Make DataLayout Non-Optional in the Module

Summary:
DataLayout keeps the string used for its creation.

As a side effect it is no longer needed in the Module.
This is "almost" NFC, the string is no longer
canonicalized, you can't rely on two "equals" DataLayout
having the same string returned by getStringRepresentation().

Get rid of DataLayoutPass: the DataLayout is in the Module

The DataLayout is "per-module", let's enforce this by not
duplicating it more than necessary.
One more step toward non-optionality of the DataLayout in the
module.

Make DataLayout Non-Optional in the Module

Module->getDataLayout() will never returns nullptr anymore.

Reviewers: echristo

Subscribers: resistor, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D7992

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231270

1 files changed, 6 insertions, 12 deletions

diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index e09f02e7797..7f0fdb32f7b 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -672,17 +672,12 @@ bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
         getComdatLeader(SrcM, ComdatName, SrcGV))
       return true;
 
-    const DataLayout *DstDL = DstM->getDataLayout();
-    const DataLayout *SrcDL = SrcM->getDataLayout();
-    if (!DstDL || !SrcDL) {
-      return emitError(
-          "Linking COMDATs named '" + ComdatName +
-          "': can't do size dependent selection without DataLayout!");
-    }
+    const DataLayout &DstDL = DstM->getDataLayout();
+    const DataLayout &SrcDL = SrcM->getDataLayout();
     uint64_t DstSize =
-        DstDL->getTypeAllocSize(DstGV->getType()->getPointerElementType());
+        DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType());
     uint64_t SrcSize =
-        SrcDL->getTypeAllocSize(SrcGV->getType()->getPointerElementType());
+        SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType());
     if (Result == Comdat::SelectionKind::ExactMatch) {
       if (SrcGV->getInitializer() != DstGV->getInitializer())
         return emitError("Linking COMDATs named '" + ComdatName +
@@ -1482,11 +1477,10 @@ bool ModuleLinker::run() {
 
   // Inherit the target data from the source module if the destination module
   // doesn't have one already.
-  if (!DstM->getDataLayout() && SrcM->getDataLayout())
+  if (DstM->getDataLayout().isDefault())
     DstM->setDataLayout(SrcM->getDataLayout());
 
-  if (SrcM->getDataLayout() && DstM->getDataLayout() &&
-      *SrcM->getDataLayout() != *DstM->getDataLayout()) {
+  if (SrcM->getDataLayout() != DstM->getDataLayout()) {
     emitWarning("Linking two modules of different data layouts: '" +
                 SrcM->getModuleIdentifier() + "' is '" +
                 SrcM->getDataLayoutStr() + "' whereas '" +