r346548 - Use the correct address space when bitcasting func pointer to int pointer

Dylan McKay via cfe-commits cfe-commits at lists.llvm.org
Fri Nov 9 11:42:05 PST 2018

Author: dylanmckay
Date: Fri Nov  9 11:42:05 2018
New Revision: 346548

URL: http://llvm.org/viewvc/llvm-project?rev=346548&view=rev
Use the correct address space when bitcasting func pointer to int pointer

When we cast a function pointer to an int pointer, at some pointer later
it gets bitcasted back to a function and called.

In backends that have a nonzero program memory address space specified
in the data layout, the old code would lose the address space data. When
LLVM later attempted to generate the bitcast from i8* to i8(..)*
addrspace(1), it would fail because the pointers are not in the same
address space.

With this patch, the address space of the function will carry on to the
address space of the i8* pointer. This is because all function pointers
in Harvard architectures need to be assigned to the correct address

This has no effect to any in-tree backends except AVR.


Modified: cfe/trunk/lib/CodeGen/CGException.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGException.cpp?rev=346548&r1=346547&r2=346548&view=diff
--- cfe/trunk/lib/CodeGen/CGException.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGException.cpp Fri Nov  9 11:42:05 2018
@@ -250,7 +250,11 @@ static llvm::Constant *getPersonalityFn(
 static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
                                         const EHPersonality &Personality) {
   llvm::Constant *Fn = getPersonalityFn(CGM, Personality);
-  return llvm::ConstantExpr::getBitCast(Fn, CGM.Int8PtrTy);
+  llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
+      llvm::Type::getInt8Ty(CGM.getLLVMContext()),
+      CGM.getDataLayout().getProgramAddressSpace());
+  return llvm::ConstantExpr::getBitCast(Fn, Int8PtrTy);
 /// Check whether a landingpad instruction only uses C++ features.

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