[llvm] 8c7349b - [OpaquePtr] Support opaque pointers in intrinsic type check

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2021-07-01T18:26:41+02:00
New Revision: 8c7349b3f43267036f6c133d3502def86307528a

URL: https://github.com/llvm/llvm-project/commit/8c7349b3f43267036f6c133d3502def86307528a
DIFF: https://github.com/llvm/llvm-project/commit/8c7349b3f43267036f6c133d3502def86307528a.diff

LOG: [OpaquePtr] Support opaque pointers in intrinsic type check

This adds support for opaque pointers in intrinsic type checks
of IIT kind Pointer and PtrToElt.

This is less straight-forward than it might initially seem, because
we should only accept opaque pointers here in --force-opaque-pointers
mode. Otherwise, there would be more than one valid type signature
for a given intrinsic name.

Differential Revision: https://reviews.llvm.org/D105155

Added: 
    llvm/test/Assembler/remangle-intrinsic-opaque-ptr.ll

Modified: 
    llvm/include/llvm/IR/LLVMContext.h
    llvm/lib/IR/Function.cpp
    llvm/lib/IR/LLVMContext.cpp
    llvm/test/Other/force-opaque-ptrs.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/IR/LLVMContext.h b/llvm/include/llvm/IR/LLVMContext.h
index 3bd889485dd1d..50671db30eeb3 100644
--- a/llvm/include/llvm/IR/LLVMContext.h
+++ b/llvm/include/llvm/IR/LLVMContext.h
@@ -305,6 +305,9 @@ class LLVMContext {
   /// LLVMContext is used by compilation.
   void setOptPassGate(OptPassGate&);
 
+  /// Whether typed pointers are supported. If false, all pointers are opaque.
+  bool supportsTypedPointers() const;
+
 private:
   // Module needs access to the add/removeModule methods.
   friend class Module;

diff  --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index 07c603fd98a6a..8f096f0a69eb4 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -1404,9 +1404,21 @@ static bool matchIntrinsicType(
     }
     case IITDescriptor::Pointer: {
       PointerType *PT = dyn_cast<PointerType>(Ty);
-      return !PT || PT->getAddressSpace() != D.Pointer_AddressSpace ||
-             matchIntrinsicType(PT->getElementType(), Infos, ArgTys,
-                                DeferredChecks, IsDeferredCheck);
+      if (!PT || PT->getAddressSpace() != D.Pointer_AddressSpace)
+        return true;
+      if (!PT->isOpaque())
+        return matchIntrinsicType(PT->getElementType(), Infos, ArgTys,
+                                  DeferredChecks, IsDeferredCheck);
+      // If typed pointers are supported, do not allow using opaque pointer in
+      // place of fixed pointer type. This would make the intrinsic signature
+      // non-unique.
+      if (Ty->getContext().supportsTypedPointers())
+        return true;
+      // Consume IIT descriptors relating to the pointer element type.
+      while (Infos.front().Kind == IITDescriptor::Pointer)
+        Infos = Infos.slice(1);
+      Infos = Infos.slice(1);
+      return false;
     }
 
     case IITDescriptor::Struct: {
@@ -1517,8 +1529,13 @@ static bool matchIntrinsicType(
         dyn_cast<VectorType> (ArgTys[D.getArgumentNumber()]);
       PointerType *ThisArgType = dyn_cast<PointerType>(Ty);
 
-      return (!ThisArgType || !ReferenceType ||
-              ThisArgType->getElementType() != ReferenceType->getElementType());
+      if (!ThisArgType || !ReferenceType)
+        return true;
+      if (!ThisArgType->isOpaque())
+        return ThisArgType->getElementType() != ReferenceType->getElementType();
+      // If typed pointers are supported, do not allow opaque pointer to ensure
+      // uniqueness.
+      return Ty->getContext().supportsTypedPointers();
     }
     case IITDescriptor::VecOfAnyPtrsToElt: {
       unsigned RefArgNumber = D.getRefArgNumber();

diff  --git a/llvm/lib/IR/LLVMContext.cpp b/llvm/lib/IR/LLVMContext.cpp
index 79002fb1b1bc7..234806b5dce03 100644
--- a/llvm/lib/IR/LLVMContext.cpp
+++ b/llvm/lib/IR/LLVMContext.cpp
@@ -347,3 +347,7 @@ const DiagnosticHandler *LLVMContext::getDiagHandlerPtr() const {
 std::unique_ptr<DiagnosticHandler> LLVMContext::getDiagnosticHandler() {
   return std::move(pImpl->DiagHandler);
 }
+
+bool LLVMContext::supportsTypedPointers() const {
+  return !pImpl->ForceOpaquePointers;
+}

diff  --git a/llvm/test/Assembler/remangle-intrinsic-opaque-ptr.ll b/llvm/test/Assembler/remangle-intrinsic-opaque-ptr.ll
new file mode 100644
index 0000000000000..6f7930ce4e162
--- /dev/null
+++ b/llvm/test/Assembler/remangle-intrinsic-opaque-ptr.ll
@@ -0,0 +1,20 @@
+; RUN: not llvm-as < %s -disable-output 2>&1 | FileCheck %s --check-prefix=TYPED
+; RUN: llvm-as --force-opaque-pointers < %s | llvm-dis --force-opaque-pointers | FileCheck %s --check-prefix=OPAQUE
+
+; An opaque pointer type should not be accepted for an intrinsic that
+; specifies a fixed pointer type, outside of --force-opaque-pointers mode.
+
+define void @test() {
+; TYPED: Intrinsic has incorrect return type!
+; OPAQUE: call ptr @llvm.stacksave()
+  call ptr @llvm.stacksave()
+
+; TYPED: Intrinsic has incorrect argument type!
+; OPAQUE: call <2 x i64> @llvm.masked.expandload.v2i64(ptr null, <2 x i1> zeroinitializer, <2 x i64> zeroinitializer)
+  call <2 x i64> @llvm.masked.expandload.v2i64(ptr null, <2 x i1> zeroinitializer, <2 x i64> zeroinitializer)
+
+  ret void
+}
+
+declare ptr @llvm.stacksave()
+declare <2 x i64> @llvm.masked.expandload.v2i64(ptr, <2 x i1>, <2 x i64>)

diff  --git a/llvm/test/Other/force-opaque-ptrs.ll b/llvm/test/Other/force-opaque-ptrs.ll
index 1a0738dfcd637..ee7c752de4113 100644
--- a/llvm/test/Other/force-opaque-ptrs.ll
+++ b/llvm/test/Other/force-opaque-ptrs.ll
@@ -48,3 +48,22 @@ define void @f3(i32 addrspace(1)* addrspace(2)* %p) {
 ;
   unreachable
 }
+
+define void @remangle_intrinsic() {
+; CHECK-LABEL: define {{[^@]+}}@remangle_intrinsic() {
+; CHECK-NEXT:    [[A:%.*]] = alloca ptr, align 8
+; CHECK-NEXT:    [[TMP1:%.*]] = call ptr @llvm.stacksave()
+; CHECK-NEXT:    call void @llvm.stackprotector(ptr null, ptr [[A]])
+; CHECK-NEXT:    [[TMP2:%.*]] = call <2 x i64> @llvm.masked.expandload.v2i64(ptr null, <2 x i1> zeroinitializer, <2 x i64> zeroinitializer)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca i8*
+  call i8* @llvm.stacksave()
+  call void @llvm.stackprotector(i8* null, i8** %a)
+  call <2 x i64> @llvm.masked.expandload.v2i64(i64* null, <2 x i1> zeroinitializer, <2 x i64> zeroinitializer)
+  ret void
+}
+
+declare i8* @llvm.stacksave()
+declare void @llvm.stackprotector(i8*, i8**)
+declare <2 x i64> @llvm.masked.expandload.v2i64(i64*, <2 x i1>, <2 x i64>)