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Ensure that statics are always ByRef

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This commit is contained in:
Oliver Schneider 2018-05-12 18:47:20 +02:00 committed by Oliver Schneider
parent c95e1cccc9
commit 8b99c61701
3 changed files with 69 additions and 133 deletions
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49
src/librustc_codegen_llvm/mir/constant.rs
View File

@ -81,49 +81,6 @@ pub fn primval_to_llvm(cx: &CodegenCx,
} }
} }
fn const_value_to_llvm<'tcx>(cx: &CodegenCx<'_, 'tcx>, val: ConstValue, ty: Ty<'tcx>) -> ValueRef {
let layout = cx.layout_of(ty);
if layout.is_zst() {
return C_undef(layout.immediate_llvm_type(cx));
}
match val {
ConstValue::ByVal(x) => {
let scalar = match layout.abi {
layout::Abi::Scalar(ref x) => x,
_ => bug!("const_value_to_llvm: invalid ByVal layout: {:#?}", layout)
};
primval_to_llvm(
cx,
x,
scalar,
layout.immediate_llvm_type(cx),
)
},
ConstValue::ByValPair(a, b) => {
let (a_scalar, b_scalar) = match layout.abi {
layout::Abi::ScalarPair(ref a, ref b) => (a, b),
_ => bug!("const_value_to_llvm: invalid ByValPair layout: {:#?}", layout)
};
let a_llval = primval_to_llvm(
cx,
a,
a_scalar,
layout.scalar_pair_element_llvm_type(cx, 0),
);
let b_llval = primval_to_llvm(
cx,
b,
b_scalar,
layout.scalar_pair_element_llvm_type(cx, 1),
);
C_struct(cx, &[a_llval, b_llval], false)
},
ConstValue::ByRef(alloc) => const_alloc_to_llvm(cx, alloc),
}
}
pub fn const_alloc_to_llvm(cx: &CodegenCx, alloc: &Allocation) -> ValueRef { pub fn const_alloc_to_llvm(cx: &CodegenCx, alloc: &Allocation) -> ValueRef {
let mut llvals = Vec::with_capacity(alloc.relocations.len() + 1); let mut llvals = Vec::with_capacity(alloc.relocations.len() + 1);
let layout = cx.data_layout(); let layout = cx.data_layout();
@ -171,11 +128,11 @@ pub fn codegen_static_initializer<'a, 'tcx>(
let param_env = ty::ParamEnv::reveal_all(); let param_env = ty::ParamEnv::reveal_all();
let static_ = cx.tcx.const_eval(param_env.and(cid))?; let static_ = cx.tcx.const_eval(param_env.and(cid))?;
let val = match static_.val { let alloc = match static_.val {
ConstVal::Value(val) => val, ConstVal::Value(ConstValue::ByRef(alloc)) => alloc,
_ => bug!("static const eval returned {:#?}", static_), _ => bug!("static const eval returned {:#?}", static_),
}; };
Ok(const_value_to_llvm(cx, val, static_.ty)) Ok(const_alloc_to_llvm(cx, alloc))
} }
impl<'a, 'tcx> FunctionCx<'a, 'tcx> { impl<'a, 'tcx> FunctionCx<'a, 'tcx> {

145
src/librustc_mir/interpret/const_eval.rs
View File

@ -98,59 +98,32 @@ pub fn value_to_const_value<'tcx>(
mut val: Value, mut val: Value,
ty: Ty<'tcx>, ty: Ty<'tcx>,
) -> &'tcx ty::Const<'tcx> { ) -> &'tcx ty::Const<'tcx> {
let result = (|| { let val = (|| {
// Convert to ByVal or ByValPair if possible // Convert to ByVal or ByValPair if possible
if let Value::ByRef(ptr, align) = val { if let Value::ByRef(ptr, align) = val {
if let Some(read_val) = ecx.try_read_value(ptr, align, ty)? { if let Some(read_val) = ecx.try_read_value(ptr, align, ty)? {
val = read_val; val = read_val;
} }
} }
match val {
let layout = ecx.tcx.layout_of(ty::ParamEnv::reveal_all().and(ty)).unwrap(); Value::ByVal(val) => Ok(ConstValue::ByVal(val)),
Value::ByValPair(a, b) => Ok(ConstValue::ByValPair(a, b)),
if layout.is_zst() { Value::ByRef(ptr, align) => {
return Ok(ty::Const::from_const_value( let ptr = ptr.primval.to_ptr().unwrap();
ecx.tcx.tcx, assert_eq!(ptr.offset, 0);
ConstValue::ByVal(PrimVal::Undef), let alloc = ecx.memory.get(ptr.alloc_id)?;
ty)); assert!(alloc.align.abi() >= layout.align.abi());
assert!(alloc.bytes.len() as u64 == layout.size.bytes());
let mut alloc = alloc.clone();
// The align field is meaningless for values, so just use the layout's align
alloc.align = layout.align;
let alloc = ecx.tcx.intern_const_alloc(alloc);
Ok(ConstValue::ByRef(alloc))
}
} }
let val = match layout.abi {
layout::Abi::Scalar(..) => {
if let Value::ByVal(val) = val {
ConstValue::ByVal(val)
} else {
bug!("expected ByVal value, got {:?}", val);
}
}
layout::Abi::ScalarPair(..) => {
if let Value::ByValPair(a, b) = val {
ConstValue::ByValPair(a, b)
} else {
bug!("expected ByValPair value, got {:?}", val);
}
}
_ => {
if let Value::ByRef(ptr, _) = val {
let ptr = ptr.primval.to_ptr().unwrap();
assert_eq!(ptr.offset, 0);
let alloc = ecx.memory.get(ptr.alloc_id)?;
assert!(alloc.align.abi() >= layout.align.abi());
assert!(alloc.bytes.len() as u64 == layout.size.bytes());
let mut alloc = alloc.clone();
// The align field is meaningless for values, so just use the layout's align
alloc.align = layout.align;
let alloc = ecx.tcx.intern_const_alloc(alloc);
ConstValue::ByRef(alloc)
} else {
bug!("expected ByRef value, got {:?}", val);
}
},
};
Ok(ty::Const::from_const_value(ecx.tcx.tcx, val, ty))
})(); })();
match result { match result {
Ok(v) => v, Ok(v) => ty::Const::from_const_value(tcx, val, ty),
Err(mut err) => { Err(mut err) => {
ecx.report(&mut err, true, None); ecx.report(&mut err, true, None);
bug!("miri error occured when converting Value to ConstValue") bug!("miri error occured when converting Value to ConstValue")
@ -182,49 +155,49 @@ fn eval_body_using_ecx<'a, 'mir, 'tcx>(
) -> EvalResult<'tcx, (Value, Pointer, Ty<'tcx>)> { ) -> EvalResult<'tcx, (Value, Pointer, Ty<'tcx>)> {
debug!("eval_body: {:?}, {:?}", cid, param_env); debug!("eval_body: {:?}, {:?}", cid, param_env);
let tcx = ecx.tcx.tcx; let tcx = ecx.tcx.tcx;
let mut mir = match mir { let mut mir = match mir {
Some(mir) => mir, Some(mir) => mir,
None => ecx.load_mir(cid.instance.def)?, None => ecx.load_mir(cid.instance.def)?,
}; };
if let Some(index) = cid.promoted { if let Some(index) = cid.promoted {
mir = &mir.promoted[index]; mir = &mir.promoted[index];
} }
let layout = ecx.layout_of(mir.return_ty().subst(tcx, cid.instance.substs))?; let layout = ecx.layout_of(mir.return_ty().subst(tcx, cid.instance.substs))?;
assert!(!layout.is_unsized()); assert!(!layout.is_unsized());
let ptr = ecx.memory.allocate( let ptr = ecx.memory.allocate(
layout.size.bytes(), layout.size.bytes(),
layout.align, layout.align,
None, None,
)?; )?;
let internally_mutable = !layout.ty.is_freeze(tcx, param_env, mir.span); let internally_mutable = !layout.ty.is_freeze(tcx, param_env, mir.span);
let mutability = tcx.is_static(cid.instance.def_id()); let is_static = tcx.is_static(cid.instance.def_id());
let mutability = if mutability == Some(hir::Mutability::MutMutable) || internally_mutable { let mutability = if is_static == Some(hir::Mutability::MutMutable) || internally_mutable {
Mutability::Mutable Mutability::Mutable
} else { } else {
Mutability::Immutable Mutability::Immutable
}; };
let cleanup = StackPopCleanup::MarkStatic(mutability); let cleanup = StackPopCleanup::MarkStatic(mutability);
let name = ty::tls::with(|tcx| tcx.item_path_str(cid.instance.def_id())); let name = ty::tls::with(|tcx| tcx.item_path_str(cid.instance.def_id()));
let prom = cid.promoted.map_or(String::new(), |p| format!("::promoted[{:?}]", p)); let prom = cid.promoted.map_or(String::new(), |p| format!("::promoted[{:?}]", p));
trace!("const_eval: pushing stack frame for global: {}{}", name, prom); trace!("const_eval: pushing stack frame for global: {}{}", name, prom);
assert!(mir.arg_count == 0); assert!(mir.arg_count == 0);
ecx.push_stack_frame( ecx.push_stack_frame(
cid.instance, cid.instance,
mir.span, mir.span,
mir, mir,
Place::from_ptr(ptr, layout.align), Place::from_ptr(ptr, layout.align),
cleanup, cleanup,
)?; )?;
while ecx.step()? {} while ecx.step()? {}
let ptr = ptr.into(); let ptr = ptr.into();
// always try to read the value and report errors // always try to read the value and report errors
let value = match ecx.try_read_value(ptr, layout.align, layout.ty)? { let value = match ecx.try_read_value(ptr, layout.align, layout.ty)? {
Some(val) => val, Some(val) if is_static.is_none() => val,
// point at the allocation // point at the allocation
_ => Value::ByRef(ptr, layout.align), _ => Value::ByRef(ptr, layout.align),
}; };
Ok((value, ptr, layout.ty)) Ok((value, ptr, layout.ty))
} }
pub struct CompileTimeEvaluator; pub struct CompileTimeEvaluator;

8
src/test/codegen/link_section.rs
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@ -12,11 +12,17 @@
#![crate_type = "lib"] #![crate_type = "lib"]
// CHECK: @VAR1 = constant i32 1, section ".test_one" // CHECK: @VAR1 = constant <{ [4 x i8] }> <{ [4 x i8] c"\01\00\00\00" }>, section ".test_one"
#[no_mangle] #[no_mangle]
#[link_section = ".test_one"] #[link_section = ".test_one"]
#[cfg(target_endian = "little")]
pub static VAR1: u32 = 1; pub static VAR1: u32 = 1;
#[no_mangle]
#[link_section = ".test_one"]
#[cfg(target_endian = "big")]
pub static VAR1: u32 = 0x01000000;
pub enum E { pub enum E {
A(u32), A(u32),
B(f32) B(f32)