[PATCH] D118402: [C2x][ObjC] Do not crash when trying to encode a _BitInt type

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman created this revision.
aaron.ballman added reviewers: rjmccall, ahatanak, erichkeane.
aaron.ballman requested review of this revision.
Herald added a project: clang.

Using a `_BitInt` (or `_ExtInt`) type as a block parameter or block return type hits an "unreachable" when trying to determine the encoding for the block. Instead of crashing, this patch handles it like some of the other types for which we don't yet have an encoding. The test case verifies we no longer crash, but does not verify that we provide any particular encoding (it can be updated once someone more familiar with ObjC steps in to define the encoding).

Fixes PR50503.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118402

Files:
  clang/lib/AST/ASTContext.cpp
  clang/test/CodeGenObjC/encode-test-bitint.m


Index: clang/test/CodeGenObjC/encode-test-bitint.m
===================================================================
--- /dev/null
+++ clang/test/CodeGenObjC/encode-test-bitint.m
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple i686-apple-darwin9 -fobjc-runtime=macosx-fragile-10.5 -fblocks -emit-llvm -o /dev/null %s
+
+// Using a _BitInt as a block parameter or return type previously would crash
+// when getting the ObjC encoding for the type. Verify that we no longer crash,
+// but do not verify any particular encoding (one has not yet been determined).
+void foo1(void)
+{
+    __auto_type blk = ^int(unsigned _BitInt(64) len)
+    {
+        return 12;
+    };
+}
+
+void foo2(void)
+{
+    __auto_type blk = ^unsigned _BitInt(64)(int len)
+    {
+        return 12;
+    };
+}
+
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -8286,6 +8286,12 @@
       *NotEncodedT = T;
     return;
 
+  // FIXME: We should do better than this, but this is better than crashing.
+  case Type::BitInt:
+    if (NotEncodedT)
+      *NotEncodedT = T;
+    return;
+
   // We could see an undeduced auto type here during error recovery.
   // Just ignore it.
   case Type::Auto:
@@ -8293,7 +8299,6 @@
     return;
 
   case Type::Pipe:
-  case Type::BitInt:
 #define ABSTRACT_TYPE(KIND, BASE)
 #define TYPE(KIND, BASE)
 #define DEPENDENT_TYPE(KIND, BASE) \


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