Commit d2934179 authored by serge-sans-paille's avatar serge-sans-paille
Browse files

Add __warn_memset_zero_len builtin as a workaround for glibc issue 

Glibc issue: https://sourceware.org/bugzilla/show_bug.cgi?id=25399
The fix consist in considering the missing function as a builtin lowered to a nop.

Differential Revision: https://reviews.llvm.org/D72869
parent d437fba8

clang/include/clang/Basic/Builtins.def

+3 −0
Original line number Diff line number Diff line
@@ -788,6 +788,9 @@ BUILTIN(__builtin_abort, "v", "Fnr") 
BUILTIN(__builtin_index, "c*cC*i", "Fn")

BUILTIN(__builtin_rindex, "c*cC*i", "Fn")



// ignored glibc builtin, see https://sourceware.org/bugzilla/show_bug.cgi?id=25399

BUILTIN(__warn_memset_zero_len, "v", "nU")



// Microsoft builtins.  These are only active with -fms-extensions.

LANGBUILTIN(_alloca,          "v*z", "n", ALL_MS_LANGUAGES)

LANGBUILTIN(__annotation,     "wC*.","n", ALL_MS_LANGUAGES)

clang/lib/CodeGen/CGBuiltin.cpp

+2 −0
Original line number Diff line number Diff line
@@ -3222,6 +3222,8 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID, 
        Builder.CreateZExt(EmitSignBit(*this, EmitScalarExpr(E->getArg(0))),

                           ConvertType(E->getType())));

  }

  case Builtin::BI__warn_memset_zero_len:

    return RValue::getIgnored();

  case Builtin::BI__annotation: {

    // Re-encode each wide string to UTF8 and make an MDString.

    SmallVector<Metadata *, 1> Strings;

clang/test/CodeGen/builtins.c

+7 −0
Original line number Diff line number Diff line
@@ -453,6 +453,13 @@ void test_builtin_launder(int *p) { 
  int *d = __builtin_launder(p);

}



// __warn_memset_zero_len should be NOP, see https://sourceware.org/bugzilla/show_bug.cgi?id=25399

// CHECK-LABEL: define void @test___warn_memset_zero_len

void test___warn_memset_zero_len() {

  // CHECK-NOT: @__warn_memset_zero_len

  __warn_memset_zero_len();

}



// Behavior of __builtin_os_log differs between platforms, so only test on X86

#ifdef __x86_64__