[PATCH] D82679: OpaquePtr: Don't check pointee type for byval/preallocated

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: jdoerfert, rnk, bkramer, craig.topper, t.p.northover.
Herald added subscribers: hiraditya, wdng.
Herald added a project: LLVM.

Since none of these users really care about the actual type, hide the
type under a new size-getting attribute to go along with
hasPassPointeeByValueAttr. This will work better for the future byref
attribute, which may end up only tracking the byte size and not the IR
type.

      

We currently have 3 parameter attributes that should carry the type
(technically inalloca does not yet). The APIs are somewhat awkward
since preallocated/inalloca piggyback on byval in some places, but in
others are treated as distinct attributes. Since these are all
mutually exclusive, we should probably just merge all the attribute
infrastructure treating these as totally distinct attributes.


https://reviews.llvm.org/D82679

Files:
  llvm/include/llvm/IR/Argument.h
  llvm/lib/IR/Function.cpp
  llvm/lib/IR/Mangler.cpp


Index: llvm/lib/IR/Mangler.cpp
===================================================================
--- llvm/lib/IR/Mangler.cpp
+++ llvm/lib/IR/Mangler.cpp
@@ -94,15 +94,18 @@
                                const DataLayout &DL) {
   // Calculate arguments size total.
   unsigned ArgWords = 0;
+
+  const unsigned PtrSize = DL.getPointerSize();
+
   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
        AI != AE; ++AI) {
-    Type *Ty = AI->getType();
     // 'Dereference' type in case of byval or inalloca parameter attribute.
-    if (AI->hasPassPointeeByValueAttr())
-      Ty = cast<PointerType>(Ty)->getElementType();
+    uint64_t AllocSize = AI->hasPassPointeeByValueAttr() ?
+      AI->getPassPointeeByValueAllocSize(DL) :
+      DL.getTypeAllocSize(AI->getType());
+
     // Size should be aligned to pointer size.
-    unsigned PtrSize = DL.getPointerSize();
-    ArgWords += alignTo(DL.getTypeAllocSize(Ty), PtrSize);
+    ArgWords += alignTo(AllocSize, PtrSize);
   }
 
   OS << '@' << ArgWords;
Index: llvm/lib/IR/Function.cpp
===================================================================
--- llvm/lib/IR/Function.cpp
+++ llvm/lib/IR/Function.cpp
@@ -128,6 +128,27 @@
          Attrs.hasParamAttribute(getArgNo(), Attribute::Preallocated);
 }
 
+uint64_t Argument::getPassPointeeByValueAllocSize(const DataLayout &DL) const {
+  AttributeSet ParamAttrs
+    = getParent()->getAttributes().getParamAttributes(getArgNo());
+
+  // FIXME: All the type carrying attributes are mutually exclusive, so there
+  // should be a single query to get the stored type that handles any of them.
+  if (Type *ByValTy = ParamAttrs.getByValType())
+    return DL.getTypeAllocSize(ByValTy);
+  if (Type *PreAllocTy = ParamAttrs.getPreallocatedType())
+    return DL.getTypeAllocSize(PreAllocTy);
+
+  // FIXME: inalloca always depends on pointee element type. It's also possible
+  // for byval to miss it.
+  if (ParamAttrs.hasAttribute(Attribute::InAlloca) ||
+      ParamAttrs.hasAttribute(Attribute::ByVal) ||
+      ParamAttrs.hasAttribute(Attribute::Preallocated))
+    return DL.getTypeAllocSize(cast<PointerType>(getType())->getElementType());
+
+  return 0;
+}
+
 unsigned Argument::getParamAlignment() const {
   assert(getType()->isPointerTy() && "Only pointers have alignments");
   return getParent()->getParamAlignment(getArgNo());
Index: llvm/include/llvm/IR/Argument.h
===================================================================
--- llvm/include/llvm/IR/Argument.h
+++ llvm/include/llvm/IR/Argument.h
@@ -75,6 +75,10 @@
   /// attribute. These attributes represent arguments being passed by value.
   bool hasPassPointeeByValueAttr() const;
 
+  /// If this argument satisfies has hasPassPointeeByValueAttr, return the
+  /// in-memory ABI size. Otherwise, return 0.
+  uint64_t getPassPointeeByValueAllocSize(const DataLayout &DL) const;
+
   /// If this is a byval or inalloca argument, return its alignment.
   /// FIXME: Remove this function once transition to Align is over.
   /// Use getParamAlign() instead.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D82679.273814.patch
Type: text/x-patch
Size: 3073 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200626/1e7e47ef/attachment.bin>