Add constant blinding/pooling option for X8632 code translation

src/IceELFObjectWriter.cpp

Index: src/IceELFObjectWriter.cpp
diff --git a/src/IceELFObjectWriter.cpp b/src/IceELFObjectWriter.cpp
index 9c75482def48ede32edf4d4d097cd5b04e14e768..25138367e32c3ca98e240c68605e6beaca415cfe 100644
--- a/src/IceELFObjectWriter.cpp
+++ b/src/IceELFObjectWriter.cpp
@@ -383,8 +383,9 @@ void ELFObjectWriter::writeDataOfType(SectionType ST,
       for (VariableDeclaration::Initializer *Init : Var->getInitializers()) {
         switch (Init->getKind()) {
         case VariableDeclaration::Initializer::DataInitializerKind: {
-          const auto Data = llvm::cast<VariableDeclaration::DataInitializer>(
-                                Init)->getContents();
+          const auto Data =
+              llvm::cast<VariableDeclaration::DataInitializer>(Init)
+                  ->getContents();
           Section->appendData(Str, llvm::StringRef(Data.data(), Data.size()));
           break;
         }
@@ -504,6 +505,12 @@ template <typename ConstType> void ELFObjectWriter::writeConstantPool(Type Ty) {
   // Write the data.
   for (Constant *C : Pool) {
     auto Const = llvm::cast<ConstType>(C);
+    // When constant pooling turned on, only emit labels for eligible constants

[Jim Stichnoth, 2015/06/12 23:48:17]

end sentence with period

[qining, 2015/06/17 04:28:53]

Done.

+    // If C is i32 constant and not large enough, we should ignore it here.
+    if (llvm::isa<ConstantInteger32>(C) &&

[Jim Stichnoth, 2015/06/12 23:48:17]

Normally this kind of type checking would be done like this:

if (auto *CI32 = llvm::dyn_cast<ConstantInteger32>(C)) {
  if (!CI32->shouldBeRandomizedOrPooled(&Ctx))
    continue;
}

Note the use of dyn_cast<> instead of dyn_cast_or_null<> since we know C will
not be null.  Also note that the dyn_cast<> pattern handles both the isa<> check
and the cast.

However, can't you avoid all the type checking and just do this?

  if (!Const->shouldBeRandomizedOrPooled(&Ctx))
    continue;

[qining, 2015/06/17 04:28:53]

I have moved shouldBeRandomizedOrPooled() to class Constant or even Operand. 

shouldBePooled flag is also added to the Constant class.

+        llvm::dyn_cast_or_null<ConstantInteger32>(C)
+                ->shouldBeRandomizedOrPooled(&Ctx) == false)

[Jim Stichnoth, 2015/06/12 23:48:17]

use "!x" instead of "x==false"

[qining, 2015/06/17 04:28:53]

Done.

+      continue;
     std::string SymBuffer;
     llvm::raw_string_ostream SymStrBuf(SymBuffer);
     Const->emitPoolLabel(SymStrBuf);
@@ -528,6 +535,8 @@ template void ELFObjectWriter::writeConstantPool<ConstantFloat>(Type Ty);
 
 template void ELFObjectWriter::writeConstantPool<ConstantDouble>(Type Ty);
 
+template void ELFObjectWriter::writeConstantPool<ConstantInteger32>(Type Ty);
+
 void ELFObjectWriter::writeAllRelocationSections() {
   writeRelocationSections(RelTextSections);
   writeRelocationSections(RelDataSections);