Add a way to retrieve constant value in 128 bits

Fixes rebase fallout, makes code correct in presence of 128-bit constants.

This commit includes manual merge conflict resolution changes from a rebase by @est31.

Author: nagisa

src/librustc_const_math/int.rs

@@ -58,7 +58,8 @@ mod ubounds {
     bounds!{u128: 0,
         i8 I8MIN I8MAX i16 I16MIN I16MAX i32 I32MIN I32MAX i64 I64MIN I64MAX i128 I128MIN I128MAX
         u8 U8MIN U8MAX u16 U16MIN U16MAX u32 U32MIN U32MAX u64 U64MIN U64MAX u128 U128MIN U128MAX
-        isize IMIN IMAX usize UMIN UMAX
+        // do not add constants for isize/usize, because these are guaranteed to be wrong for
+        // arbitrary host/target combinations
     }
 }
 
@@ -78,11 +79,42 @@ mod ibounds {
     bounds!{i128,
         i8 I8MIN I8MAX i16 I16MIN I16MAX i32 I32MIN I32MAX i64 I64MIN I64MAX i128 I128MIN I128MAX
         u8 U8MIN U8MAX u16 U16MIN U16MAX u32 U32MIN U32MAX
-        isize IMIN IMAX usize UMIN UMAX
+        // do not add constants for isize/usize, because these are guaranteed to be wrong for
+        // arbitrary host/target combinations
     }
 }
 
 impl ConstInt {
+    /// Creates a new unsigned ConstInt with matching type while also checking that overflow does
+    /// not happen.
+    pub fn new_unsigned(val: u128, ty: UintTy, usize_ty: UintTy) -> Option<ConstInt> {
+        match ty {
+            UintTy::U8 if val <= ubounds::U8MAX => Some(U8(val as u8)),
+            UintTy::U16 if val <= ubounds::U16MAX => Some(U16(val as u16)),
+            UintTy::U32 if val <= ubounds::U32MAX => Some(U32(val as u32)),
+            UintTy::U64 if val <= ubounds::U64MAX => Some(U64(val as u64)),
+            UintTy::Us if val <= ubounds::U64MAX => ConstUsize::new(val as u64, usize_ty).ok()
+                .map(Usize),
+            UintTy::U128 => Some(U128(val)),
+            _ => None
+        }
+    }
+
+    /// Creates a new unsigned ConstInt with matching type while also checking that overflow does
+    /// not happen.
+    pub fn new_signed(val: i128, ty: IntTy, isize_ty: IntTy) -> Option<ConstInt> {
+        match ty {
+            IntTy::I8 if val <= ibounds::I8MAX => Some(I8(val as i8)),
+            IntTy::I16 if val <= ibounds::I16MAX => Some(I16(val as i16)),
+            IntTy::I32 if val <= ibounds::I32MAX => Some(I32(val as i32)),
+            IntTy::I64 if val <= ibounds::I64MAX => Some(I64(val as i64)),
+            IntTy::Is if val <= ibounds::I64MAX => ConstIsize::new(val as i64, isize_ty).ok()
+                .map(Isize),
+            IntTy::I128 => Some(I128(val)),
+            _ => None
+        }
+    }
+
     /// If either value is `Infer` or `InferSigned`, try to turn the value into the type of
     /// the other value. If both values have no type, don't do anything
     pub fn infer(self, other: Self) -> Result<(Self, Self), ConstMathErr> {

src/librustc_llvm/ffi.rs

@@ -582,6 +582,8 @@ extern "C" {
     pub fn LLVMConstReal(RealTy: TypeRef, N: f64) -> ValueRef;
     pub fn LLVMConstIntGetZExtValue(ConstantVal: ValueRef) -> c_ulonglong;
     pub fn LLVMConstIntGetSExtValue(ConstantVal: ValueRef) -> c_longlong;
+    pub fn LLVMRustConstInt128Get(ConstantVal: ValueRef, SExt: bool,
+                                  high: *mut u64, low: *mut u64) -> bool;
 
 
     // Operations on composite constants

src/librustc_trans/common.rs

@@ -592,20 +592,34 @@ fn is_const_integral(v: ValueRef) -> bool {
     }
 }
 
-pub fn const_to_opt_int(v: ValueRef) -> Option<i64> {
+
+#[cfg(stage0)]
+pub fn const_to_opt_u128(v: ValueRef, sign_ext: bool) -> Option<u128> {
     unsafe {
         if is_const_integral(v) {
-            Some(llvm::LLVMConstIntGetSExtValue(v))
+            if !sign_ext {
+                Some(llvm::LLVMConstIntGetZExtValue(v))
+            } else {
+                Some(llvm::LLVMConstIntGetSExtValue(v) as u64)
+            }
         } else {
             None
         }
     }
 }
 
-pub fn const_to_opt_uint(v: ValueRef) -> Option<u64> {
+#[cfg(not(stage0))]
+pub fn const_to_opt_u128(v: ValueRef, sign_ext: bool) -> Option<u128> {
     unsafe {
         if is_const_integral(v) {
-            Some(llvm::LLVMConstIntGetZExtValue(v))
+            let (mut lo, mut hi) = (0u64, 0u64);
+            let success = llvm::LLVMRustConstInt128Get(v, sign_ext,
+                                                       &mut hi as *mut u64, &mut lo as *mut u64);
+            if success {
+                Some(((hi as u128) << 64) | (lo as u128))
+            } else {
+                None
+            }
         } else {
             None
         }

src/librustc_trans/consts.rs

@@ -24,7 +24,6 @@ use monomorphize::{Instance};
 use type_::Type;
 use type_of;
 use rustc::ty;
-use rustc_i128::{i128, u128};
 
 use rustc::hir;
 

src/librustc_trans/glue.rs

@@ -346,11 +346,12 @@ pub fn size_and_align_of_dst<'a, 'tcx>(bcx: &BlockAndBuilder<'a, 'tcx>,
 
             // Choose max of two known alignments (combined value must
             // be aligned according to more restrictive of the two).
-            let align = match (const_to_opt_uint(sized_align), const_to_opt_uint(unsized_align)) {
+            let align = match (const_to_opt_u128(sized_align, false),
+                               const_to_opt_u128(unsized_align, false)) {
                 (Some(sized_align), Some(unsized_align)) => {
                     // If both alignments are constant, (the sized_align should always be), then
                     // pick the correct alignment statically.
-                    C_uint(ccx, std::cmp::max(sized_align, unsized_align))
+                    C_uint(ccx, std::cmp::max(sized_align, unsized_align) as u64)
                 }
                 _ => bcx.select(bcx.icmp(llvm::IntUGT, sized_align, unsized_align),
                                 sized_align,

src/librustc_trans/intrinsic.rs

@@ -32,6 +32,8 @@ use syntax::symbol::Symbol;
 use rustc::session::Session;
 use syntax_pos::Span;
 
+use rustc_i128::u128;
+
 use std::cmp::Ordering;
 use std::iter;
 
@@ -1019,15 +1021,15 @@ fn generic_simd_intrinsic<'a, 'tcx>(
                  in_elem, in_ty,
                  ret_ty, ret_ty.simd_type(tcx));
 
-        let total_len = in_len as u64 * 2;
+        let total_len = in_len as u128 * 2;
 
         let vector = llargs[2];
 
         let indices: Option<Vec<_>> = (0..n)
             .map(|i| {
                 let arg_idx = i;
                 let val = const_get_elt(vector, &[i as libc::c_uint]);
-                match const_to_opt_uint(val) {
+                match const_to_opt_u128(val, true) {
                     None => {
                         emit_error!("shuffle index #{} is not a constant", arg_idx);
                         None

src/librustc_trans/mir/block.rs

@@ -269,7 +269,7 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
 
             mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
                 let cond = self.trans_operand(&bcx, cond).immediate();
-                let mut const_cond = common::const_to_opt_uint(cond).map(|c| c == 1);
+                let mut const_cond = common::const_to_opt_u128(cond, false).map(|c| c == 1);
 
                 // This case can currently arise only from functions marked
                 // with #[rustc_inherit_overflow_checks] and inlined from
@@ -322,14 +322,12 @@ impl<'a, 'tcx> MirContext<'a, 'tcx> {
                         let len = self.trans_operand(&mut bcx, len).immediate();
                         let index = self.trans_operand(&mut bcx, index).immediate();
 
-                        let const_err = common::const_to_opt_uint(len).and_then(|len| {
-                            common::const_to_opt_uint(index).map(|index| {
-                                ErrKind::IndexOutOfBounds {
-                                    len: len,
-                                    index: index
-                                }
-                            })
-                        });
+                        let const_err = common::const_to_opt_u128(len, false)
+                            .and_then(|len| common::const_to_opt_u128(index, false)
+                                .map(|index| ErrKind::IndexOutOfBounds {
+                                    len: len as u64,
+                                    index: index as u64
+                                }));
 
                         let file_line = C_struct(bcx.ccx, &[filename, line], false);
                         let align = llalign_of_min(bcx.ccx, common::val_ty(file_line));

src/librustc_trans/mir/constant.rs

@@ -13,7 +13,7 @@ use rustc::middle::const_val::ConstVal;
 use rustc_const_eval::{ErrKind, ConstEvalErr, report_const_eval_err};
 use rustc_const_math::ConstInt::*;
 use rustc_const_math::ConstFloat::*;
-use rustc_const_math::{ConstInt, ConstIsize, ConstUsize, ConstMathErr};
+use rustc_const_math::{ConstInt, ConstMathErr};
 use rustc::hir::def_id::DefId;
 use rustc::infer::TransNormalize;
 use rustc::mir;
@@ -27,23 +27,23 @@ use callee::Callee;
 use common::{self, BlockAndBuilder, CrateContext, const_get_elt, val_ty};
 use common::{C_array, C_bool, C_bytes, C_floating_f64, C_integral, C_big_integral};
 use common::{C_null, C_struct, C_str_slice, C_undef, C_uint};
-use common::{const_to_opt_int, const_to_opt_uint};
+use common::{const_to_opt_u128};
 use consts;
 use monomorphize::{self, Instance};
 use type_of;
 use type_::Type;
 use value::Value;
 
-use syntax::ast;
 use syntax_pos::Span;
-use rustc_i128::u128;
 
 use std::fmt;
 use std::ptr;
 
 use super::operand::{OperandRef, OperandValue};
 use super::MirContext;
 
+use rustc_i128::{u128, i128};
+
 /// A sized constant rvalue.
 /// The LLVM type might not be the same for a single Rust type,
 /// e.g. each enum variant would have its own LLVM struct type.
@@ -431,15 +431,15 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
                     mir::ProjectionElem::Index(ref index) => {
                         let llindex = self.const_operand(index, span)?.llval;
 
-                        let iv = if let Some(iv) = common::const_to_opt_uint(llindex) {
+                        let iv = if let Some(iv) = common::const_to_opt_u128(llindex, false) {
                             iv
                         } else {
                             span_bug!(span, "index is not an integer-constant expression")
                         };
 
                         // Produce an undef instead of a LLVM assertion on OOB.
                         let len = common::const_to_uint(tr_base.len(self.ccx));
-                        let llelem = if iv < len {
+                        let llelem = if iv < len as u128 {
                             const_get_elt(base.llval, &[iv as u32])
                         } else {
                             C_undef(type_of::type_of(self.ccx, projected_ty))
@@ -797,49 +797,14 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
 
 fn to_const_int(value: ValueRef, t: Ty, tcx: TyCtxt) -> Option<ConstInt> {
     match t.sty {
-        ty::TyInt(int_type) => const_to_opt_int(value).and_then(|input| match int_type {
-            ast::IntTy::I8 => {
-                assert_eq!(input as i8 as i64, input);
-                Some(ConstInt::I8(input as i8))
-            },
-            ast::IntTy::I16 => {
-                assert_eq!(input as i16 as i64, input);
-                Some(ConstInt::I16(input as i16))
-            },
-            ast::IntTy::I32 => {
-                assert_eq!(input as i32 as i64, input);
-                Some(ConstInt::I32(input as i32))
-            },
-            ast::IntTy::I64 => {
-                Some(ConstInt::I64(input))
-            },
-            ast::IntTy::Is => {
-                ConstIsize::new(input, tcx.sess.target.int_type)
-                    .ok().map(ConstInt::Isize)
-            },
-        }),
-        ty::TyUint(uint_type) => const_to_opt_uint(value).and_then(|input| match uint_type {
-            ast::UintTy::U8 => {
-                assert_eq!(input as u8 as u64, input);
-                Some(ConstInt::U8(input as u8))
-            },
-            ast::UintTy::U16 => {
-                assert_eq!(input as u16 as u64, input);
-                Some(ConstInt::U16(input as u16))
-            },
-            ast::UintTy::U32 => {
-                assert_eq!(input as u32 as u64, input);
-                Some(ConstInt::U32(input as u32))
-            },
-            ast::UintTy::U64 => {
-                Some(ConstInt::U64(input))
-            },
-            ast::UintTy::Us => {
-                ConstUsize::new(input, tcx.sess.target.uint_type)
-                    .ok().map(ConstInt::Usize)
-            },
-        }),
-        _ => None,
+        ty::TyInt(int_type) => const_to_opt_u128(value, true)
+            .and_then(|input| ConstInt::new_signed(input as i128, int_type,
+                                                   tcx.sess.target.int_type)),
+        ty::TyUint(uint_type) => const_to_opt_u128(value, false)
+            .and_then(|input| ConstInt::new_unsigned(input, uint_type,
+                                                     tcx.sess.target.uint_type)),
+        _ => None
+
     }
 }
 

src/librustdoc/clean/mod.rs

@@ -1653,6 +1653,7 @@ impl From<ast::IntTy> for PrimitiveType {
             ast::IntTy::I16 => PrimitiveType::I16,
             ast::IntTy::I32 => PrimitiveType::I32,
             ast::IntTy::I64 => PrimitiveType::I64,
+            ast::IntTy::I128 => PrimitiveType::I128,
         }
     }
 }
@@ -1665,6 +1666,7 @@ impl From<ast::UintTy> for PrimitiveType {
             ast::UintTy::U16 => PrimitiveType::U16,
             ast::UintTy::U32 => PrimitiveType::U32,
             ast::UintTy::U64 => PrimitiveType::U64,
+            ast::UintTy::U128 => PrimitiveType::U128,
         }
     }
 }
@@ -2489,7 +2491,7 @@ impl Clean<Vec<Item>> for doctree::Impl {
 fn build_deref_target_impls(cx: &DocContext,
                             items: &[Item],
                             ret: &mut Vec<Item>) {
-    use PrimitiveType::*;
+    use self::PrimitiveType::*;
     let tcx = cx.tcx;
 
     for item in items {

src/rustllvm/RustWrapper.cpp

@@ -1456,6 +1456,22 @@ extern "C" LLVMRustLinkage LLVMRustGetLinkage(LLVMValueRef V) {
 
 extern "C" void LLVMRustSetLinkage(LLVMValueRef V, LLVMRustLinkage RustLinkage) {
     LLVMSetLinkage(V, from_rust(RustLinkage));
+
+// Returns true if both high and low were successfully set. Fails in case constant wasn’t any of
+// the common sizes (1, 8, 16, 32, 64, 128 bits)
+extern "C" bool LLVMRustConstInt128Get(LLVMValueRef CV, bool sext, uint64_t *high, uint64_t *low)
+{
+    auto C = unwrap<llvm::ConstantInt>(CV);
+    if (C->getBitWidth() > 128) { return false; }
+    APInt AP;
+    if (sext) {
+        AP = C->getValue().sextOrSelf(128);
+    } else {
+        AP = C->getValue().zextOrSelf(128);
+    }
+    *low = AP.getLoBits(64).getZExtValue();
+    *high = AP.getHiBits(64).getZExtValue();
+    return true;
 }
 
 extern "C" LLVMContextRef LLVMRustGetValueContext(LLVMValueRef V) {