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Update more references to "global variables".

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This continues the transition to "global values", which aren't
implicitly dereferenced.
This commit is contained in:
Dan Gohman
2018-06-26 13:54:46 -07:00
parent 99b9b96eee
commit 8f3c49bc6c
9 changed files with 32 additions and 112 deletions
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2
lib/codegen/src/ir/entities.rs
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@@ -185,7 +185,7 @@ pub enum AnyEntity {
Value(Value),
/// A stack slot.
StackSlot(StackSlot),
/// A Global variable.
/// A Global value.
GlobalValue(GlobalValue),
/// A jump table.
JumpTable(JumpTable),

2
lib/codegen/src/ir/function.rs
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@@ -36,7 +36,7 @@ pub struct Function {
/// be checked against.
pub stack_limit: Option<ir::GlobalValue>,
/// Global variables referenced.
/// Global values referenced.
pub global_values: PrimaryMap<ir::GlobalValue, ir::GlobalValueData>,
/// Heaps referenced.

23
lib/codegen/src/ir/globalvalue.rs
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@@ -1,4 +1,4 @@
//! Global variables.
//! Global values.
use ir::immediates::Offset32;
use ir::{ExternalName, GlobalValue};
@@ -7,34 +7,33 @@ use std::fmt;
/// Information about a global value declaration.
#[derive(Clone)]
pub enum GlobalValueData {
/// Variable is part of the VM context struct, it's address is a constant offset from the VM
/// Value is the address of a field in the VM context struct, a constant offset from the VM
/// context pointer.
VMContext {
/// Offset from the `vmctx` pointer to this global.
/// Offset from the `vmctx` pointer.
offset: Offset32,
},
/// Variable is part of a struct pointed to by another global value.
/// Value is pointed to by another global value.
///
/// The `base` global value is assumed to contain a pointer to a struct. This global
/// variable lives at an offset into the struct. The memory must be accessible, and
/// naturally aligned to hold a pointer value.
/// The `base` global value is assumed to contain a pointer. This global value is computed
/// by loading from memory at that pointer value, and then adding an offset. The memory must
/// be accessible, and naturally aligned to hold a pointer value.
Deref {
/// The base pointer global value.
base: GlobalValue,
/// Byte offset to be added to the pointer loaded from `base`.
/// Byte offset to be added to the loaded value.
offset: Offset32,
},
/// Variable is at an address identified by a symbolic name. Cretonne itself
/// does not interpret this name; it's used by embedders to link with other
/// data structures.
/// Value is identified by a symbolic name. Cretonne itself does not interpret this name;
/// it's used by embedders to link with other data structures.
Sym {
/// The symbolic name.
name: ExternalName,
/// Will this variable be defined nearby, such that it will always be a certain distance
/// Will this symbol be defined nearby, such that it will always be a certain distance
/// away, after linking? If so, references to it can avoid going through a GOT. Note that
/// symbols meant to be preemptible cannot be colocated.
colocated: bool,

70
lib/codegen/src/ir/globalvar.rs
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@@ -1,70 +0,0 @@
//! Global variables.
use ir::immediates::Offset32;
use ir::{ExternalName, GlobalValue};
use std::fmt;
/// Information about a global value declaration.
#[derive(Clone)]
pub enum GlobalValueData {
/// Variable is part of the VM context struct, it's address is a constant offset from the VM
/// context pointer.
VMContext {
/// Offset from the `vmctx` pointer to this global.
offset: Offset32,
},
/// Variable is part of a struct pointed to by another global value.
///
/// The `base` global value is assumed to contain a pointer to a struct. This global
/// variable lives at an offset into the struct. The memory must be accessible, and
/// naturally aligned to hold a pointer value.
Deref {
/// The base pointer global value.
base: GlobalValue,
/// Byte offset to be added to the pointer loaded from `base`.
offset: Offset32,
},
/// Variable is at an address identified by a symbolic name. Cretonne itself
/// does not interpret this name; it's used by embedders to link with other
/// data structures.
Sym {
/// The symbolic name.
name: ExternalName,
/// Will this variable be defined nearby, such that it will always be a certain distance
/// away, after linking? If so, references to it can avoid going through a GOT. Note that
/// symbols meant to be preemptible cannot be colocated.
colocated: bool,
},
}
impl GlobalValueData {
/// Assume that `self` is an `GlobalValueData::Sym` and return its name.
pub fn symbol_name(&self) -> &ExternalName {
match *self {
GlobalValueData::Sym { ref name, .. } => name,
_ => panic!("only symbols have names"),
}
}
}
impl fmt::Display for GlobalValueData {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
GlobalValueData::VMContext { offset } => write!(f, "vmctx{}", offset),
GlobalValueData::Deref { base, offset } => write!(f, "deref({}){}", base, offset),
GlobalValueData::Sym {
ref name,
colocated,
} => {
if colocated {
write!(f, "colocated ")?;
}
write!(f, "globalsym {}", name)
}
}
}
}

6
lib/codegen/src/ir/heap.rs
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@@ -29,8 +29,7 @@ pub enum HeapBase {
/// This feature is not yet implemented.
ReservedReg,
/// The heap base is in a global value. The variable must be accessible and naturally
/// aligned for a pointer.
/// The heap base is a global value.
GlobalValue(GlobalValue),
}
@@ -39,8 +38,7 @@ pub enum HeapBase {
pub enum HeapStyle {
/// A dynamic heap can be relocated to a different base address when it is grown.
Dynamic {
/// Global variable holding the current bound of the heap in bytes. It is
/// required to be accessible and naturally aligned for a pointer-sized integer.
/// Global value providing the current bound of the heap in bytes.
bound_gv: GlobalValue,
},

2
lib/codegen/src/verifier/mod.rs
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@@ -41,7 +41,7 @@
//! - All return instructions must have return value operands matching the current
//! function signature.
//!
//! Global variables
//! Global values
//!
//! - Detect cycles in deref(base) declarations.
//!