diff --git a/lib/codegen/src/dominator_tree.rs b/lib/codegen/src/dominator_tree.rs
index a246f671bc..2198fbf2bf 100644
--- a/lib/codegen/src/dominator_tree.rs
+++ b/lib/codegen/src/dominator_tree.rs
@@ -1,6 +1,6 @@
 //! A Dominator Tree represented as mappings of Ebbs to their immediate dominator.
 
-use entity::EntityMap;
+use entity::SecondaryMap;
 use flowgraph::{BasicBlock, ControlFlowGraph};
 use ir::instructions::BranchInfo;
 use ir::{Ebb, ExpandedProgramPoint, Function, Inst, Layout, ProgramOrder, Value};
@@ -38,7 +38,7 @@ struct DomNode {
 
 /// The dominator tree for a single function.
 pub struct DominatorTree {
-    nodes: EntityMap<Ebb, DomNode>,
+    nodes: SecondaryMap<Ebb, DomNode>,
 
     /// CFG post-order of all reachable EBBs.
     postorder: Vec<Ebb>,
@@ -217,7 +217,7 @@ impl DominatorTree {
     /// function.
     pub fn new() -> Self {
         Self {
-            nodes: EntityMap::new(),
+            nodes: SecondaryMap::new(),
             postorder: Vec::new(),
             stack: Vec::new(),
             valid: false,
@@ -505,7 +505,7 @@ impl DominatorTree {
 /// The information in this auxillary data structure is not easy to update when the control flow
 /// graph changes, which is why it is kept separate.
 pub struct DominatorTreePreorder {
-    nodes: EntityMap<Ebb, ExtraNode>,
+    nodes: SecondaryMap<Ebb, ExtraNode>,
 
     // Scratch memory used by `compute_postorder()`.
     stack: Vec<Ebb>,
@@ -533,7 +533,7 @@ impl DominatorTreePreorder {
     /// Create a new blank `DominatorTreePreorder`.
     pub fn new() -> Self {
         Self {
-            nodes: EntityMap::new(),
+            nodes: SecondaryMap::new(),
             stack: Vec::new(),
         }
     }
diff --git a/lib/codegen/src/flowgraph.rs b/lib/codegen/src/flowgraph.rs
index b84da7cd0b..97c3f932f5 100644
--- a/lib/codegen/src/flowgraph.rs
+++ b/lib/codegen/src/flowgraph.rs
@@ -24,7 +24,7 @@
 //! and `(Ebb0, jmp Ebb2)` respectively.
 
 use bforest;
-use entity::EntityMap;
+use entity::SecondaryMap;
 use ir::instructions::BranchInfo;
 use ir::{Ebb, Function, Inst};
 use std::mem;
@@ -72,7 +72,7 @@ struct CFGNode {
 /// and successors where predecessors are basic blocks and successors are
 /// extended basic blocks.
 pub struct ControlFlowGraph {
-    data: EntityMap<Ebb, CFGNode>,
+    data: SecondaryMap<Ebb, CFGNode>,
     pred_forest: bforest::MapForest<Inst, Ebb>,
     succ_forest: bforest::SetForest<Ebb>,
     valid: bool,
@@ -82,7 +82,7 @@ impl ControlFlowGraph {
     /// Allocate a new blank control flow graph.
     pub fn new() -> Self {
         Self {
-            data: EntityMap::new(),
+            data: SecondaryMap::new(),
             valid: false,
             pred_forest: bforest::MapForest::new(),
             succ_forest: bforest::SetForest::new(),
diff --git a/lib/codegen/src/ir/dfg.rs b/lib/codegen/src/ir/dfg.rs
index bb8ddbe9c4..7bcf17e949 100644
--- a/lib/codegen/src/ir/dfg.rs
+++ b/lib/codegen/src/ir/dfg.rs
@@ -1,6 +1,6 @@
 //! Data flow graph tracking Instructions, Values, and EBBs.
 
-use entity::{self, EntityMap, PrimaryMap};
+use entity::{self, PrimaryMap, SecondaryMap};
 use ir;
 use ir::builder::ReplaceBuilder;
 use ir::extfunc::ExtFuncData;
@@ -34,7 +34,7 @@ pub struct DataFlowGraph {
     ///
     /// This map gets resized automatically by `make_inst()` so it is always in sync with the
     /// primary `insts` map.
-    results: EntityMap<Inst, ValueList>,
+    results: SecondaryMap<Inst, ValueList>,
 
     /// Extended basic blocks in the function and their parameters.
     ///
@@ -67,7 +67,7 @@ impl DataFlowGraph {
     pub fn new() -> Self {
         Self {
             insts: PrimaryMap::new(),
-            results: EntityMap::new(),
+            results: SecondaryMap::new(),
             ebbs: PrimaryMap::new(),
             value_lists: ValueListPool::new(),
             values: PrimaryMap::new(),
@@ -90,7 +90,7 @@ impl DataFlowGraph {
     /// Get the total number of instructions created in this function, whether they are currently
     /// inserted in the layout or not.
     ///
-    /// This is intended for use with `EntityMap::with_capacity`.
+    /// This is intended for use with `SecondaryMap::with_capacity`.
     pub fn num_insts(&self) -> usize {
         self.insts.len()
     }
@@ -103,7 +103,7 @@ impl DataFlowGraph {
     /// Get the total number of extended basic blocks created in this function, whether they are
     /// currently inserted in the layout or not.
     ///
-    /// This is intended for use with `EntityMap::with_capacity`.
+    /// This is intended for use with `SecondaryMap::with_capacity`.
     pub fn num_ebbs(&self) -> usize {
         self.ebbs.len()
     }
diff --git a/lib/codegen/src/ir/function.rs b/lib/codegen/src/ir/function.rs
index cf9cbdbe29..d15de64c3a 100644
--- a/lib/codegen/src/ir/function.rs
+++ b/lib/codegen/src/ir/function.rs
@@ -4,7 +4,7 @@
 //! instructions.
 
 use binemit::CodeOffset;
-use entity::{EntityMap, PrimaryMap};
+use entity::{PrimaryMap, SecondaryMap};
 use ir;
 use ir::{DataFlowGraph, ExternalName, Layout, Signature};
 use ir::{
@@ -84,10 +84,10 @@ impl Function {
             jump_tables: PrimaryMap::new(),
             dfg: DataFlowGraph::new(),
             layout: Layout::new(),
-            encodings: EntityMap::new(),
-            locations: EntityMap::new(),
-            offsets: EntityMap::new(),
-            srclocs: EntityMap::new(),
+            encodings: SecondaryMap::new(),
+            locations: SecondaryMap::new(),
+            offsets: SecondaryMap::new(),
+            srclocs: SecondaryMap::new(),
         }
     }
 
diff --git a/lib/codegen/src/ir/layout.rs b/lib/codegen/src/ir/layout.rs
index a9dc08d786..a251822847 100644
--- a/lib/codegen/src/ir/layout.rs
+++ b/lib/codegen/src/ir/layout.rs
@@ -3,7 +3,7 @@
 //! The order of extended basic blocks in a function and the order of instructions in an EBB is
 //! determined by the `Layout` data structure defined in this module.
 
-use entity::EntityMap;
+use entity::SecondaryMap;
 use ir::progpoint::{ExpandedProgramPoint, ProgramOrder};
 use ir::{Ebb, Inst};
 use packed_option::PackedOption;
@@ -28,11 +28,11 @@ use timing;
 pub struct Layout {
     /// Linked list nodes for the layout order of EBBs Forms a doubly linked list, terminated in
     /// both ends by `None`.
-    ebbs: EntityMap<Ebb, EbbNode>,
+    ebbs: SecondaryMap<Ebb, EbbNode>,
 
     /// Linked list nodes for the layout order of instructions. Forms a double linked list per EBB,
     /// terminated in both ends by `None`.
-    insts: EntityMap<Inst, InstNode>,
+    insts: SecondaryMap<Inst, InstNode>,
 
     /// First EBB in the layout order, or `None` when no EBBs have been laid out.
     first_ebb: Option<Ebb>,
@@ -45,8 +45,8 @@ impl Layout {
     /// Create a new empty `Layout`.
     pub fn new() -> Self {
         Self {
-            ebbs: EntityMap::new(),
-            insts: EntityMap::new(),
+            ebbs: SecondaryMap::new(),
+            insts: SecondaryMap::new(),
             first_ebb: None,
             last_ebb: None,
         }
diff --git a/lib/codegen/src/ir/mod.rs b/lib/codegen/src/ir/mod.rs
index 5421911886..a9c035703e 100644
--- a/lib/codegen/src/ir/mod.rs
+++ b/lib/codegen/src/ir/mod.rs
@@ -47,20 +47,20 @@ pub use ir::types::Type;
 pub use ir::valueloc::{ArgumentLoc, ValueLoc};
 
 use binemit;
-use entity::{EntityMap, PrimaryMap};
+use entity::{PrimaryMap, SecondaryMap};
 use isa;
 
 /// Map of value locations.
-pub type ValueLocations = EntityMap<Value, ValueLoc>;
+pub type ValueLocations = SecondaryMap<Value, ValueLoc>;
 
 /// Map of jump tables.
 pub type JumpTables = PrimaryMap<JumpTable, JumpTableData>;
 
 /// Map of instruction encodings.
-pub type InstEncodings = EntityMap<Inst, isa::Encoding>;
+pub type InstEncodings = SecondaryMap<Inst, isa::Encoding>;
 
 /// Code offsets for EBBs.
-pub type EbbOffsets = EntityMap<Ebb, binemit::CodeOffset>;
+pub type EbbOffsets = SecondaryMap<Ebb, binemit::CodeOffset>;
 
 /// Source locations for instructions.
-pub type SourceLocs = EntityMap<Inst, SourceLoc>;
+pub type SourceLocs = SecondaryMap<Inst, SourceLoc>;
diff --git a/lib/codegen/src/loop_analysis.rs b/lib/codegen/src/loop_analysis.rs
index fc1591b0cf..ded382f3f7 100644
--- a/lib/codegen/src/loop_analysis.rs
+++ b/lib/codegen/src/loop_analysis.rs
@@ -2,7 +2,7 @@
 //! and parent in the loop tree.
 
 use dominator_tree::DominatorTree;
-use entity::EntityMap;
+use entity::SecondaryMap;
 use entity::{Keys, PrimaryMap};
 use flowgraph::{BasicBlock, ControlFlowGraph};
 use ir::{Ebb, Function, Layout};
@@ -21,7 +21,7 @@ entity_impl!(Loop, "loop");
 /// its eventual parent in the loop tree and all the EBB belonging to the loop.
 pub struct LoopAnalysis {
     loops: PrimaryMap<Loop, LoopData>,
-    ebb_loop_map: EntityMap<Ebb, PackedOption<Loop>>,
+    ebb_loop_map: SecondaryMap<Ebb, PackedOption<Loop>>,
     valid: bool,
 }
 
@@ -48,7 +48,7 @@ impl LoopAnalysis {
         Self {
             valid: false,
             loops: PrimaryMap::new(),
-            ebb_loop_map: EntityMap::new(),
+            ebb_loop_map: SecondaryMap::new(),
         }
     }
 
diff --git a/lib/codegen/src/print_errors.rs b/lib/codegen/src/print_errors.rs
index db557c865e..217d09f902 100644
--- a/lib/codegen/src/print_errors.rs
+++ b/lib/codegen/src/print_errors.rs
@@ -1,6 +1,6 @@
 //! Utility routines for pretty-printing error messages.
 
-use entity::EntityMap;
+use entity::SecondaryMap;
 use ir;
 use ir::entities::{AnyEntity, Inst, Value};
 use ir::function::Function;
@@ -40,7 +40,7 @@ impl<'a> FuncWriter for PrettyVerifierError<'a> {
         &mut self,
         w: &mut Write,
         func: &Function,
-        aliases: &EntityMap<Value, Vec<Value>>,
+        aliases: &SecondaryMap<Value, Vec<Value>>,
         isa: Option<&TargetIsa>,
         inst: Inst,
         indent: usize,
@@ -63,7 +63,7 @@ impl<'a> FuncWriter for PrettyVerifierError<'a> {
 fn pretty_instruction_error(
     w: &mut Write,
     func: &Function,
-    aliases: &EntityMap<Value, Vec<Value>>,
+    aliases: &SecondaryMap<Value, Vec<Value>>,
     isa: Option<&TargetIsa>,
     cur_inst: Inst,
     indent: usize,
diff --git a/lib/codegen/src/regalloc/virtregs.rs b/lib/codegen/src/regalloc/virtregs.rs
index 0e4bcdf5d0..7d2b87153b 100644
--- a/lib/codegen/src/regalloc/virtregs.rs
+++ b/lib/codegen/src/regalloc/virtregs.rs
@@ -15,7 +15,7 @@ use dbg::DisplayList;
 use dominator_tree::DominatorTreePreorder;
 use entity::EntityRef;
 use entity::{EntityList, ListPool};
-use entity::{EntityMap, Keys, PrimaryMap};
+use entity::{Keys, PrimaryMap, SecondaryMap};
 use ir::{Function, Value};
 use packed_option::PackedOption;
 use ref_slice::ref_slice;
@@ -45,10 +45,10 @@ pub struct VirtRegs {
     unused_vregs: Vec<VirtReg>,
 
     /// Each value belongs to at most one virtual register.
-    value_vregs: EntityMap<Value, PackedOption<VirtReg>>,
+    value_vregs: SecondaryMap<Value, PackedOption<VirtReg>>,
 
     /// Table used during the union-find phase while `vregs` is empty.
-    union_find: EntityMap<Value, i32>,
+    union_find: SecondaryMap<Value, i32>,
 
     /// Values that have been activated in the `union_find` table, but not yet added to any virtual
     /// registers by the `finish_union_find()` function.
@@ -62,8 +62,8 @@ impl VirtRegs {
             pool: ListPool::new(),
             vregs: PrimaryMap::new(),
             unused_vregs: Vec::new(),
-            value_vregs: EntityMap::new(),
-            union_find: EntityMap::new(),
+            value_vregs: SecondaryMap::new(),
+            union_find: SecondaryMap::new(),
             pending_values: Vec::new(),
         }
     }
diff --git a/lib/codegen/src/verifier/flags.rs b/lib/codegen/src/verifier/flags.rs
index d3fda7555f..cf9c924244 100644
--- a/lib/codegen/src/verifier/flags.rs
+++ b/lib/codegen/src/verifier/flags.rs
@@ -1,6 +1,6 @@
 //! Verify CPU flags values.
 
-use entity::{EntityMap, SparseSet};
+use entity::{SecondaryMap, SparseSet};
 use flowgraph::{BasicBlock, ControlFlowGraph};
 use ir;
 use ir::instructions::BranchInfo;
@@ -32,7 +32,7 @@ pub fn verify_flags(
         func,
         cfg,
         encinfo: isa.map(|isa| isa.encoding_info()),
-        livein: EntityMap::new(),
+        livein: SecondaryMap::new(),
     };
     verifier.check(errors)
 }
@@ -43,7 +43,7 @@ struct FlagsVerifier<'a> {
     encinfo: Option<isa::EncInfo>,
 
     /// The single live-in flags value (if any) for each EBB.
-    livein: EntityMap<ir::Ebb, PackedOption<ir::Value>>,
+    livein: SecondaryMap<ir::Ebb, PackedOption<ir::Value>>,
 }
 
 impl<'a> FlagsVerifier<'a> {
diff --git a/lib/codegen/src/write.rs b/lib/codegen/src/write.rs
index 0c3b7cbae9..743540bf67 100644
--- a/lib/codegen/src/write.rs
+++ b/lib/codegen/src/write.rs
@@ -3,7 +3,7 @@
 //! The `write` module provides the `write_function` function which converts an IR `Function` to an
 //! equivalent textual form. This textual form can be read back by the `cranelift-reader` crate.
 
-use entity::EntityMap;
+use entity::SecondaryMap;
 use ir::entities::AnyEntity;
 use ir::{DataFlowGraph, Ebb, Function, Inst, SigRef, Type, Value, ValueDef};
 use isa::{RegInfo, TargetIsa};
@@ -19,7 +19,7 @@ pub trait FuncWriter {
         &mut self,
         w: &mut Write,
         func: &Function,
-        aliases: &EntityMap<Value, Vec<Value>>,
+        aliases: &SecondaryMap<Value, Vec<Value>>,
         isa: Option<&TargetIsa>,
         inst: Inst,
         ident: usize,
@@ -101,7 +101,7 @@ impl FuncWriter for PlainWriter {
         &mut self,
         w: &mut Write,
         func: &Function,
-        aliases: &EntityMap<Value, Vec<Value>>,
+        aliases: &SecondaryMap<Value, Vec<Value>>,
         isa: Option<&TargetIsa>,
         inst: Inst,
         indent: usize,
@@ -117,8 +117,8 @@ pub fn write_function(w: &mut Write, func: &Function, isa: Option<&TargetIsa>) -
 }
 
 /// Create a reverse-alias map from a value to all aliases having that value as a direct target
-fn alias_map(func: &Function) -> EntityMap<Value, Vec<Value>> {
-    let mut aliases = EntityMap::<_, Vec<_>>::new();
+fn alias_map(func: &Function) -> SecondaryMap<Value, Vec<Value>> {
+    let mut aliases = SecondaryMap::<_, Vec<_>>::new();
     for v in func.dfg.values() {
         // VADFS returns the immediate target of an alias
         if let Some(k) = func.dfg.value_alias_dest_for_serialization(v) {
@@ -216,7 +216,7 @@ fn decorate_ebb<FW: FuncWriter>(
     func_w: &mut FW,
     w: &mut Write,
     func: &Function,
-    aliases: &EntityMap<Value, Vec<Value>>,
+    aliases: &SecondaryMap<Value, Vec<Value>>,
     isa: Option<&TargetIsa>,
     ebb: Ebb,
 ) -> fmt::Result {
@@ -279,7 +279,7 @@ fn type_suffix(func: &Function, inst: Inst) -> Option<Type> {
 /// Write out any aliases to the given target, including indirect aliases
 fn write_value_aliases(
     w: &mut Write,
-    aliases: &EntityMap<Value, Vec<Value>>,
+    aliases: &SecondaryMap<Value, Vec<Value>>,
     target: Value,
     indent: usize,
 ) -> fmt::Result {
@@ -293,7 +293,7 @@ fn write_value_aliases(
 fn write_instruction(
     w: &mut Write,
     func: &Function,
-    aliases: &EntityMap<Value, Vec<Value>>,
+    aliases: &SecondaryMap<Value, Vec<Value>>,
     isa: Option<&TargetIsa>,
     inst: Inst,
     indent: usize,
diff --git a/lib/entity/README.md b/lib/entity/README.md
index 2b9ff7e042..f840b142e6 100644
--- a/lib/entity/README.md
+++ b/lib/entity/README.md
@@ -17,11 +17,11 @@ easy to declare new unique types for use as keys. Any attempt to use a key in
 a map it's not intended for is diagnosed with a type error.
 
 Another is that this crate has two core map types, `PrimaryMap` and
-`EntityMap`, which serve complementary purposes. A `PrimaryMap` creates its
-own keys when elements are inserted, while an `EntityMap` reuses the keys
+`SecondaryMap`, which serve complementary purposes. A `PrimaryMap` creates its
+own keys when elements are inserted, while an `SecondaryMap` reuses the keys
 values of a `PrimaryMap`, conceptually storing additional data in the same
-index space. `EntityMap`'s values must implement `Default` and all elements
-in an `EntityMap` initially have the value of `default()`.
+index space. `SecondaryMap`'s values must implement `Default` and all elements
+in an `SecondaryMap` initially have the value of `default()`.
 
 A common way to implement `Default` is to wrap a type in `Option`, however
 this crate also provides the `PackedOption` utility which can use less memory
@@ -30,9 +30,9 @@ in some cases.
 Additional utilities provided by this crate include:
  - `EntityList`, for allocating many small arrays (such as instruction operand
     lists in a compiler code generator).
- - `SparseMap`: an alternative to `EntityMap` which can use less memory
+ - `SparseMap`: an alternative to `SecondaryMap` which can use less memory
    in some situations.
- - `EntitySet`: a specialized form of `EntityMap` using a bitvector to
+ - `EntitySet`: a specialized form of `SecondaryMap` using a bitvector to
    record which entities are members of the set.
 
 [slotmap]: https://crates.io/crates/slotmap
diff --git a/lib/entity/src/lib.rs b/lib/entity/src/lib.rs
index a1d07db442..d8e4fcac18 100644
--- a/lib/entity/src/lib.rs
+++ b/lib/entity/src/lib.rs
@@ -15,7 +15,7 @@
 //!
 //! - [`PrimaryMap`](struct.PrimaryMap.html) is used to keep track of a vector of entities,
 //!   assigning a unique entity reference to each.
-//! - [`EntityMap`](struct.EntityMap.html) is used to associate secondary information to an entity.
+//! - [`SecondaryMap`](struct.SecondaryMap.html) is used to associate secondary information to an entity.
 //!   The map is implemented as a simple vector, so it does not keep track of which entities have
 //!   been inserted. Instead, any unknown entities map to the default value.
 //! - [`SparseMap`](struct.SparseMap.html) is used to associate secondary information to a small
@@ -70,7 +70,7 @@ mod std {
 pub extern crate core as __core;
 
 /// A type wrapping a small integer index should implement `EntityRef` so it can be used as the key
-/// of an `EntityMap` or `SparseMap`.
+/// of an `SecondaryMap` or `SparseMap`.
 pub trait EntityRef: Copy + Eq {
     /// Create a new entity reference from a small integer.
     /// This should crash if the requested index is not representable.
@@ -135,7 +135,7 @@ mod sparse;
 pub use self::iter::{Iter, IterMut};
 pub use self::keys::Keys;
 pub use self::list::{EntityList, ListPool};
-pub use self::map::EntityMap;
+pub use self::map::SecondaryMap;
 pub use self::primary::PrimaryMap;
 pub use self::set::EntitySet;
 pub use self::sparse::{SparseMap, SparseMapValue, SparseSet};
diff --git a/lib/entity/src/map.rs b/lib/entity/src/map.rs
index 285e61e4c6..87a478e570 100644
--- a/lib/entity/src/map.rs
+++ b/lib/entity/src/map.rs
@@ -8,14 +8,14 @@ use {EntityRef, Iter, IterMut, Keys};
 
 /// A mapping `K -> V` for densely indexed entity references.
 ///
-/// The `EntityMap` data structure uses the dense index space to implement a map with a vector.
-/// Unlike `PrimaryMap`, an `EntityMap` can't be used to allocate entity references. It is used to
+/// The `SecondaryMap` data structure uses the dense index space to implement a map with a vector.
+/// Unlike `PrimaryMap`, an `SecondaryMap` can't be used to allocate entity references. It is used to
 /// associate secondary information with entities.
 ///
 /// The map does not track if an entry for a key has been inserted or not. Instead it behaves as if
 /// all keys have a default entry from the beginning.
 #[derive(Debug, Clone)]
-pub struct EntityMap<K, V>
+pub struct SecondaryMap<K, V>
 where
     K: EntityRef,
     V: Clone,
@@ -25,8 +25,8 @@ where
     unused: PhantomData<K>,
 }
 
-/// Shared `EntityMap` implementation for all value types.
-impl<K, V> EntityMap<K, V>
+/// Shared `SecondaryMap` implementation for all value types.
+impl<K, V> SecondaryMap<K, V>
 where
     K: EntityRef,
     V: Clone,
@@ -100,10 +100,10 @@ where
     }
 }
 
-/// Immutable indexing into an `EntityMap`.
+/// Immutable indexing into an `SecondaryMap`.
 ///
 /// All keys are permitted. Untouched entries have the default value.
-impl<K, V> Index<K> for EntityMap<K, V>
+impl<K, V> Index<K> for SecondaryMap<K, V>
 where
     K: EntityRef,
     V: Clone,
@@ -115,10 +115,10 @@ where
     }
 }
 
-/// Mutable indexing into an `EntityMap`.
+/// Mutable indexing into an `SecondaryMap`.
 ///
 /// The map grows as needed to accommodate new keys.
-impl<K, V> IndexMut<K> for EntityMap<K, V>
+impl<K, V> IndexMut<K> for SecondaryMap<K, V>
 where
     K: EntityRef,
     V: Clone,
@@ -154,7 +154,7 @@ mod tests {
         let r0 = E(0);
         let r1 = E(1);
         let r2 = E(2);
-        let mut m = EntityMap::new();
+        let mut m = SecondaryMap::new();
 
         let v: Vec<E> = m.keys().collect();
         assert_eq!(v, []);
diff --git a/lib/entity/src/set.rs b/lib/entity/src/set.rs
index 7644db49ad..4f7b631c93 100644
--- a/lib/entity/src/set.rs
+++ b/lib/entity/src/set.rs
@@ -7,7 +7,7 @@ use {EntityRef, Keys};
 /// A set of `K` for densely indexed entity references.
 ///
 /// The `EntitySet` data structure uses the dense index space to implement a set with a bitvector.
-/// Like `EntityMap`, an `EntitySet` is used to associate secondary information with entities.
+/// Like `SecondaryMap`, an `EntitySet` is used to associate secondary information with entities.
 #[derive(Debug, Clone)]
 pub struct EntitySet<K>
 where
diff --git a/lib/entity/src/sparse.rs b/lib/entity/src/sparse.rs
index 28cbd80ad8..1a6de3e39d 100644
--- a/lib/entity/src/sparse.rs
+++ b/lib/entity/src/sparse.rs
@@ -11,7 +11,7 @@ use std::mem;
 use std::slice;
 use std::u32;
 use std::vec::Vec;
-use {EntityMap, EntityRef};
+use {EntityRef, SecondaryMap};
 
 /// Trait for extracting keys from values stored in a `SparseMap`.
 ///
@@ -27,16 +27,16 @@ pub trait SparseMapValue<K> {
 ///
 /// A `SparseMap<K, V>` map provides:
 ///
-/// - Memory usage equivalent to `EntityMap<K, u32>` + `Vec<V>`, so much smaller than
-///   `EntityMap<K, V>` for sparse mappings of larger `V` types.
-/// - Constant time lookup, slightly slower than `EntityMap`.
+/// - Memory usage equivalent to `SecondaryMap<K, u32>` + `Vec<V>`, so much smaller than
+///   `SecondaryMap<K, V>` for sparse mappings of larger `V` types.
+/// - Constant time lookup, slightly slower than `SecondaryMap`.
 /// - A very fast, constant time `clear()` operation.
 /// - Fast insert and erase operations.
 /// - Stable iteration that is as fast as a `Vec<V>`.
 ///
-/// # Compared to `EntityMap`
+/// # Compared to `SecondaryMap`
 ///
-/// When should we use a `SparseMap` instead of a secondary `EntityMap`? First of all, `SparseMap`
+/// When should we use a `SparseMap` instead of a secondary `SecondaryMap`? First of all, `SparseMap`
 /// does not provide the functionality of a `PrimaryMap` which can allocate and assign entity
 /// references to objects as they are pushed onto the map. It is only the secondary entity maps
 /// that can be replaced with a `SparseMap`.
@@ -44,10 +44,10 @@ pub trait SparseMapValue<K> {
 /// - A secondary entity map assigns a default mapping to all keys. It doesn't distinguish between
 ///   an unmapped key and one that maps to the default value. `SparseMap` does not require
 ///   `Default` values, and it tracks accurately if a key has been mapped or not.
-/// - Iterating over the contents of an `EntityMap` is linear in the size of the *key space*, while
+/// - Iterating over the contents of an `SecondaryMap` is linear in the size of the *key space*, while
 ///   iterating over a `SparseMap` is linear in the number of elements in the mapping. This is an
 ///   advantage precisely when the mapping is sparse.
-/// - `SparseMap::clear()` is constant time and super-fast. `EntityMap::clear()` is linear in the
+/// - `SparseMap::clear()` is constant time and super-fast. `SecondaryMap::clear()` is linear in the
 ///   size of the key space. (Or, rather the required `resize()` call following the `clear()` is).
 /// - `SparseMap` requires the values to implement `SparseMapValue<K>` which means that they must
 ///   contain their own key.
@@ -56,7 +56,7 @@ where
     K: EntityRef,
     V: SparseMapValue<K>,
 {
-    sparse: EntityMap<K, u32>,
+    sparse: SecondaryMap<K, u32>,
     dense: Vec<V>,
 }
 
@@ -68,7 +68,7 @@ where
     /// Create a new empty mapping.
     pub fn new() -> Self {
         Self {
-            sparse: EntityMap::new(),
+            sparse: SecondaryMap::new(),
             dense: Vec::new(),
         }
     }
diff --git a/lib/frontend/src/frontend.rs b/lib/frontend/src/frontend.rs
index d32e1892e7..98cdc1c753 100644
--- a/lib/frontend/src/frontend.rs
+++ b/lib/frontend/src/frontend.rs
@@ -1,6 +1,6 @@
 //! A frontend for building Cranelift IR from other languages.
 use cranelift_codegen::cursor::{Cursor, FuncCursor};
-use cranelift_codegen::entity::{EntityMap, EntitySet};
+use cranelift_codegen::entity::{EntitySet, SecondaryMap};
 use cranelift_codegen::ir;
 use cranelift_codegen::ir::function::DisplayFunction;
 use cranelift_codegen::ir::{
@@ -24,8 +24,8 @@ use variable::Variable;
 /// use here, `variable::Variable` can be used.
 pub struct FunctionBuilderContext {
     ssa: SSABuilder,
-    ebbs: EntityMap<Ebb, EbbData>,
-    types: EntityMap<Variable, Type>,
+    ebbs: SecondaryMap<Ebb, EbbData>,
+    types: SecondaryMap<Variable, Type>,
 }
 
 /// Temporary object used to build a single Cranelift IR `Function`.
@@ -79,8 +79,8 @@ impl FunctionBuilderContext {
     pub fn new() -> Self {
         Self {
             ssa: SSABuilder::new(),
-            ebbs: EntityMap::new(),
-            types: EntityMap::new(),
+            ebbs: SecondaryMap::new(),
+            types: SecondaryMap::new(),
         }
     }
 
diff --git a/lib/frontend/src/ssa.rs b/lib/frontend/src/ssa.rs
index 3474b5104e..2cb6839b76 100644
--- a/lib/frontend/src/ssa.rs
+++ b/lib/frontend/src/ssa.rs
@@ -6,7 +6,7 @@
 //! Lecture Notes in Computer Science, vol 7791. Springer, Berlin, Heidelberg
 
 use cranelift_codegen::cursor::{Cursor, FuncCursor};
-use cranelift_codegen::entity::{EntityMap, EntityRef, PrimaryMap};
+use cranelift_codegen::entity::{EntityRef, PrimaryMap, SecondaryMap};
 use cranelift_codegen::ir::immediates::{Ieee32, Ieee64};
 use cranelift_codegen::ir::instructions::BranchInfo;
 use cranelift_codegen::ir::types::{F32, F64};
@@ -36,13 +36,13 @@ use Variable;
 pub struct SSABuilder {
     // Records for every variable and for every relevant block, the last definition of
     // the variable in the block.
-    // TODO: Consider a sparse representation rather than EntityMap-of-EntityMap.
-    variables: EntityMap<Variable, EntityMap<Block, PackedOption<Value>>>,
+    // TODO: Consider a sparse representation rather than SecondaryMap-of-SecondaryMap.
+    variables: SecondaryMap<Variable, SecondaryMap<Block, PackedOption<Value>>>,
     // Records the position of the basic blocks and the list of values used but not defined in the
     // block.
     blocks: PrimaryMap<Block, BlockData>,
     // Records the basic blocks at the beginning of the `Ebb`s.
-    ebb_headers: EntityMap<Ebb, PackedOption<Block>>,
+    ebb_headers: SecondaryMap<Ebb, PackedOption<Block>>,
 
     // Call and result stacks for use in the `use_var`/`predecessors_lookup` state machine.
     calls: Vec<Call>,
@@ -158,9 +158,9 @@ impl SSABuilder {
     /// Allocate a new blank SSA builder struct. Use the API function to interact with the struct.
     pub fn new() -> Self {
         Self {
-            variables: EntityMap::with_default(EntityMap::new()),
+            variables: SecondaryMap::with_default(SecondaryMap::new()),
             blocks: PrimaryMap::new(),
-            ebb_headers: EntityMap::new(),
+            ebb_headers: SecondaryMap::new(),
             calls: Vec::new(),
             results: Vec::new(),
             side_effects: SideEffects::new(),