Switch to MIR-based translation by default.

configure

@@ -609,7 +609,7 @@ opt dist-host-only 0 "only install bins for the host architecture"
 opt inject-std-version 1 "inject the current compiler version of libstd into programs"
 opt llvm-version-check 1 "check if the LLVM version is supported, build anyway"
 opt rustbuild 0 "use the rust and cargo based build system"
-opt orbit 0 "get MIR where it belongs - everywhere; most importantly, in orbit"
+opt orbit 1 "get MIR where it belongs - everywhere; most importantly, in orbit"
 opt codegen-tests 1 "run the src/test/codegen tests"
 opt option-checking 1 "complain about unrecognized options in this configure script"
 opt ninja 0 "build LLVM using the Ninja generator (for MSVC, requires building in the correct environment)"
@@ -733,7 +733,7 @@ if [ -n "$CFG_ENABLE_DEBUG_ASSERTIONS" ]; then putvar CFG_ENABLE_DEBUG_ASSERTION
 if [ -n "$CFG_ENABLE_DEBUGINFO" ]; then putvar CFG_ENABLE_DEBUGINFO; fi
 if [ -n "$CFG_ENABLE_DEBUG_JEMALLOC" ]; then putvar CFG_ENABLE_DEBUG_JEMALLOC; fi
 
-if [ -n "$CFG_ENABLE_ORBIT" ]; then putvar CFG_ENABLE_ORBIT; fi
+if [ -n "$CFG_DISABLE_ORBIT" ]; then putvar CFG_DISABLE_ORBIT; fi
 
 step_msg "looking for build programs"
 

mk/main.mk

@@ -162,9 +162,9 @@ ifdef CFG_ENABLE_DEBUGINFO
   CFG_RUSTC_FLAGS += -g
 endif
 
-ifdef CFG_ENABLE_ORBIT
-  $(info cfg: launching MIR (CFG_ENABLE_ORBIT))
-  CFG_RUSTC_FLAGS += -Z orbit
+ifdef CFG_DISABLE_ORBIT
+  $(info cfg: HOLD HOLD HOLD (CFG_DISABLE_ORBIT))
+  CFG_RUSTC_FLAGS += -Z orbit=off
 endif
 
 ifdef SAVE_TEMPS

src/doc/book/lang-items.md

@@ -15,7 +15,7 @@ For example, `Box` pointers require two lang items, one for allocation
 and one for deallocation. A freestanding program that uses the `Box`
 sugar for dynamic allocations via `malloc` and `free`:
 
-```rust
+```rust,ignore
 #![feature(lang_items, box_syntax, start, libc)]
 #![no_std]
 

src/librustc/session/config.rs

@@ -463,6 +463,8 @@ macro_rules! options {
         pub const parse_bool: Option<&'static str> = None;
         pub const parse_opt_bool: Option<&'static str> =
             Some("one of: `y`, `yes`, `on`, `n`, `no`, or `off`");
+        pub const parse_all_bool: Option<&'static str> =
+            Some("one of: `y`, `yes`, `on`, `n`, `no`, or `off`");
         pub const parse_string: Option<&'static str> = Some("a string");
         pub const parse_opt_string: Option<&'static str> = Some("a string");
         pub const parse_list: Option<&'static str> = Some("a space-separated list of strings");
@@ -512,6 +514,25 @@ macro_rules! options {
             }
         }
 
+        fn parse_all_bool(slot: &mut bool, v: Option<&str>) -> bool {
+            match v {
+                Some(s) => {
+                    match s {
+                        "n" | "no" | "off" => {
+                            *slot = false;
+                        }
+                        "y" | "yes" | "on" => {
+                            *slot = true;
+                        }
+                        _ => { return false; }
+                    }
+
+                    true
+                },
+                None => { *slot = true; true }
+            }
+        }
+
         fn parse_opt_string(slot: &mut Option<String>, v: Option<&str>) -> bool {
             match v {
                 Some(s) => { *slot = Some(s.to_string()); true },
@@ -756,7 +777,7 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "dump MIR state at various points in translation"),
     dump_mir_dir: Option<String> = (None, parse_opt_string,
           "the directory the MIR is dumped into"),
-    orbit: bool = (false, parse_bool,
+    orbit: bool = (true, parse_all_bool,
           "get MIR where it belongs - everywhere; most importantly, in orbit"),
 }
 

src/librustc_trans/mir/rvalue.rs

@@ -244,18 +244,46 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                             }
                         }
                     }
-                    mir::CastKind::Misc if common::type_is_immediate(bcx.ccx(), operand.ty) => {
+                    mir::CastKind::Misc if common::type_is_fat_ptr(bcx.tcx(), operand.ty) => {
+                        let ll_cast_ty = type_of::immediate_type_of(bcx.ccx(), cast_ty);
+                        let ll_from_ty = type_of::immediate_type_of(bcx.ccx(), operand.ty);
+                        if let OperandValue::Pair(data_ptr, meta_ptr) = operand.val {
+                            if common::type_is_fat_ptr(bcx.tcx(), cast_ty) {
+                                let ll_cft = ll_cast_ty.field_types();
+                                let ll_fft = ll_from_ty.field_types();
+                                let data_cast = bcx.pointercast(data_ptr, ll_cft[0]);
+                                assert_eq!(ll_cft[1].kind(), ll_fft[1].kind());
+                                OperandValue::Pair(data_cast, meta_ptr)
+                            } else { // cast to thin-ptr
+                                // Cast of fat-ptr to thin-ptr is an extraction of data-ptr and
+                                // pointer-cast of that pointer to desired pointer type.
+                                let llval = bcx.pointercast(data_ptr, ll_cast_ty);
+                                OperandValue::Immediate(llval)
+                            }
+                        } else {
+                            bug!("Unexpected non-Pair operand")
+                        }
+                    }
+                    mir::CastKind::Misc => {
                         debug_assert!(common::type_is_immediate(bcx.ccx(), cast_ty));
                         let r_t_in = CastTy::from_ty(operand.ty).expect("bad input type for cast");
                         let r_t_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
                         let ll_t_in = type_of::immediate_type_of(bcx.ccx(), operand.ty);
                         let ll_t_out = type_of::immediate_type_of(bcx.ccx(), cast_ty);
-                        let llval = operand.immediate();
-                        let signed = if let CastTy::Int(IntTy::CEnum) = r_t_in {
+                        let (llval, signed) = if let CastTy::Int(IntTy::CEnum) = r_t_in {
                             let repr = adt::represent_type(bcx.ccx(), operand.ty);
-                            adt::is_discr_signed(&repr)
+                            let discr = match operand.val {
+                                OperandValue::Immediate(llval) => llval,
+                                OperandValue::Ref(llptr) => {
+                                    bcx.with_block(|bcx| {
+                                        adt::trans_get_discr(bcx, &repr, llptr, None, true)
+                                    })
+                                }
+                                OperandValue::Pair(..) => bug!("Unexpected Pair operand")
+                            };
+                            (discr, adt::is_discr_signed(&repr))
                         } else {
-                            operand.ty.is_signed()
+                            (operand.immediate(), operand.ty.is_signed())
                         };
 
                         let newval = match (r_t_in, r_t_out) {
@@ -304,26 +332,6 @@ impl<'bcx, 'tcx> MirContext<'bcx, 'tcx> {
                         };
                         OperandValue::Immediate(newval)
                     }
-                    mir::CastKind::Misc => { // Casts from a fat-ptr.
-                        let ll_cast_ty = type_of::immediate_type_of(bcx.ccx(), cast_ty);
-                        let ll_from_ty = type_of::immediate_type_of(bcx.ccx(), operand.ty);
-                        if let OperandValue::Pair(data_ptr, meta_ptr) = operand.val {
-                            if common::type_is_fat_ptr(bcx.tcx(), cast_ty) {
-                                let ll_cft = ll_cast_ty.field_types();
-                                let ll_fft = ll_from_ty.field_types();
-                                let data_cast = bcx.pointercast(data_ptr, ll_cft[0]);
-                                assert_eq!(ll_cft[1].kind(), ll_fft[1].kind());
-                                OperandValue::Pair(data_cast, meta_ptr)
-                            } else { // cast to thin-ptr
-                                // Cast of fat-ptr to thin-ptr is an extraction of data-ptr and
-                                // pointer-cast of that pointer to desired pointer type.
-                                let llval = bcx.pointercast(data_ptr, ll_cast_ty);
-                                OperandValue::Immediate(llval)
-                            }
-                        } else {
-                            bug!("Unexpected non-Pair operand")
-                        }
-                    }
                 };
                 let operand = OperandRef {
                     val: val,

src/test/run-pass/issue-14936.rs

@@ -28,7 +28,8 @@ macro_rules! demo {
             unsafe {
                 asm!("mov ($1), $0"
                      : $output_constraint (*wrap(&mut x, "out", &mut history))
-                     : "r"(&wrap(y, "in", &mut history)));
+                     : "r"(&wrap(y, "in", &mut history))
+                     :: "volatile");
             }
             assert_eq!((x,y), (1,1));
             let b: &[_] = &["out", "in"];

src/test/run-pass/issue-28950.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z orbit=off
+// (blows the stack with MIR trans and no optimizations)
+
 // Tests that the `vec!` macro does not overflow the stack when it is
 // given data larger than the stack.