1 //===-ThinLTOCodeGenerator.cpp - LLVM Link Time Optimizer -----------------===//
8 //===----------------------------------------------------------------------===//
13 //===----------------------------------------------------------------------===//
46 #include "llvm/Transforms/IPO.h"
47 #include "llvm/Transforms/IPO/FunctionImport.h"
48 #include "llvm/Transforms/IPO/Internalize.h"
49 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
50 #include "llvm/Transforms/ObjCARC.h"
51 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
60 // Flags -discard-value-names, defined in LTOCodeGenerator.cpp
75 // Simple helper to save temporary files for debug.
76 static void saveTempBitcode(const Module &TheModule, StringRef TempDir,  in saveTempBitcode()
95         auto Linkage = Summary->linkage();  in getFirstDefinitionForLinker()
100     return StrongDefForLinker->get();  in getFirstDefinitionForLinker()
105         auto Linkage = Summary->linkage();  in getFirstDefinitionForLinker()
111   return FirstDefForLinker->get();  in getFirstDefinitionForLinker()
142 static void promoteModule(Module &TheModule, const ModuleSummaryIndex &Index) {  in promoteModule()
148 crossImportIntoModule(Module &TheModule, const ModuleSummaryIndex &Index,  in crossImportIntoModule()
156 static void optimizeModule(Module &TheModule, TargetMachine &TM) {  in optimizeModule()
194 std::unique_ptr<MemoryBuffer> codegenModule(Module &TheModule,  in codegenModule()
218 /// Manage caching for a single Module.
223   // Create a cache entry. This compute a unique hash for the Module considering
237     // This is based on the current compiler version, the module itself, the  in ModuleCacheEntry()
238     // export list, the hash for every single module in the import list, the  in ModuleCacheEntry()
239     // list of ResolvedODR for the module, and the list of preserved symbols.  in ModuleCacheEntry()
249     // Include the hash for the current module  in ModuleCacheEntry()
256     // Include the hash for every module we import functions from  in ModuleCacheEntry()
307       OS << OutputBuffer->getBuffer();  in write()
317       OS << OutputBuffer->getBuffer();  in write()
331 ProcessThinLTOModule(Module &TheModule, ModuleSummaryIndex &Index,  in ProcessThinLTOModule()
341   // "Benchmark"-like optimization: single-source case  in ProcessThinLTOModule()
347     // Apply summary-based LinkOnce/Weak resolution decisions.  in ProcessThinLTOModule()
354   // Be friendly and don't nuke totally the module when the client didn't  in ProcessThinLTOModule()
357     // Apply summary-based internalization decisions.  in ProcessThinLTOModule()
367     // Save temps: after cross-module import.  in ProcessThinLTOModule()
392 /// at least one copy kept) and a compile-time optimization (to drop duplicate
407     return Prevailing->second == S;  in resolveWeakForLinkerInIndex()
440     // First module added, so initialize the triple and some options  in addModule()
462   // we're conservatively considering cross-references as preserved.  in crossReferenceSymbol()
480   return std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(  in create()
487  * "thin-link".
502     auto Index = (*ObjOrErr)->takeIndex();  in linkCombinedIndex()
504       CombinedIndex->mergeFrom(std::move(Index), ++NextModuleId);  in linkCombinedIndex()
516 void ThinLTOCodeGenerator::promote(Module &TheModule,  in promote()
520   // Collect for each module the list of function it defines (GUID -> Summary).  in promote()
541  * Perform cross-module importing for the module identified by ModuleIdentifier.
543 void ThinLTOCodeGenerator::crossModuleImport(Module &TheModule,  in crossModuleImport()
548   // Collect for each module the list of function it defines (GUID -> Summary).  in crossModuleImport()
563  * Compute the list of summaries needed for importing into module.
570   // Collect for each module the list of function it defines (GUID -> Summary).  in gatherImportedSummariesForModule()
586  * Emit the list of files needed for importing into module.
593   // Collect for each module the list of function it defines (GUID -> Summary).  in emitImports()
612 void ThinLTOCodeGenerator::internalize(Module &TheModule,  in internalize()
622   // Collect for each module the list of function it defines (GUID -> Summary).  in internalize()
633   // Be friendly and don't nuke totally the module when the client didn't  in internalize()
642             ExportList->second.count(GUID)) ||  in internalize()
651  * Perform post-importing ThinLTO optimizations.
653 void ThinLTOCodeGenerator::optimize(Module &TheModule) {  in optimize()
663 std::unique_ptr<MemoryBuffer> ThinLTOCodeGenerator::codegen(Module &TheModule) {  in codegen()
681         // Parse module now  in run()
710   // Prepare the module map.  in run()
714   // Collect for each module the list of function it defines (GUID -> Summary).  in run()
716   Index->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);  in run()
718   // Collect the import/export lists for all modules from the call-graph in the  in run()
743             ExportList->second.count(GUID)) ||  in run()
747   // Use global summary-based analysis to identify symbols that can be  in run()
752   // Make sure that every module has an entry in the ExportLists and  in run()
760   // is to sort them per size so that the largest module get schedule as soon as  in run()
761   // possible. This is purely a compile-time optimization.  in run()
783         // The module may be cached, this helps handling it.  in run()
806         // Parse module now  in run()