PCC: verification primitives for dynamic range checks. (#7389)

* PCC: add memory type and fact annotations needed for dynamic-memory validation.

* PCC: update dynamic fact kinds, add sketch of dynamic-mem case, and add parser.

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>

* Working dynamic-range verification on x64 and aarch64.

* Fix x64 shll: output range according to bitwidth, not always-64-bit.

* Review feedback.

* Missing backtick in doc comment.

---------

Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>

cranelift/codegen/src/ir/memtype.rs

@@ -51,10 +51,6 @@
 //!
 //! Eventually we plan to also have:
 //!
-//! - A dynamic memory is an untyped blob of storage with a size given
-//! by a global value (GV). This is otherwise just like the "static
-//! memory" variant described above.
-//!
 //! - A dynamic array is a sequence of struct memory types, with a
 //! length given by a global value (GV). This is useful to model,
 //! e.g., tables.
@@ -67,7 +63,7 @@
 //! field is not null (all zero bits).
 
 use crate::ir::pcc::Fact;
-use crate::ir::Type;
+use crate::ir::{GlobalValue, Type};
 use alloc::vec::Vec;
 
 #[cfg(feature = "enable-serde")]
@@ -99,6 +95,15 @@ pub enum MemoryTypeData {
  size: u64,
  },
 
+ /// A dynamically-sized untyped blob of memory, with bound given
+ /// by a global value plus some static amount.
+ DynamicMemory {
+ /// Static part of size.
+ size: u64,
+ /// Dynamic part of size.
+ gv: GlobalValue,
+ },
+
  /// A type with no size.
  Empty,
 }
@@ -135,6 +140,9 @@ impl std::fmt::Display for MemoryTypeData {
  Self::Memory { size } => {
  write!(f, "memory {size:#x}")
  }
+ Self::DynamicMemory { size, gv } => {
+ write!(f, "dynamic_memory {}+{:#x}", gv, size)
+ }
  Self::Empty => {
  write!(f, "empty")
  }
@@ -175,6 +183,7 @@ impl MemoryTypeData {
  match self {
  Self::Struct { size, .. } => Some(*size),
  Self::Memory { size } => Some(*size),
+ Self::DynamicMemory { .. } => None,
  Self::Empty => Some(0),
  }
  }