move some classification logic around. Now GVRequiresExtraLoad

is just a trivial wrapper around "ClassifyGlobalReference", which
stole a ton of logic from LowerGlobalAddress.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75237 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 100 insertions, 74 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 28ee2c3..e3ffb29 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4553,50 +4553,20 @@ X86TargetLowering::LowerGlobalAddress(const GlobalValue *GV, DebugLoc dl,
                                       int64_t Offset,
                                       SelectionDAG &DAG) const {
   bool IsPIC = getTargetMachine().getRelocationModel() == Reloc::PIC_;
-  bool ExtraLoadRequired =
-    Subtarget->GVRequiresExtraLoad(GV, getTargetMachine());
 
   // Create the TargetGlobalAddress node, folding in the constant
   // offset if it is legal.
+  unsigned char OpFlags =
+    Subtarget->ClassifyGlobalReference(GV, getTargetMachine());
+  bool ExtraLoadRequired = isGlobalStubReference(OpFlags);
+  
+  
   SDValue Result;
   if (!IsPIC && !ExtraLoadRequired && isInt32(Offset)) {
     // A direct static reference to a global.
     Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset);
     Offset = 0;
   } else {
-    unsigned char OpFlags = 0;
-    
-    if (GV->hasDLLImportLinkage())
-      OpFlags = X86II::MO_DLLIMPORT;
-    else if (Subtarget->isPICStyleRIPRel()) {
-      if (ExtraLoadRequired)
-        OpFlags = X86II::MO_GOTPCREL;
-    } else if (Subtarget->isPICStyleGOT()) {
-      if (ExtraLoadRequired)
-        OpFlags = X86II::MO_GOT;
-      else
-        OpFlags = X86II::MO_GOTOFF;
-    } else if (Subtarget->isPICStyleStub()) {
-      // In darwin, we have multiple different stub types, and we have both PIC
-      // and -mdynamic-no-pic.  Determine whether we have a stub reference
-      // and/or whether the reference is relative to the PIC base or not.
-      
-      // Link-once, declaration, or Weakly-linked global variables need
-      // non-lazily-resolved stubs.
-      if (!ExtraLoadRequired) {
-        // Not a stub reference.
-        OpFlags = IsPIC ? X86II::MO_PIC_BASE_OFFSET : 0;
-      } else if (!GV->hasHiddenVisibility()) {
-        // Non-hidden $non_lazy_ptr reference.
-        OpFlags = IsPIC ? X86II::MO_DARWIN_NONLAZY_PIC_BASE :
-                          X86II::MO_DARWIN_NONLAZY;
-      } else {
-        // Hidden $non_lazy_ptr reference.
-        OpFlags = IsPIC ? X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE :
-                          X86II::MO_DARWIN_HIDDEN_NONLAZY;
-      }
-    }
-    
     Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), 0, OpFlags);
   }
   
diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp
index d16319b..d9c915a 100644
--- a/lib/Target/X86/X86Subtarget.cpp
+++ b/lib/Target/X86/X86Subtarget.cpp
@@ -13,6 +13,7 @@
 
 #define DEBUG_TYPE "subtarget"
 #include "X86Subtarget.h"
+#include "X86InstrInfo.h"
 #include "X86GenSubtarget.inc"
 #include "llvm/Module.h"
 #include "llvm/Support/CommandLine.h"
@@ -34,37 +35,89 @@ AsmWriterFlavor("x86-asm-syntax", cl::init(X86Subtarget::Unset),
     clEnumValEnd));
 
 
+/// ClassifyGlobalReference - Classify a global variable reference for the
+/// current subtarget according to how we should reference it in a non-pcrel
+/// context.
+unsigned char X86Subtarget::
+ClassifyGlobalReference(const GlobalValue *GV, const TargetMachine &TM) const {
+  // DLLImport only exists on windows, it is implemented as a load from a
+  // DLLIMPORT stub.
+  if (GV->hasDLLImportLinkage())
+    return X86II::MO_DLLIMPORT;
+
+  // X86-64 in PIC mode.
+  if (isPICStyleRIPRel()) {
+    // Large model never uses stubs.
+    if (TM.getCodeModel() == CodeModel::Large)
+      return X86II::MO_NO_FLAG;
+      
+      if (isTargetDarwin()) {
+        // If symbol visibility is hidden, the extra load is not needed if
+        // target is x86-64 or the symbol is definitely defined in the current
+        // translation unit.
+        if (GV->hasDefaultVisibility() &&
+            (GV->isDeclaration() || GV->isWeakForLinker()))
+          return X86II::MO_GOTPCREL;
+      } else {
+        assert(isTargetELF() && "Unknown rip-relative target");
+
+        // Extra load is needed for all externally visible.
+        if (!GV->hasLocalLinkage() && GV->hasDefaultVisibility())
+          return X86II::MO_GOTPCREL;
+      }
+
+    return X86II::MO_NO_FLAG;
+  }
+  
+  if (isPICStyleGOT()) {   // 32-bit ELF targets.
+    // Extra load is needed for all externally visible.
+    if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
+      return X86II::MO_GOTOFF;
+    return X86II::MO_GOT;
+  }
+  
+  if (isPICStyleStub()) {
+    // In Darwin/32, we have multiple different stub types, and we have both PIC
+    // and -mdynamic-no-pic.  Determine whether we have a stub reference
+    // and/or whether the reference is relative to the PIC base or not.
+    bool IsPIC = TM.getRelocationModel() == Reloc::PIC_;
+    
+    // If this is a strong reference to a definition, it is definitely not
+    // through a stub.
+    if (!GV->isDeclaration() && !GV->isWeakForLinker())
+      return IsPIC ? X86II::MO_PIC_BASE_OFFSET : 0;
+
+    // Unless we have a symbol with hidden visibility, we have to go through a
+    // normal $non_lazy_ptr stub because this symbol might be resolved late.
+    if (!GV->hasHiddenVisibility()) {
+      // Non-hidden $non_lazy_ptr reference.
+      return IsPIC ? X86II::MO_DARWIN_NONLAZY_PIC_BASE :
+                     X86II::MO_DARWIN_NONLAZY;
+    }
+    
+    // If symbol visibility is hidden, we have a stub for common symbol
+    // references and external declarations.
+    if (GV->isDeclaration() || GV->hasCommonLinkage()) {
+      // Hidden $non_lazy_ptr reference.
+      return IsPIC ? X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE :
+                     X86II::MO_DARWIN_HIDDEN_NONLAZY;
+    }
+    
+    // Otherwise, no stub.
+    return IsPIC ? X86II::MO_PIC_BASE_OFFSET : 0;
+  }
+  
+  // Direct static reference to global.
+  return X86II::MO_NO_FLAG;
+}
+
 /// True if accessing the GV requires an extra load. For Windows, dllimported
 /// symbols are indirect, loading the value at address GV rather then the
 /// value of GV itself. This means that the GlobalAddress must be in the base
 /// or index register of the address, not the GV offset field.
 bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue *GV,
                                        const TargetMachine &TM) const {
-  // Windows targets only require an extra load for DLLImport linkage values,
-  // and they need these regardless of whether we're in PIC mode or not.
-  if (isTargetCygMing() || isTargetWindows())
-    return GV->hasDLLImportLinkage();
-
-  if (TM.getRelocationModel() == Reloc::Static ||
-      TM.getCodeModel() == CodeModel::Large)
-    return false;
-    
-  if (isTargetDarwin()) {
-    bool isDecl = GV->isDeclaration() && !GV->hasNotBeenReadFromBitcode();
-    if (GV->hasHiddenVisibility() &&
-        (Is64Bit || (!isDecl && !GV->hasCommonLinkage())))
-      // If symbol visibility is hidden, the extra load is not needed if
-      // target is x86-64 or the symbol is definitely defined in the current
-      // translation unit.
-      return false;
-    return isDecl || GV->isWeakForLinker();
-  } else if (isTargetELF()) {
-    // Extra load is needed for all externally visible.
-    if (GV->hasLocalLinkage() || GV->hasHiddenVisibility())
-      return false;
-    return true;
-  }
-  return false;
+  return isGlobalStubReference(ClassifyGlobalReference(GV, TM));
 }
 
 /// True if accessing the GV requires a register.  This is a superset of the
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index 1fe612a..2990df5 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -150,7 +150,6 @@ public:
   bool hasAVX() const { return HasAVX; }
   bool hasFMA3() const { return HasFMA3; }
   bool hasFMA4() const { return HasFMA4; }
-
   bool isBTMemSlow() const { return IsBTMemSlow; }
 
   unsigned getAsmFlavor() const {
@@ -161,28 +160,25 @@ public:
   bool isFlavorIntel() const { return AsmFlavor == Intel; }
 
   bool isTargetDarwin() const { return TargetType == isDarwin; }
-  bool isTargetELF() const {
-    return TargetType == isELF;
-  }
+  bool isTargetELF() const { return TargetType == isELF; }
   bool isTargetWindows() const { return TargetType == isWindows; }
   bool isTargetMingw() const { return TargetType == isMingw; }
-  bool isTargetCygMing() const { return (TargetType == isMingw ||
-                                         TargetType == isCygwin); }
+  bool isTargetCygMing() const {
+    return TargetType == isMingw || TargetType == isCygwin;
+  }
   bool isTargetCygwin() const { return TargetType == isCygwin; }
   bool isTargetWin64() const {
-    return (Is64Bit && (TargetType == isMingw || TargetType == isWindows));
+    return Is64Bit && (TargetType == isMingw || TargetType == isWindows);
   }
 
   std::string getDataLayout() const {
     const char *p;
     if (is64Bit())
       p = "e-p:64:64-s:64-f64:64:64-i64:64:64-f80:128:128";
-    else {
-      if (isTargetDarwin())
-        p = "e-p:32:32-f64:32:64-i64:32:64-f80:128:128";
-      else
-        p = "e-p:32:32-f64:32:64-i64:32:64-f80:32:32";
-    }
+    else if (isTargetDarwin())
+      p = "e-p:32:32-f64:32:64-i64:32:64-f80:128:128";
+    else
+      p = "e-p:32:32-f64:32:64-i64:32:64-f80:32:32";
     return std::string(p);
   }
 
@@ -197,11 +193,18 @@ public:
   /// isLinux - Return true if the target is "Linux".
   bool isLinux() const { return IsLinux; }
 
+  
+  /// ClassifyGlobalReference - Classify a global variable reference for the
+  /// current subtarget according to how we should reference it in a non-pcrel
+  /// context.
+  unsigned char ClassifyGlobalReference(const GlobalValue *GV,
+                                        const TargetMachine &TM)const;
+  
   /// True if accessing the GV requires an extra load. For Windows, dllimported
   /// symbols are indirect, loading the value at address GV rather then the
   /// value of GV itself. This means that the GlobalAddress must be in the base
   /// or index register of the address, not the GV offset field.
-  bool GVRequiresExtraLoad(const GlobalValue* GV, const TargetMachine &TM)const;
+  bool GVRequiresExtraLoad(const GlobalValue *GV, const TargetMachine &TM)const;
 
   /// True if accessing the GV requires a register.  This is a superset of the
   /// cases where GVRequiresExtraLoad is true.  Some variations of PIC require