OpaquePtr: Reject 'ptr*' again when parsing textual IR

[dexonsmith]

Summary

Bring back the testcase dropped in
1e6303e60ca5af4fbe7ca728572fd65666a98271 and get it passing by checking
explicitly for ptr* in LLParser. Added Type::isOpaquePointerTy() for
convenience.

[nikic]

LGTM -- looks like we had a bit of race condition, I just committed ad4bb8280952c2cacf497e30560ee94c119b36e0 in preparation for doing the same change...

[aeubanks]

lgtm but with a comment on the newly added method

llvm/include/llvm/IR/Type.h

231 ↗

(On Diff #354567)

I have a mild preference to not add these one off sort of methods when we already have lots of code that does isa<PointerType> && cast<PointerType>(Ty)->isOpaque()

[dexonsmith]

Thanks for both reviews! Landed in 4506f614cb6983a16d117cf77a968608e66d7a5c.

In D104938#2841449, @nikic wrote:

LGTM -- looks like we had a bit of race condition, I just committed ad4bb8280952c2cacf497e30560ee94c119b36e0 in preparation for doing the same change...

Yeah, sorry about that / thanks; after I left the other review I realized it was easy enough for me to pitch in here :).

llvm/include/llvm/IR/Type.h

231 ↗

(On Diff #354567)

Agreed it shouldn't be a one off, was surprised it hadn't been added yet though... I'll see if I can find time to clean up the existing boilerplate instances to use this helper (note that @nikic already added it).

[dexonsmith]

llvm/include/llvm/IR/Type.h

231 ↗

(On Diff #354567)

Actually, git-grep can't come up with any examples of the more verbose pattern anymore... looks like @nikic cleaned them all up.

[nikic]

llvm/lib/AsmParser/LLParser.cpp

2601

This breaks pointer to pointer types in -force-opaque-pointers mode:

define void @test(i32** %x) {}

Results in:

build/bin/opt: test303.ll:1:23: error: ptr* is invalid - use ptr instead

[dexonsmith]

llvm/lib/AsmParser/LLParser.cpp

2601

Looking.

[dexonsmith]

llvm/lib/AsmParser/LLParser.cpp

2601

Fixed by https://reviews.llvm.org/D105146.

llvm/lib/AsmParser/LLParser.cpp

default:
       return false;
 
     // Type ::= Type '*'
     case lltok::star:
       if (Result->isLabelTy())
         return tokError("basic block pointers are invalid");
       if (Result->isVoidTy())
         return tokError("pointers to void are invalid - use i8* instead");
+      if (Result->isOpaquePointerTy())
+        return tokError("ptr* is invalid - use ptr instead");
       if (!PointerType::isValidElementType(Result))
         return tokError("pointer to this type is invalid");
       Result = PointerType::getUnqual(Result);
       Lex.Lex();
       break;
 
     // Type ::= Type 'addrspace' '(' uint32 ')' '*'
     case lltok::kw_addrspace: {

llvm/test/Assembler/invalid-opaque-ptr-addrspace.ll

+; RUN: not llvm-as < %s -disable-output 2>&1 | FileCheck %s
+
+; CHECK: ptr* is invalid - use ptr instead
+define void @f(ptr addrspace(3) %a) {
+    %b = bitcast ptr addrspace(3) %a to ptr addrspace(3)*
+    ret void
+}

llvm/test/Assembler/invalid-opaque-ptr.ll

+; RUN: not llvm-as < %s -disable-output 2>&1 | FileCheck %s
+
+; CHECK: ptr* is invalid - use ptr instead
+define void @f(ptr %a) {
+    %b = bitcast ptr %a to ptr*
+    ret void
+}