From be5af50e7d028849bf2fab5f4b0f2ad36ae56e11 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Fri, 16 Jul 2021 20:26:40 +0200
Subject: [BPF] Use elementtype attribute for preserve.array/struct.index
 intrinsics

Use the elementtype attribute introduced in D105407 for the
llvm.preserve.array/struct.index intrinsics. It carries the
element type of the GEP these intrinsics effectively encode.

This patch:

 * Adds a verifier check that the attribute is required.
 * Adds it in the IRBuilder methods for these intrinsics.
 * Autoupgrades old bitcode without the attribute.
 * Updates the lowering code to use the attribute rather than
   the pointer element type.
 * Updates lots of tests to specify the attribute.
 * Adds -force-opaque-pointers to the intrinsic-array.ll test
   to demonstrate they work now.

https://reviews.llvm.org/D106184
---
 llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

(limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp')

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 07db3c0..42e17f0 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -682,9 +682,10 @@ private:
     return getFnValueByID(ValNo, Ty);
   }
 
-  /// Upgrades old-style typeless byval or sret attributes by adding the
-  /// corresponding argument's pointee type.
-  void propagateByValSRetTypes(CallBase *CB, ArrayRef<Type *> ArgsTys);
+  /// Upgrades old-style typeless byval/sret/inalloca attributes by adding the
+  /// corresponding argument's pointee type. Also upgrades intrinsics that now
+  /// require an elementtype attribute.
+  void propagateAttributeTypes(CallBase *CB, ArrayRef<Type *> ArgsTys);
 
   /// Converts alignment exponent (i.e. power of two (or zero)) to the
   /// corresponding alignment to use. If alignment is too large, returns
@@ -3809,7 +3810,7 @@ Error BitcodeReader::typeCheckLoadStoreInst(Type *ValType, Type *PtrType) {
   return Error::success();
 }
 
-void BitcodeReader::propagateByValSRetTypes(CallBase *CB,
+void BitcodeReader::propagateAttributeTypes(CallBase *CB,
                                             ArrayRef<Type *> ArgsTys) {
   for (unsigned i = 0; i != CB->arg_size(); ++i) {
     for (Attribute::AttrKind Kind : {Attribute::ByVal, Attribute::StructRet,
@@ -3838,6 +3839,19 @@ void BitcodeReader::propagateByValSRetTypes(CallBase *CB,
       CB->addParamAttr(i, NewAttr);
     }
   }
+
+  switch (CB->getIntrinsicID()) {
+  case Intrinsic::preserve_array_access_index:
+  case Intrinsic::preserve_struct_access_index:
+    if (!CB->getAttributes().getParamElementType(0)) {
+      Type *ElTy = cast<PointerType>(ArgsTys[0])->getElementType();
+      Attribute NewAttr = Attribute::get(Context, Attribute::ElementType, ElTy);
+      CB->addParamAttr(0, NewAttr);
+    }
+    break;
+  default:
+    break;
+  }
 }
 
 /// Lazily parse the specified function body block.
@@ -4679,7 +4693,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
       cast<InvokeInst>(I)->setCallingConv(
           static_cast<CallingConv::ID>(CallingConv::MaxID & CCInfo));
       cast<InvokeInst>(I)->setAttributes(PAL);
-      propagateByValSRetTypes(cast<CallBase>(I), ArgsTys);
+      propagateAttributeTypes(cast<CallBase>(I), ArgsTys);
 
       break;
     }
@@ -5318,7 +5332,7 @@ Error BitcodeReader::parseFunctionBody(Function *F) {
         TCK = CallInst::TCK_NoTail;
       cast<CallInst>(I)->setTailCallKind(TCK);
       cast<CallInst>(I)->setAttributes(PAL);
-      propagateByValSRetTypes(cast<CallBase>(I), ArgsTys);
+      propagateAttributeTypes(cast<CallBase>(I), ArgsTys);
       if (FMF.any()) {
         if (!isa<FPMathOperator>(I))
           return error("Fast-math-flags specified for call without "
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