commit a78e4baab1557beccdb7604175dcea97ef1afe06
author John Porto <jpp@chromium.org> Tue Mar 15 09:28:04 2016 -0700
committer John Porto <jpp@chromium.org> Tue Mar 15 09:28:04 2016 -0700
tree eef4a2556f69ef8b2c94f2ab0cc01ba5dd3840ac
parent 76719b4aab9bdc44a9d37004aba64471790ab574

Subzero. Allocate global initializers from a dedicated arena.

This allows Subzero to release the global initializers once they've been
lowered.

This CL also modifies the global initializer types to ensure they are
trivially destructible -- therefore not requiring destructors to run.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4360
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/1776473007 .

src/IceConverter.cpp

diff --git a/src/IceConverter.cpp b/src/IceConverter.cpp
index 2440353..7dc666f 100644
--- a/src/IceConverter.cpp
+++ b/src/IceConverter.cpp
@@ -659,13 +659,13 @@
   operator=(const LLVM2ICEGlobalsConverter &) = delete;
 
 public:
-  explicit LLVM2ICEGlobalsConverter(Ice::Converter &Converter)
-      : LLVM2ICEConverter(Converter) {}
+  explicit LLVM2ICEGlobalsConverter(Ice::Converter &Converter,
+                                    Ice::VariableDeclarationList *G)
+      : LLVM2ICEConverter(Converter), GlobalPool(G) {}
 
   /// Converts global variables, and their initializers into ICE global variable
   /// declarations, for module Mod. Returns the set of converted declarations.
-  std::unique_ptr<Ice::VariableDeclarationList>
-  convertGlobalsToIce(Module *Mod);
+  void convertGlobalsToIce(Module *Mod);
 
 private:
   // Adds the Initializer to the list of initializers for the Global variable
@@ -697,12 +697,11 @@
     report_fatal_error(StrBuf.str());
     return 0;
   }
+
+  Ice::VariableDeclarationList *GlobalPool;
 };
 
-std::unique_ptr<Ice::VariableDeclarationList>
-LLVM2ICEGlobalsConverter::convertGlobalsToIce(Module *Mod) {
-  std::unique_ptr<Ice::VariableDeclarationList> VariableDeclarations(
-      new Ice::VariableDeclarationList);
+void LLVM2ICEGlobalsConverter::convertGlobalsToIce(Module *Mod) {
   for (Module::const_global_iterator I = Mod->global_begin(),
                                      E = Mod->global_end();
        I != E; ++I) {
@@ -711,7 +710,7 @@
 
     Ice::GlobalDeclaration *Var = getConverter().getGlobalDeclaration(GV);
     auto *VarDecl = cast<Ice::VariableDeclaration>(Var);
-    VariableDeclarations->push_back(VarDecl);
+    GlobalPool->push_back(VarDecl);
 
     if (!GV->hasInternalLinkage() && GV->hasInitializer()) {
       std::string Buffer;
@@ -744,7 +743,6 @@
       addGlobalInitializer(*VarDecl, Initializer);
     }
   }
-  return VariableDeclarations;
 }
 
 void LLVM2ICEGlobalsConverter::addGlobalInitializer(
@@ -757,7 +755,7 @@
     assert(!HasOffset && isa<IntegerType>(CDA->getElementType()) &&
            (cast<IntegerType>(CDA->getElementType())->getBitWidth() == 8));
     Global.addInitializer(Ice::VariableDeclaration::DataInitializer::create(
-        CDA->getRawDataValues().data(), CDA->getNumElements()));
+        GlobalPool, CDA->getRawDataValues().data(), CDA->getNumElements()));
     return;
   }
 
@@ -766,7 +764,7 @@
       assert(!HasOffset && isa<IntegerType>(AT->getElementType()) &&
              (cast<IntegerType>(AT->getElementType())->getBitWidth() == 8));
       Global.addInitializer(Ice::VariableDeclaration::ZeroInitializer::create(
-          AT->getNumElements()));
+          GlobalPool, AT->getNumElements()));
     } else {
       llvm_unreachable("Unhandled constant aggregate zero type");
     }
@@ -788,7 +786,7 @@
       const Ice::GlobalDeclaration *Addr =
           getConverter().getGlobalDeclaration(GV);
       Global.addInitializer(Ice::VariableDeclaration::RelocInitializer::create(
-          Addr, {Ice::RelocOffset::create(Ctx, Offset)}));
+          GlobalPool, Addr, {Ice::RelocOffset::create(Ctx, Offset)}));
       return;
     }
     default:
@@ -890,8 +888,8 @@
        I != E; ++I) {
     const GlobalVariable *GV = I;
     constexpr bool NoSuppressMangling = false;
-    auto *Var =
-        VariableDeclaration::create(Ctx, NoSuppressMangling, GV->getLinkage());
+    auto *Var = VariableDeclaration::create(
+        GlobalDeclarationsPool.get(), NoSuppressMangling, GV->getLinkage());
     Var->setAlignment(GV->getAlignment());
     Var->setIsConstant(GV->isConstant());
     Var->setName(GV->getName());
@@ -909,7 +907,9 @@
 }
 
 void Converter::convertGlobals(Module *Mod) {
-  lowerGlobals(LLVM2ICEGlobalsConverter(*this).convertGlobalsToIce(Mod));
+  LLVM2ICEGlobalsConverter(*this, GlobalDeclarationsPool.get())
+      .convertGlobalsToIce(Mod);
+  lowerGlobals(std::move(GlobalDeclarationsPool));
 }
 
 void Converter::convertFunctions() {