T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add a readonly flag for loads (#562)

Browse Source 
* Add readonly MemFlag

* Add readonly flag verifier check

* Make global loads readonly

* Fix gvn to consider readonly loads
This commit is contained in:
Lachlan Sneff
2018-10-23 00:50:09 -04:00
committed by Dan Gohman
parent 3ec21459c5
commit 586a8835e9
9 changed files with 120 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
lib/codegen/src/legalizer/globalvalue.rs
View File

@@ -38,7 +38,8 @@ pub fn expand_global_value(
base,
offset,
global_type,
} => load_addr(inst, func, base, offset, global_type, isa),
readonly,
} => load_addr(inst, func, base, offset, global_type, readonly, isa),
ir::GlobalValueData::Symbol { .. } => symbol(inst, func, gv, isa),
}
}
@@ -88,6 +89,7 @@ fn load_addr(
base: ir::GlobalValue,
offset: ir::immediates::Offset32,
global_type: ir::Type,
readonly: bool,
isa: &TargetIsa,
) {
// We need to load a pointer from the `base` global value, so insert a new `global_value`
@@ -107,10 +109,13 @@ fn load_addr(
pos.ins().global_value(ptr_ty, base)
};
// Global-value loads are always notrap and aligned.
// Global-value loads are always notrap and aligned. They may be readonly.
let mut mflags = ir::MemFlags::new();
mflags.set_notrap();
mflags.set_aligned();
if readonly {
mflags.set_readonly();
}
// Perform the load.
pos.func