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