[PATCH] D89909: [SYCL] Implement SYCL address space attributes handling

[Alexey Bader via Phabricator via cfe-commits]

bader created this revision.
bader added reviewers: Anastasia, keryell, Naghasan, asavonic, Fznamznon.
Herald added subscribers: llvm-commits, cfe-commits, dexonsmith, kerbowa, ebevhan, hiraditya, yaxunl, nhaehnle, jvesely, jholewinski.
Herald added projects: clang, LLVM.
bader requested review of this revision.

Default address space (applies when no explicit address space was
specified) maps to generic (4) address space.

Added SYCLDevice environment to triple.

Static variables without address space now reside in global address
space, unless they have an explicit address space qualifier in source
code.

Although OpenCL specification explicitly states that a string literal
should reside in constant address space, it does not work for SYCL
with "generic by default" address space rules.

For example:

  const char *getLiteral() {
    return "A";
  }
  
  void func(bool AorB) {
    char B[] = {'B', '\0'};
    const char* C = AorB ? A : B;
  }

If `A' reside in constant address space, it cannot be returned from a
function `getLiteral', because it returns a generic const char*.

When default address space values in C++ are CodeGen'ed into different
address spaces in LLVM IR, we must ensure that an addrspacecast is
emitted before a bitcast.

Pointers with the same address space in AST may end up in different
address spaces in IR. We cannot CodeGen a conditional
operator (ternary 'if') whose operands have different address spaces,
so we have to addrspacecast them to generic.

When a static variable is lowered from AST to LLVM IR, it can change an
address space depending on its storage class. For example, a static
variable declared in function scope may be assigned to global address
space if language rules allow. When this happens, original address space
of a variable (retuned by D.getType()) is no longer can be used as
target address space. Correct address space for a global can be obtained
from CodeGenModule::GetGlobalVarAddressSpace function, but in this case
we just copy it from the existing global (OldGV).

Pointers with the same address space in AST may end up in different
address spaces in IR. We cannot CodeGen a binary compare
operator (<, >, ==, etc.) whose operands have different address spaces,
so we have to addrspacecast them to generic.

Emit address space cast if return type and return value have different
address spaces.

Invalid bitcast with different address spaces was emitted as arument of
llvm.invariant.start intrinsic for work group scope constants.
This problem caused assertion fail.

Make sure that all operands of phi instruction that is generated while
lowering conditional operator have the same type. This fixes compiler
assertion.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D89909

Files:
  clang/include/clang/AST/Type.h
  clang/include/clang/Basic/AddressSpaces.h
  clang/include/clang/Sema/ParsedAttr.h
  clang/lib/AST/ASTContext.cpp
  clang/lib/AST/ItaniumMangle.cpp
  clang/lib/AST/TypePrinter.cpp
  clang/lib/Basic/Targets.cpp
  clang/lib/Basic/Targets/AMDGPU.cpp
  clang/lib/Basic/Targets/NVPTX.h
  clang/lib/Basic/Targets/SPIR.h
  clang/lib/Basic/Targets/TCE.h
  clang/lib/Basic/Targets/X86.h
  clang/lib/CodeGen/CGCall.cpp
  clang/lib/CodeGen/CGClass.cpp
  clang/lib/CodeGen/CGDecl.cpp
  clang/lib/CodeGen/CGDeclCXX.cpp
  clang/lib/CodeGen/CGExpr.cpp
  clang/lib/CodeGen/CGExprScalar.cpp
  clang/lib/CodeGen/CGStmt.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Sema/SemaType.cpp
  clang/test/CodeGenSYCL/address-space-cond-op.cpp
  clang/test/CodeGenSYCL/address-space-of-returns.cpp
  clang/test/CodeGenSYCL/address-space-parameter-conversions.cpp
  clang/test/CodeGenSYCL/address-spaces.cpp
  clang/test/SemaSYCL/address-space-parameter-conversions.cpp
  clang/test/SemaTemplate/address_space-dependent.cpp
  llvm/include/llvm/ADT/Triple.h
  llvm/lib/Support/Triple.cpp

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