[IR][ARM] Add function pointer alignment to datalayout

Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.

Differential Revision: https://reviews.llvm.org/D57335

llvm-svn: 355522

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/lib/IR/DataLayout.cpp b/llvm/lib/IR/DataLayout.cpp
index 2644214a49c..943f5381c64 100644
--- a/llvm/lib/IR/DataLayout.cpp
+++ b/llvm/lib/IR/DataLayout.cpp
@@ -184,6 +184,8 @@ void DataLayout::reset(StringRef Desc) {
   AllocaAddrSpace = 0;
   StackNaturalAlign = 0;
   ProgramAddrSpace = 0;
+  FunctionPtrAlign = 0;
+  TheFunctionPtrAlignType = FunctionPtrAlignType::Independent;
   ManglingMode = MM_None;
   NonIntegralAddressSpaces.clear();
 
@@ -379,6 +381,22 @@ void DataLayout::parseSpecifier(StringRef Desc) {
       StackNaturalAlign = inBytes(getInt(Tok));
       break;
     }
+    case 'F': {
+      switch (Tok.front()) {
+      case 'i':
+        TheFunctionPtrAlignType = FunctionPtrAlignType::Independent;
+        break;
+      case 'n':
+        TheFunctionPtrAlignType = FunctionPtrAlignType::MultipleOfFunctionAlign;
+        break;
+      default:
+        report_fatal_error("Unknown function pointer alignment type in "
+                           "datalayout string");
+      }
+      Tok = Tok.substr(1);
+      FunctionPtrAlign = inBytes(getInt(Tok));
+      break;
+    }
     case 'P': { // Function address space.
       ProgramAddrSpace = getAddrSpace(Tok);
       break;
@@ -432,6 +450,8 @@ bool DataLayout::operator==(const DataLayout &Other) const {
              AllocaAddrSpace == Other.AllocaAddrSpace &&
              StackNaturalAlign == Other.StackNaturalAlign &&
              ProgramAddrSpace == Other.ProgramAddrSpace &&
+             FunctionPtrAlign == Other.FunctionPtrAlign &&
+             TheFunctionPtrAlignType == Other.TheFunctionPtrAlignType &&
              ManglingMode == Other.ManglingMode &&
              LegalIntWidths == Other.LegalIntWidths &&
              Alignments == Other.Alignments && Pointers == Other.Pointers;