[IR] Introduce a non-integral pointer type

Summary:
This change adds a `ni` specifier in the `datalayout` string to denote
pointers in some given address spaces as "non-integral", and adds some
typing rules around these special pointers.

Reviewers: majnemer, chandlerc, atrick, dberlin, eli.friedman, tstellarAMD, arsenm

Subscribers: arsenm, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D22488

llvm-svn: 277085

2 files changed, 24 insertions, 0 deletions

diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp
index 20a15fb8831..d7ed73015ee 100644
--- a/llvm/lib/IR/DataLayout.cpp
+++ b/llvm/lib/IR/DataLayout.cpp
@@ -182,6 +182,7 @@ void DataLayout::reset(StringRef Desc) {
   BigEndian = false;
   StackNaturalAlign = 0;
   ManglingMode = MM_None;
+  NonIntegralAddressSpaces.clear();
 
   // Default alignments
   for (const LayoutAlignElem &E : DefaultAlignments) {
@@ -234,6 +235,19 @@ void DataLayout::parseSpecifier(StringRef Desc) {
     StringRef &Tok  = Split.first;  // Current token.
     StringRef &Rest = Split.second; // The rest of the string.
 
+    if (Tok == "ni") {
+      do {
+        Split = split(Rest, ':');
+        Rest = Split.second;
+        unsigned AS = getInt(Split.first);
+        if (AS == 0)
+          report_fatal_error("Address space 0 can never be non-integral");
+        NonIntegralAddressSpaces.push_back(AS);
+      } while (!Rest.empty());
+
+      continue;
+    }
+
     char Specifier = Tok.front();
     Tok = Tok.substr(1);
 
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 659a22428e2..7815207fd9f 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -2409,6 +2409,11 @@ void Verifier::visitPtrToIntInst(PtrToIntInst &I) {
 
   Assert(SrcTy->getScalarType()->isPointerTy(),
          "PtrToInt source must be pointer", &I);
+
+  if (auto *PTy = dyn_cast<PointerType>(SrcTy->getScalarType()))
+    Assert(!M->getDataLayout().isNonIntegralPointerType(PTy),
+           "ptrtoint not supported for non-integral pointers");
+
   Assert(DestTy->getScalarType()->isIntegerTy(),
          "PtrToInt result must be integral", &I);
   Assert(SrcTy->isVectorTy() == DestTy->isVectorTy(), "PtrToInt type mismatch",
@@ -2433,6 +2438,11 @@ void Verifier::visitIntToPtrInst(IntToPtrInst &I) {
          "IntToPtr source must be an integral", &I);
   Assert(DestTy->getScalarType()->isPointerTy(),
          "IntToPtr result must be a pointer", &I);
+
+  if (auto *PTy = dyn_cast<PointerType>(DestTy->getScalarType()))
+    Assert(!M->getDataLayout().isNonIntegralPointerType(PTy),
+           "inttoptr not supported for non-integral pointers");
+
   Assert(SrcTy->isVectorTy() == DestTy->isVectorTy(), "IntToPtr type mismatch",
          &I);
   if (SrcTy->isVectorTy()) {