Add IR support, ELF section and user documentation for partitioning feature.

The partitioning feature was proposed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html

This is mostly just documentation. The feature itself will be contributed
in subsequent patches.

Differential Revision: https://reviews.llvm.org/D60242

llvm-svn: 361923

1 files changed, 23 insertions, 0 deletions

diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index b3fdcc6a5fc..e2bfc0420bc 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -67,6 +67,7 @@ void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
   setUnnamedAddr(Src->getUnnamedAddr());
   setDLLStorageClass(Src->getDLLStorageClass());
   setDSOLocal(Src->isDSOLocal());
+  setPartition(Src->getPartition());
 }
 
 void GlobalValue::removeFromParent() {
@@ -180,6 +181,28 @@ const Comdat *GlobalValue::getComdat() const {
   return cast<GlobalObject>(this)->getComdat();
 }
 
+StringRef GlobalValue::getPartition() const {
+  if (!hasPartition())
+    return "";
+  return getContext().pImpl->GlobalValuePartitions[this];
+}
+
+void GlobalValue::setPartition(StringRef S) {
+  // Do nothing if we're clearing the partition and it is already empty.
+  if (!hasPartition() && S.empty())
+    return;
+
+  // Get or create a stable partition name string and put it in the table in the
+  // context.
+  if (!S.empty())
+    S = getContext().pImpl->Saver.save(S);
+  getContext().pImpl->GlobalValuePartitions[this] = S;
+
+  // Update the HasPartition field. Setting the partition to the empty string
+  // means this global no longer has a partition.
+  HasPartition = !S.empty();
+}
+
 StringRef GlobalObject::getSectionImpl() const {
   assert(hasSection());
   return getContext().pImpl->GlobalObjectSections[this];