[x86] Hoist the logic for extracting the relevant bits of information

[oota-llvm.git] / lib / IR / Globals.cpp

diff --git a/lib/IR/Globals.cpp b/lib/IR/Globals.cpp
index 8e7478496f07ab6fb41b3b215d05f7712068812c..244e3e4baeedc6c1f5e7d95b9eb34943cf08885b 100644 (file)
--- a/lib/IR/Globals.cpp
+++ b/lib/IR/Globals.cpp
@@ -20,6 +20,7 @@
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/LeakDetector.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/Operator.h"
 #include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
@@ -59,9 +60,16 @@ void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
 }
 
 unsigned GlobalValue::getAlignment() const {
-  if (auto *GA = dyn_cast<GlobalAlias>(this))
-    return GA->getAliasedGlobal()->getAlignment();
-
+  if (auto *GA = dyn_cast<GlobalAlias>(this)) {
+    // In general we cannot compute this at the IR level, but we try.
+    if (const GlobalObject *GO = GA->getBaseObject())
+      return GO->getAlignment();
+
+    // FIXME: we should also be able to handle:
+    // Alias = Global + Offset
+    // Alias = Absolute
+    return 0;
+  }
   return cast<GlobalObject>(this)->getAlignment();
 }
 
@@ -80,12 +88,26 @@ void GlobalObject::copyAttributesFrom(const GlobalValue *Src) {
   setSection(GV->getSection());
 }
 
-const std::string &GlobalValue::getSection() const {
-  if (auto *GA = dyn_cast<GlobalAlias>(this))
-    return GA->getAliasedGlobal()->getSection();
+const char *GlobalValue::getSection() const {
+  if (auto *GA = dyn_cast<GlobalAlias>(this)) {
+    // In general we cannot compute this at the IR level, but we try.
+    if (const GlobalObject *GO = GA->getBaseObject())
+      return GO->getSection();
+    return "";
+  }
   return cast<GlobalObject>(this)->getSection();
 }
 
+Comdat *GlobalValue::getComdat() {
+  if (auto *GA = dyn_cast<GlobalAlias>(this)) {
+    // In general we cannot compute this at the IR level, but we try.
+    if (const GlobalObject *GO = GA->getBaseObject())
+      return const_cast<GlobalObject *>(GO)->getComdat();
+    return nullptr;
+  }
+  return cast<GlobalObject>(this)->getComdat();
+}
+
 void GlobalObject::setSection(StringRef S) { Section = S; }
 
 bool GlobalValue::isDeclaration() const {
@@ -113,8 +135,9 @@ GlobalVariable::GlobalVariable(Type *Ty, bool constant, LinkageTypes Link,
     : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
                    OperandTraits<GlobalVariable>::op_begin(this),
                    InitVal != nullptr, Link, Name),
-      isConstantGlobal(constant), threadLocalMode(TLMode),
+      isConstantGlobal(constant),
       isExternallyInitializedConstant(isExternallyInitialized) {
+  setThreadLocalMode(TLMode);
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
@@ -132,8 +155,9 @@ GlobalVariable::GlobalVariable(Module &M, Type *Ty, bool constant,
     : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
                    OperandTraits<GlobalVariable>::op_begin(this),
                    InitVal != nullptr, Link, Name),
-      isConstantGlobal(constant), threadLocalMode(TLMode),
+      isConstantGlobal(constant),
       isExternallyInitializedConstant(isExternallyInitialized) {
+  setThreadLocalMode(TLMode);
   if (InitVal) {
     assert(InitVal->getType() == Ty &&
            "Initializer should be the same type as the GlobalVariable!");
@@ -213,22 +237,47 @@ void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
 // GlobalAlias Implementation
 //===----------------------------------------------------------------------===//
 
-GlobalAlias::GlobalAlias(Type *Ty, LinkageTypes Link, const Twine &Name,
-                         Constant *Aliasee, Module *ParentModule,
-                         unsigned AddressSpace)
+GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
+                         const Twine &Name, Constant *Aliasee,
+                         Module *ParentModule)
     : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalAliasVal,
                   &Op<0>(), 1, Link, Name) {
   LeakDetector::addGarbageObject(this);
-
-  if (Aliasee)
-    assert(Aliasee->getType() == getType() &&
-           "Alias and aliasee types should match!");
   Op<0>() = Aliasee;
 
   if (ParentModule)
     ParentModule->getAliasList().push_back(this);
 }
 
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Link, const Twine &Name,
+                                 Constant *Aliasee, Module *ParentModule) {
+  return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
+}
+
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Linkage, const Twine &Name,
+                                 Module *Parent) {
+  return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
+}
+
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+                                 LinkageTypes Linkage, const Twine &Name,
+                                 GlobalValue *Aliasee) {
+  return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
+}
+
+GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
+                                 GlobalValue *Aliasee) {
+  PointerType *PTy = Aliasee->getType();
+  return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name,
+                Aliasee);
+}
+
+GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) {
+  return create(Aliasee->getLinkage(), Name, Aliasee);
+}
+
 void GlobalAlias::setParent(Module *parent) {
   if (getParent())
     LeakDetector::addGarbageObject(this);
@@ -248,39 +297,5 @@ void GlobalAlias::eraseFromParent() {
 void GlobalAlias::setAliasee(Constant *Aliasee) {
   assert((!Aliasee || Aliasee->getType() == getType()) &&
          "Alias and aliasee types should match!");
-
   setOperand(0, Aliasee);
 }
-
-static GlobalValue *getAliaseeGV(GlobalAlias *GA) {
-  Constant *C = GA->getAliasee();
-  assert(C && "Must alias something");
-
-  if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
-    return GV;
-
-  ConstantExpr *CE = cast<ConstantExpr>(C);
-  assert((CE->getOpcode() == Instruction::BitCast ||
-          CE->getOpcode() == Instruction::AddrSpaceCast ||
-          CE->getOpcode() == Instruction::GetElementPtr) &&
-         "Unsupported aliasee");
-
-  return cast<GlobalValue>(CE->getOperand(0));
-}
-
-GlobalObject *GlobalAlias::getAliasedGlobal() {
-  SmallPtrSet<GlobalValue*, 3> Visited;
-
-  GlobalAlias *GA = this;
-
-  for (;;) {
-    GlobalValue *GV = getAliaseeGV(GA);
-    if (!Visited.insert(GV))
-      return nullptr;
-
-    // Iterate over aliasing chain.
-    GA = dyn_cast<GlobalAlias>(GV);
-    if (!GA)
-      return cast<GlobalObject>(GV);
-  }
-}