De-virtualize GlobalValue

The erase/remove from parent methods now use a switch table to remove
themselves from their appropriate parent ilist.

The copyAttributesFrom method is now completely non-virtual, since we
only ever copy attributes from a global of the appropriate type.

Pre-requisite to de-virtualizing Value to save a vptr
(https://reviews.llvm.org/D31261).

NFC

llvm-svn: 302823

1 files changed, 31 insertions, 11 deletions

diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index 5fbf51e0089..10ba1a64ad0 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -69,6 +69,30 @@ void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
   setDLLStorageClass(Src->getDLLStorageClass());
 }
 
+void GlobalValue::removeFromParent() {
+  switch (getValueID()) {
+#define HANDLE_GLOBAL_VALUE(NAME)                                              \
+  case Value::NAME##Val:                                                       \
+    return static_cast<NAME *>(this)->removeFromParent();
+#include "llvm/IR/Value.def"
+  default:
+    break;
+  }
+  llvm_unreachable("not a global");
+}
+
+void GlobalValue::eraseFromParent() {
+  switch (getValueID()) {
+#define HANDLE_GLOBAL_VALUE(NAME)                                              \
+  case Value::NAME##Val:                                                       \
+    return static_cast<NAME *>(this)->eraseFromParent();
+#include "llvm/IR/Value.def"
+  default:
+    break;
+  }
+  llvm_unreachable("not a global");
+}
+
 unsigned GlobalValue::getAlignment() const {
   if (auto *GA = dyn_cast<GlobalAlias>(this)) {
     // In general we cannot compute this at the IR level, but we try.
@@ -93,12 +117,10 @@ void GlobalObject::setAlignment(unsigned Align) {
   assert(getAlignment() == Align && "Alignment representation error!");
 }
 
-void GlobalObject::copyAttributesFrom(const GlobalValue *Src) {
+void GlobalObject::copyAttributesFrom(const GlobalObject *Src) {
   GlobalValue::copyAttributesFrom(Src);
-  if (const auto *GV = dyn_cast<GlobalObject>(Src)) {
-    setAlignment(GV->getAlignment());
-    setSection(GV->getSection());
-  }
+  setAlignment(Src->getAlignment());
+  setSection(Src->getSection());
 }
 
 std::string GlobalValue::getGlobalIdentifier(StringRef Name,
@@ -333,13 +355,11 @@ void GlobalVariable::setInitializer(Constant *InitVal) {
 
 /// Copy all additional attributes (those not needed to create a GlobalVariable)
 /// from the GlobalVariable Src to this one.
-void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
+void GlobalVariable::copyAttributesFrom(const GlobalVariable *Src) {
   GlobalObject::copyAttributesFrom(Src);
-  if (const GlobalVariable *SrcVar = dyn_cast<GlobalVariable>(Src)) {
-    setThreadLocalMode(SrcVar->getThreadLocalMode());
-    setExternallyInitialized(SrcVar->isExternallyInitialized());
-    setAttributes(SrcVar->getAttributes());
-  }
+  setThreadLocalMode(Src->getThreadLocalMode());
+  setExternallyInitialized(Src->isExternallyInitialized());
+  setAttributes(Src->getAttributes());
 }
 
 void GlobalVariable::dropAllReferences() {