Rebased PNaCl localmods in LLVM to 223109

lib/Analysis/NaCl/PNaClAllowedIntrinsics.cpp

+//===- PNaClAllowedIntrinsics.cpp - Set of allowed intrinsics -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines implementation of  class that holds set of allowed intrinsics.
+//
+// Keep 3 categories of intrinsics for now.
+// (1) Allowed always, provided the exact name and type match.
+// (2) Never allowed.
+// (3) Debug info intrinsics.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/NaCl/PNaClAllowedIntrinsics.h"
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/NaCl.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Type.h"
+
+using namespace llvm;
+
+PNaClAllowedIntrinsics::
+PNaClAllowedIntrinsics(LLVMContext *Context) : Context(Context) {
+  Type *I8Ptr = Type::getInt8PtrTy(*Context);
+  Type *I8 = Type::getInt8Ty(*Context);
+  Type *I16 = Type::getInt16Ty(*Context);
+  Type *I32 = Type::getInt32Ty(*Context);
+  Type *I64 = Type::getInt64Ty(*Context);
+  Type *Float = Type::getFloatTy(*Context);
+  Type *Double = Type::getDoubleTy(*Context);
+  Type *Vec4Float = VectorType::get(Float, 4);
+
+  // We accept bswap for a limited set of types (i16, i32, i64).  The
+  // various backends are able to generate instructions to implement
+  // the intrinsic.  Also, i16 and i64 are easy to implement as along
+  // as there is a way to do i32.
+  addIntrinsic(Intrinsic::bswap, I16);
+  addIntrinsic(Intrinsic::bswap, I32);
+  addIntrinsic(Intrinsic::bswap, I64);
+
+  // We accept cttz, ctlz, and ctpop for a limited set of types (i32, i64).
+  addIntrinsic(Intrinsic::ctlz, I32);
+  addIntrinsic(Intrinsic::ctlz, I64);
+  addIntrinsic(Intrinsic::cttz, I32);
+  addIntrinsic(Intrinsic::cttz, I64);
+  addIntrinsic(Intrinsic::ctpop, I32);
+  addIntrinsic(Intrinsic::ctpop, I64);
+
+  addIntrinsic(Intrinsic::nacl_read_tp);
+  addIntrinsic(Intrinsic::nacl_longjmp);
+  addIntrinsic(Intrinsic::nacl_setjmp);
+
+  addIntrinsic(Intrinsic::fabs, Float);
+  addIntrinsic(Intrinsic::fabs, Double);
+  addIntrinsic(Intrinsic::fabs, Vec4Float);
+
+  // For native sqrt instructions. Must guarantee when x < -0.0, sqrt(x) = NaN.
+  addIntrinsic(Intrinsic::sqrt, Float);
+  addIntrinsic(Intrinsic::sqrt, Double);
+
+  Type *AtomicTypes[] = { I8, I16, I32, I64 };
+  for (size_t T = 0, E = array_lengthof(AtomicTypes); T != E; ++T) {
+    addIntrinsic(Intrinsic::nacl_atomic_load, AtomicTypes[T]);
+    addIntrinsic(Intrinsic::nacl_atomic_store, AtomicTypes[T]);
+    addIntrinsic(Intrinsic::nacl_atomic_rmw, AtomicTypes[T]);
+    addIntrinsic(Intrinsic::nacl_atomic_cmpxchg, AtomicTypes[T]);
+  }
+  addIntrinsic(Intrinsic::nacl_atomic_fence);
+  addIntrinsic(Intrinsic::nacl_atomic_fence_all);
+
+  addIntrinsic(Intrinsic::nacl_atomic_is_lock_free);
+
+  // Stack save and restore are used to support C99 VLAs.
+  addIntrinsic(Intrinsic::stacksave);
+  addIntrinsic(Intrinsic::stackrestore);
+
+  addIntrinsic(Intrinsic::trap);
+
+  // We only allow the variants of memcpy/memmove/memset with an i32
+  // "len" argument, not an i64 argument.
+  Type *MemcpyTypes[] = { I8Ptr, I8Ptr, I32 };
+  addIntrinsic(Intrinsic::memcpy, MemcpyTypes);
+  addIntrinsic(Intrinsic::memmove, MemcpyTypes);
+  Type *MemsetTypes[] = { I8Ptr, I32 };
+  addIntrinsic(Intrinsic::memset, MemsetTypes);
+}
+
+void PNaClAllowedIntrinsics::addIntrinsic(Intrinsic::ID ID,
+                                          ArrayRef<Type *> Tys) {
+  std::string Name = Intrinsic::getName(ID, Tys);
+  FunctionType *FcnType = Intrinsic::getType(*Context, ID, Tys);
+  if (TypeMap.count(Name) >= 1) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << "Instrinsic " << Name << " defined with multiple types: "
+           << *TypeMap[Name] << " and " << *FcnType << "\n";
+    report_fatal_error(StrBuf.str());
+  }
+  TypeMap[Name] = FcnType;
+}
+
+bool PNaClAllowedIntrinsics::isAllowed(const Function *Func) {
+  if (isIntrinsicName(Func->getName()))
+    return Func->getFunctionType() == TypeMap[Func->getName()];
+  // Check to see if debugging intrinsic, which can be allowed if
+  // command-line flag set.
+  return isAllowedIntrinsicID(Func->getIntrinsicID());
+}
+
+bool PNaClAllowedIntrinsics::isAllowedIntrinsicID(unsigned ID) {
+  // (1) Allowed always, provided the exact name and type match.
+  // (2) Never allowed.
+  // (3) Debug info intrinsics.
+  //
+  // Please keep these sorted or grouped in a sensible way, within
+  // each category.
+  switch (ID) {
+    // Disallow by default.
+    default: return false;
+
+    /* The following is intentionally commented out, since the default
+       will return false.
+    // (2) Known to be never allowed.
+    case Intrinsic::not_intrinsic:
+    // Trampolines depend on a target-specific-sized/aligned buffer.
+    case Intrinsic::adjust_trampoline:
+    case Intrinsic::init_trampoline:
+    // CXX exception handling is not stable.
+    case Intrinsic::eh_dwarf_cfa:
+    case Intrinsic::eh_return_i32:
+    case Intrinsic::eh_return_i64:
+    case Intrinsic::eh_sjlj_callsite:
+    case Intrinsic::eh_sjlj_functioncontext:
+    case Intrinsic::eh_sjlj_longjmp:
+    case Intrinsic::eh_sjlj_lsda:
+    case Intrinsic::eh_sjlj_setjmp:
+    case Intrinsic::eh_typeid_for:
+    case Intrinsic::eh_unwind_init:
+    // We do not want to expose addresses to the user.
+    case Intrinsic::frameaddress:
+    case Intrinsic::returnaddress:
+    // Not supporting stack protectors.
+    case Intrinsic::stackprotector:
+    // Var-args handling is done w/out intrinsics.
+    case Intrinsic::vacopy:
+    case Intrinsic::vaend:
+    case Intrinsic::vastart:
+    // Disallow the *_with_overflow intrinsics because they return
+    // struct types.  All of them can be introduced by passing -ftrapv
+    // to Clang, which we do not support for now.  umul_with_overflow
+    // and uadd_with_overflow are introduced by Clang for C++'s new[],
+    // but ExpandArithWithOverflow expands out this use.
+    case Intrinsic::sadd_with_overflow:
+    case Intrinsic::ssub_with_overflow:
+    case Intrinsic::uadd_with_overflow:
+    case Intrinsic::usub_with_overflow:
+    case Intrinsic::smul_with_overflow:
+    case Intrinsic::umul_with_overflow:
+    // Disallow lifetime.start/end because the semantics of what
+    // arguments they accept are not very well defined, and because it
+    // would be better to do merging of stack slots in the user
+    // toolchain than in the PNaCl translator.
+    // See https://code.google.com/p/nativeclient/issues/detail?id=3443
+    case Intrinsic::lifetime_end:
+    case Intrinsic::lifetime_start:
+    case Intrinsic::invariant_end:
+    case Intrinsic::invariant_start:
+    // Some transcendental functions not needed yet.
+    case Intrinsic::cos:
+    case Intrinsic::exp:
+    case Intrinsic::exp2:
+    case Intrinsic::log:
+    case Intrinsic::log2:
+    case Intrinsic::log10:
+    case Intrinsic::pow:
+    case Intrinsic::powi:
+    case Intrinsic::sin:
+    // We run -lower-expect to convert Intrinsic::expect into branch weights
+    // and consume in the middle-end. The backend just ignores llvm.expect.
+    case Intrinsic::expect:
+    // For FLT_ROUNDS macro from float.h. It works for ARM and X86
+    // (but not MIPS). Also, wait until we add a set_flt_rounds intrinsic
+    // before we bless this.
+    case Intrinsic::flt_rounds:
+      return false;
+    */
+
+    // (3) Debug info intrinsics.
+    case Intrinsic::dbg_declare:
+    case Intrinsic::dbg_value:
+      return PNaClABIAllowDebugMetadata;
+  }
+}