Refactor duplicated code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214328 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/Analysis.h

@@ -97,6 +97,13 @@ bool returnTypeIsEligibleForTailCall(const Function *F,
                                      const ReturnInst *Ret,
                                      const TargetLoweringBase &TLI);
 
+// True if GV can be left out of the object symbol table. This is the case
+// for linkonce_odr values whose address is not significant. While legal, it is
+// not normally profitable to omit them from the .o symbol table. Using this
+// analysis makes sense when the information can be passed down to the linker
+// or we are in LTO.
+bool canBeOmittedFromSymbolTable(const GlobalValue *GV);
+
 } // End llvm namespace
 
 #endif

lib/CodeGen/Analysis.cpp

@@ -25,6 +25,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetLowering.h"
+#include "llvm/Transforms/Utils/GlobalStatus.h"
 using namespace llvm;
 
 /// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
@@ -606,3 +607,29 @@ bool llvm::returnTypeIsEligibleForTailCall(const Function *F,
 
   return true;
 }
+
+bool llvm::canBeOmittedFromSymbolTable(const GlobalValue *GV) {
+  if (!GV->hasLinkOnceODRLinkage())
+    return false;
+
+  if (GV->hasUnnamedAddr())
+    return true;
+
+  // If it is a non constant variable, it needs to be uniqued across shared
+  // objects.
+  if (const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV)) {
+    if (!Var->isConstant())
+      return false;
+  }
+
+  // An alias can point to a variable. We could try to resolve the alias to
+  // decide, but for now just don't hide them.
+  if (isa<GlobalAlias>(GV))
+    return false;
+
+  GlobalStatus GS;
+  if (GlobalStatus::analyzeGlobal(GV, GS))
+    return false;
+
+  return !GS.IsCompared;
+}

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -19,6 +19,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/JumpInstrTableInfo.h"
+#include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/GCMetadataPrinter.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -49,7 +50,6 @@
 #include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
-#include "llvm/Transforms/Utils/GlobalStatus.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "asm-printer"
@@ -253,32 +253,10 @@ bool AsmPrinter::doInitialization(Module &M) {
 }
 
 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
-  if (!GV->hasLinkOnceODRLinkage())
-    return false;
-
   if (!MAI.hasWeakDefCanBeHiddenDirective())
     return false;
 
-  if (GV->hasUnnamedAddr())
-    return true;
-
-  // This is only used for MachO, so right now it doesn't really matter how
-  // we handle alias. Revisit this once the MachO linker implements aliases.
-  if (isa<GlobalAlias>(GV))
-    return false;
-
-  // If it is a non constant variable, it needs to be uniqued across shared
-  // objects.
-  if (const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV)) {
-    if (!Var->isConstant())
-      return false;
-  }
-
-  GlobalStatus GS;
-  if (!GlobalStatus::analyzeGlobal(GV, GS) && !GS.IsCompared)
-    return true;
-
-  return false;
+  return canBeOmittedFromSymbolTable(GV);
 }
 
 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {

lib/LTO/LTOModule.cpp

@@ -15,6 +15,7 @@
 #include "llvm/LTO/LTOModule.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/CodeGen/Analysis.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Metadata.h"
@@ -347,28 +348,6 @@ void LTOModule::addDefinedFunctionSymbol(const char *Name, const Function *F) {
   addDefinedSymbol(Name, F, true);
 }
 
-static bool canBeHidden(const GlobalValue *GV) {
-  // FIXME: this is duplicated with another static function in AsmPrinter.cpp
-  if (!GV->hasLinkOnceODRLinkage())
-    return false;
-
-  if (GV->hasUnnamedAddr())
-    return true;
-
-  // If it is a non constant variable, it needs to be uniqued across shared
-  // objects.
-  if (const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV)) {
-    if (!Var->isConstant())
-      return false;
-  }
-
-  GlobalStatus GS;
-  if (GlobalStatus::analyzeGlobal(GV, GS))
-    return false;
-
-  return !GS.IsCompared;
-}
-
 void LTOModule::addDefinedSymbol(const char *Name, const GlobalValue *def,
                                  bool isFunction) {
   // set alignment part log2() can have rounding errors
@@ -402,7 +381,7 @@ void LTOModule::addDefinedSymbol(const char *Name, const GlobalValue *def,
     attr |= LTO_SYMBOL_SCOPE_HIDDEN;
   else if (def->hasProtectedVisibility())
     attr |= LTO_SYMBOL_SCOPE_PROTECTED;
-  else if (canBeHidden(def))
+  else if (canBeOmittedFromSymbolTable(def))
     attr |= LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN;
   else
     attr |= LTO_SYMBOL_SCOPE_DEFAULT;