[clang] 911add1 - Disable _ExtInt by default

[Erich Keane via cfe-commits]

Author: Erich Keane
Date: 2020-04-29T13:48:12-07:00
New Revision: 911add149af563a5a61458de0dd730e3f5348623

URL: https://github.com/llvm/llvm-project/commit/911add149af563a5a61458de0dd730e3f5348623
DIFF: https://github.com/llvm/llvm-project/commit/911add149af563a5a61458de0dd730e3f5348623.diff

LOG: Disable _ExtInt by default

Since the _ExtInt type got into the repo, we've discovered that the ABI
implications weren't completely understood. The other architectures are
going to be audited (see D79118), however downstream targets aren't
going to benefit from this audit.

This patch disables the _ExtInt type by default and makes the
target-info an opt-in.  As it is audited, I'll re-enable these for all
of our default targets.

Added: 
    clang/test/Sema/ext-int-not-supported.c

Modified: 
    clang/include/clang/Basic/TargetInfo.h
    clang/lib/Basic/Targets/X86.h
    clang/lib/Sema/SemaType.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index ab4795404071..910a4d6846aa 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -547,6 +547,12 @@ class TargetInfo : public virtual TransferrableTargetInfo,
     return (getPointerWidth(0) >= 64) || getTargetOpts().ForceEnableInt128;
   } // FIXME
 
+  /// Determine whether the _ExtInt type is supported on this target. This
+  /// limitation is put into place for ABI reasons.
+  virtual bool hasExtIntType() const {
+    return false;
+  }
+
   /// Determine whether _Float16 is supported on this target.
   virtual bool hasLegalHalfType() const { return HasLegalHalfType; }
 

diff  --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index a68109a604d5..39ccac96a49d 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -435,6 +435,8 @@ class LLVM_LIBRARY_VISIBILITY X86_32TargetInfo : public X86TargetInfo {
   }
 
   ArrayRef<Builtin::Info> getTargetBuiltins() const override;
+
+  bool hasExtIntType() const override { return true; }
 };
 
 class LLVM_LIBRARY_VISIBILITY NetBSDI386TargetInfo
@@ -737,6 +739,8 @@ class LLVM_LIBRARY_VISIBILITY X86_64TargetInfo : public X86TargetInfo {
   }
 
   ArrayRef<Builtin::Info> getTargetBuiltins() const override;
+
+  bool hasExtIntType() const override { return true; }
 };
 
 // x86-64 Windows target

diff  --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index a96e1c1e6572..338e33589b1d 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1443,6 +1443,9 @@ static QualType ConvertDeclSpecToType(TypeProcessingState &state) {
     break;
   }
   case DeclSpec::TST_extint: {
+    if (!S.Context.getTargetInfo().hasExtIntType())
+      S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_unsupported)
+        << "_ExtInt";
     Result = S.BuildExtIntType(DS.getTypeSpecSign() == TSS_unsigned,
                                DS.getRepAsExpr(), DS.getBeginLoc());
     if (Result.isNull()) {

diff  --git a/clang/test/Sema/ext-int-not-supported.c b/clang/test/Sema/ext-int-not-supported.c
new file mode 100644
index 000000000000..23610b9941e4
--- /dev/null
+++ b/clang/test/Sema/ext-int-not-supported.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -triple armv7 -fsyntax-only -verify %s
+
+void foo() {
+  _ExtInt(33) a; // expected-error{{_ExtInt is not supported on this target}}
+}