage();
622   return m_mangled.GetName(language, Mangled::ePreferDemangledWithoutArguments);
623 }
624