1 //===- Analysis/ObjectUtils.h - analysis utils for object files -*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef LLVM_ANALYSIS_OBJECT_UTILS_H 11 #define LLVM_ANALYSIS_OBJECT_UTILS_H 12 13 #include "llvm/IR/GlobalVariable.h" 14 15 namespace llvm { 16 17 /// True if GV can be left out of the object symbol table. This is the case 18 /// for linkonce_odr values whose address is not significant. While legal, it is 19 /// not normally profitable to omit them from the .o symbol table. Using this 20 /// analysis makes sense when the information can be passed down to the linker 21 /// or we are in LTO. 22 inline bool canBeOmittedFromSymbolTable(const GlobalValue *GV) { 23 if (!GV->hasLinkOnceODRLinkage()) 24 return false; 25 26 // We assume that anyone who sets global unnamed_addr on a non-constant knows 27 // what they're doing. 28 if (GV->hasGlobalUnnamedAddr()) 29 return true; 30 31 // If it is a non constant variable, it needs to be uniqued across shared 32 // objects. 33 if (auto *Var = dyn_cast<GlobalVariable>(GV)) 34 if (!Var->isConstant()) 35 return false; 36 37 return GV->hasAtLeastLocalUnnamedAddr(); 38 } 39 40 } 41 42 #endif 43
