diff --git a/Cargo.lock b/Cargo.lock
index 6a2815313ac7..aad4a2bc11d6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -250,6 +250,18 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "bstr"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a40b47ad93e1a5404e6c18dec46b628214fee441c70f4ab5d6942142cc268a3d"
+dependencies = [
+ "lazy_static",
+ "memchr",
+ "regex-automata",
+ "serde",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.6.1"
@@ -276,7 +288,7 @@ checksum = "ff3a1e32332db9ad29d6da34693ce9a7ac26a9edf96abb5c1788d193410031ab"
 dependencies = [
  "cap-primitives",
  "cap-std",
- "rustc_version",
+ "rustc_version 0.3.3",
  "unsafe-io",
  "winapi",
 ]
@@ -294,7 +306,7 @@ dependencies = [
  "maybe-owned",
  "once_cell",
  "posish",
- "rustc_version",
+ "rustc_version 0.3.3",
  "unsafe-io",
  "winapi",
  "winapi-util",
@@ -318,7 +330,7 @@ checksum = "7019d48ea53c5f378e0fdab0fe5f627fc00e76d65e75dffd6fb1cbc0c9b382ee"
 dependencies = [
  "cap-primitives",
  "posish",
- "rustc_version",
+ "rustc_version 0.3.3",
  "unsafe-io",
 ]
 
@@ -365,6 +377,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "cast"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc38c385bfd7e444464011bb24820f40dd1c76bcdfa1b78611cb7c2e5cafab75"
+dependencies = [
+ "rustc_version 0.2.3",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.67"
@@ -542,6 +563,7 @@ dependencies = [
  "cranelift-codegen-meta",
  "cranelift-codegen-shared",
  "cranelift-entity",
+ "criterion",
  "gimli",
  "hashbrown",
  "log",
@@ -748,7 +770,7 @@ dependencies = [
  "cranelift-entity",
  "cranelift-frontend",
  "hashbrown",
- "itertools",
+ "itertools 0.10.0",
  "log",
  "serde",
  "smallvec",
@@ -767,6 +789,42 @@ dependencies = [
  "cfg-if 1.0.0",
 ]
 
+[[package]]
+name = "criterion"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab327ed7354547cc2ef43cbe20ef68b988e70b4b593cbd66a2a61733123a3d23"
+dependencies = [
+ "atty",
+ "cast",
+ "clap",
+ "criterion-plot",
+ "csv",
+ "itertools 0.10.0",
+ "lazy_static",
+ "num-traits",
+ "oorandom",
+ "plotters",
+ "rayon",
+ "regex",
+ "serde",
+ "serde_cbor",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e022feadec601fba1649cfa83586381a4ad31c6bf3a9ab7d408118b05dd9889d"
+dependencies = [
+ "cast",
+ "itertools 0.9.0",
+]
+
 [[package]]
 name = "crossbeam-channel"
 version = "0.5.0"
@@ -822,6 +880,28 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "csv"
+version = "1.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22813a6dc45b335f9bade10bf7271dc477e81113e89eb251a0bc2a8a81c536e1"
+dependencies = [
+ "bstr",
+ "csv-core",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "csv-core"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b2466559f260f48ad25fe6317b3c8dac77b5bdb5763ac7d9d6103530663bc90"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "ctr"
 version = "0.6.0"
@@ -1252,6 +1332,12 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "half"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62aca2aba2d62b4a7f5b33f3712cb1b0692779a56fb510499d5c0aa594daeaf3"
+
 [[package]]
 name = "hashbrown"
 version = "0.9.1"
@@ -1369,6 +1455,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "284f18f85651fe11e8a991b2adb42cb078325c996ed026d994719efcfca1d54b"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools"
 version = "0.10.0"
@@ -1402,6 +1497,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "js-sys"
+version = "0.3.51"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "83bdfbace3a0e81a4253f73b49e960b053e396a11012cbd49b9b74d6a2b67062"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "k256"
 version = "0.7.2"
@@ -1478,7 +1582,7 @@ dependencies = [
  "dynasm",
  "dynasmrt",
  "iter-enum",
- "itertools",
+ "itertools 0.10.0",
  "lazy_static",
  "memoffset",
  "more-asserts",
@@ -1747,6 +1851,12 @@ version = "1.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af8b08b04175473088b46763e51ee54da5f9a164bc162f615b91bc179dbf15a3"
 
+[[package]]
+name = "oorandom"
+version = "11.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
+
 [[package]]
 name = "opaque-debug"
 version = "0.3.0"
@@ -1986,6 +2096,34 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "plotters"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45ca0ae5f169d0917a7c7f5a9c1a3d3d9598f18f529dd2b8373ed988efea307a"
+dependencies = [
+ "num-traits",
+ "plotters-backend",
+ "plotters-svg",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "plotters-backend"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b07fffcddc1cb3a1de753caa4e4df03b79922ba43cf882acc1bdd7e8df9f4590"
+
+[[package]]
+name = "plotters-svg"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b38a02e23bd9604b842a812063aec4ef702b57989c37b655254bb61c471ad211"
+dependencies = [
+ "plotters-backend",
+]
+
 [[package]]
 name = "poly1305"
 version = "0.6.2"
@@ -2420,13 +2558,22 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+dependencies = [
+ "semver 0.9.0",
+]
+
 [[package]]
 name = "rustc_version"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0dfe2087c51c460008730de8b57e6a320782fbfb312e1f4d520e6c6fae155ee"
 dependencies = [
- "semver",
+ "semver 0.11.0",
 ]
 
 [[package]]
@@ -2482,15 +2629,30 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "semver"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
+dependencies = [
+ "semver-parser 0.7.0",
+]
+
 [[package]]
 name = "semver"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f301af10236f6df4160f7c3f04eec6dbc70ace82d23326abad5edee88801c6b6"
 dependencies = [
- "semver-parser",
+ "semver-parser 0.10.2",
 ]
 
+[[package]]
+name = "semver-parser"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
+
 [[package]]
 name = "semver-parser"
 version = "0.10.2"
@@ -2509,6 +2671,16 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde_cbor"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e18acfa2f90e8b735b2836ab8d538de304cbb6729a7360729ea5a895d15a622"
+dependencies = [
+ "half",
+ "serde",
+]
+
 [[package]]
 name = "serde_derive"
 version = "1.0.123"
@@ -2696,9 +2868,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.60"
+version = "1.0.67"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c700597eca8a5a762beb35753ef6b94df201c81cca676604f547495a0d7f0081"
+checksum = "6498a9efc342871f91cc2d0d694c674368b4ceb40f62b65a7a08c3792935e702"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2728,7 +2900,7 @@ dependencies = [
  "cap-fs-ext",
  "cap-std",
  "posish",
- "rustc_version",
+ "rustc_version 0.3.3",
  "unsafe-io",
  "winapi",
  "winx",
@@ -2840,6 +3012,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "tokio"
 version = "1.5.0"
@@ -3022,7 +3204,7 @@ version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fe39acfe60d3754452ea6881613c3240100b23ffd94a627c138863f8cd314b1b"
 dependencies = [
- "rustc_version",
+ "rustc_version 0.3.3",
  "winapi",
 ]
 
@@ -3200,6 +3382,60 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d54ee1d4ed486f78874278e63e4069fc1ab9f6a18ca492076ffb90c5eb2997fd"
+dependencies = [
+ "cfg-if 1.0.0",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b33f6a0694ccfea53d94db8b2ed1c3a8a4c86dd936b13b9f0a15ec4a451b900"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "088169ca61430fe1e58b8096c24975251700e7b1f6fd91cc9d59b04fb9b18bd4"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be2241542ff3d9f241f5e2cb6dd09b37efe786df8851c54957683a49f0987a97"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.74"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7cff876b8f18eed75a66cf49b65e7f967cb354a7aa16003fb55dbfd25b44b4f"
+
 [[package]]
 name = "wasm-encoder"
 version = "0.4.1"
@@ -3700,6 +3936,16 @@ dependencies = [
  "wast 35.0.2",
 ]
 
+[[package]]
+name = "web-sys"
+version = "0.3.51"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e828417b379f3df7111d3a2a9e5753706cae29c41f7c4029ee9fd77f3e09e582"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "wiggle"
 version = "0.26.0"
diff --git a/cranelift/codegen/Cargo.toml b/cranelift/codegen/Cargo.toml
index 5e21f11a19f2..2f35b5fe4b78 100644
--- a/cranelift/codegen/Cargo.toml
+++ b/cranelift/codegen/Cargo.toml
@@ -34,6 +34,9 @@ wast = { version = "35.0.0", optional = true }
 # machine code. Integration tests that need external dependencies can be
 # accomodated in `tests`.
 
+[dev-dependencies]
+criterion = "0.3"
+
 [build-dependencies]
 cranelift-codegen-meta = { path = "meta", version = "0.73.0" }
 
@@ -103,3 +106,7 @@ souper-harvest = ["souper-ir", "souper-ir/stringify"]
 
 [badges]
 maintenance = { status = "experimental" }
+
+[[bench]]
+name = "x64-evex-encoding"
+harness = false
diff --git a/cranelift/codegen/benches/x64-evex-encoding.rs b/cranelift/codegen/benches/x64-evex-encoding.rs
new file mode 100644
index 000000000000..e5c1434181cf
--- /dev/null
+++ b/cranelift/codegen/benches/x64-evex-encoding.rs
@@ -0,0 +1,138 @@
+//! Measure instruction encoding latency using various approaches; the
+//! benchmarking is feature-gated on `x86` since it only measures the encoding
+//! mechanism of that backend.
+
+#[cfg(feature = "x86")]
+mod x86 {
+    use cranelift_codegen::isa::x64::encoding::{
+        evex::{EvexContext, EvexInstruction, EvexMasking, EvexVectorLength, Register},
+        rex::OpcodeMap,
+        rex::{encode_modrm, LegacyPrefixes},
+        ByteSink,
+    };
+    use cranelift_codegen_shared::isa::x86::EncodingBits;
+    use criterion::{criterion_group, Criterion};
+
+    // Define the benchmarks.
+    fn x64_evex_encoding_benchmarks(c: &mut Criterion) {
+        let mut group = c.benchmark_group("x64 EVEX encoding");
+        let rax = Register::from(0);
+        let rdx = Register::from(2);
+
+        group.bench_function("EvexInstruction (builder pattern)", |b| {
+            let mut sink = vec![];
+            b.iter(|| {
+                sink.clear();
+                EvexInstruction::new()
+                    .prefix(LegacyPrefixes::_66)
+                    .map(OpcodeMap::_0F38)
+                    .w(true)
+                    .opcode(0x1F)
+                    .reg(rax)
+                    .rm(rdx)
+                    .length(EvexVectorLength::V128)
+                    .encode(&mut sink);
+            });
+        });
+
+        group.bench_function("encode_evex (function pattern)", |b| {
+            let mut sink = vec![];
+            let bits = EncodingBits::new(&[0x66, 0x0f, 0x38, 0x1f], 0, 1);
+            let vvvvv = Register::from(0);
+            b.iter(|| {
+                sink.clear();
+                encode_evex(
+                    bits,
+                    rax,
+                    vvvvv,
+                    rdx,
+                    EvexContext::Other {
+                        length: EvexVectorLength::V128,
+                    },
+                    EvexMasking::default(),
+                    &mut sink,
+                );
+            })
+        });
+    }
+    criterion_group!(benches, x64_evex_encoding_benchmarks);
+
+    /// Using an inner module to feature-gate the benchmarks means that we must
+    /// manually specify how to run the benchmarks (see `criterion_main!`).
+    pub fn run_benchmarks() {
+        criterion::__warn_about_html_reports_feature();
+        criterion::__warn_about_cargo_bench_support_feature();
+        benches();
+        Criterion::default().configure_from_args().final_summary();
+    }
+
+    /// From the legacy x86 backend: a mechanism for encoding an EVEX
+    /// instruction, including the prefixes, the instruction opcode, and the
+    /// ModRM byte. This EVEX encoding function only encodes the `reg` (operand
+    /// 1), `vvvv` (operand 2), `rm` (operand 3) form; other forms are possible
+    /// (see section 2.6.2, Intel Software Development Manual, volume 2A),
+    /// requiring refactoring of this function or separate functions for each
+    /// form (e.g. as for the REX prefix).
+    #[inline(always)]
+    pub fn encode_evex<CS: ByteSink + ?Sized>(
+        enc: EncodingBits,
+        reg: Register,
+        vvvvv: Register,
+        rm: Register,
+        context: EvexContext,
+        masking: EvexMasking,
+        sink: &mut CS,
+    ) {
+        let reg: u8 = reg.into();
+        let rm: u8 = rm.into();
+        let vvvvv: u8 = vvvvv.into();
+
+        // EVEX prefix.
+        sink.put1(0x62);
+
+        debug_assert!(enc.mm() < 0b100);
+        let mut p0 = enc.mm() & 0b11;
+        p0 |= evex2(rm, reg) << 4; // bits 3:2 are always unset
+        sink.put1(p0);
+
+        let mut p1 = enc.pp() | 0b100; // bit 2 is always set
+        p1 |= (!(vvvvv) & 0b1111) << 3;
+        p1 |= (enc.rex_w() & 0b1) << 7;
+        sink.put1(p1);
+
+        let mut p2 = masking.aaa_bits();
+        p2 |= (!(vvvvv >> 4) & 0b1) << 3;
+        p2 |= context.bits() << 4;
+        p2 |= masking.z_bit() << 7;
+        sink.put1(p2);
+
+        // Opcode.
+        sink.put1(enc.opcode_byte());
+
+        // ModR/M byte.
+        sink.put1(encode_modrm(3, reg & 7, rm & 7))
+    }
+
+    /// From the legacy x86 backend: encode the RXBR' bits of the EVEX P0 byte.
+    /// For an explanation of these bits, see section 2.6.1 in the Intel
+    /// Software Development Manual, volume 2A. These bits can be used by
+    /// different addressing modes (see section 2.6.2), requiring different
+    /// `vex*` functions than this one.
+    fn evex2(rm: u8, reg: u8) -> u8 {
+        let b = !(rm >> 3) & 1;
+        let x = !(rm >> 4) & 1;
+        let r = !(reg >> 3) & 1;
+        let r_ = !(reg >> 4) & 1;
+        0x00 | r_ | (b << 1) | (x << 2) | (r << 3)
+    }
+}
+
+fn main() {
+    #[cfg(feature = "x86")]
+    x86::run_benchmarks();
+
+    #[cfg(not(feature = "x86"))]
+    println!(
+        "Unable to run the x64-evex-encoding benchmark; the `x86` feature must be enabled in Cargo.",
+    );
+}
diff --git a/cranelift/codegen/src/isa/mod.rs b/cranelift/codegen/src/isa/mod.rs
index f2252e256226..481c0c8de310 100644
--- a/cranelift/codegen/src/isa/mod.rs
+++ b/cranelift/codegen/src/isa/mod.rs
@@ -81,8 +81,10 @@ mod riscv;
 #[cfg(feature = "x86")]
 mod x86;
 
+// This module is made public here for benchmarking purposes. No guarantees are
+// made regarding API stability.
 #[cfg(feature = "x86")]
-mod x64;
+pub mod x64;
 
 #[cfg(feature = "arm32")]
 mod arm32;
diff --git a/cranelift/codegen/src/isa/x64/inst/encoding/evex.rs b/cranelift/codegen/src/isa/x64/encoding/evex.rs
similarity index 96%
rename from cranelift/codegen/src/isa/x64/inst/encoding/evex.rs
rename to cranelift/codegen/src/isa/x64/encoding/evex.rs
index 9029b9f43e08..80a3c86bda86 100644
--- a/cranelift/codegen/src/isa/x64/inst/encoding/evex.rs
+++ b/cranelift/codegen/src/isa/x64/encoding/evex.rs
@@ -208,6 +208,8 @@ impl EvexInstruction {
     }
 }
 
+/// Describe the register index to use. This wrapper is a type-safe way to pass
+/// around the registers defined in `inst/regs.rs`.
 #[derive(Copy, Clone, Default)]
 pub struct Register(u8);
 impl From<u8> for Register {
@@ -216,13 +218,18 @@ impl From<u8> for Register {
         Self(reg)
     }
 }
+impl Into<u8> for Register {
+    fn into(self) -> u8 {
+        self.0
+    }
+}
 
 /// Defines the EVEX context for the `L'`, `L`, and `b` bits (bits 6:4 of EVEX P2 byte). Table 2-36 in
 /// section 2.6.10 (Intel Software Development Manual, volume 2A) describes how these bits can be
 /// used together for certain classes of instructions; i.e., special care should be taken to ensure
 /// that instructions use an applicable correct `EvexContext`. Table 2-39 contains cases where
 /// opcodes can result in an #UD.
-#[allow(dead_code)] // Rounding and broadcast modes are not yet used.
+#[allow(dead_code, missing_docs)] // Rounding and broadcast modes are not yet used.
 pub enum EvexContext {
     RoundingRegToRegFP {
         rc: EvexRoundingControl,
@@ -250,7 +257,7 @@ impl Default for EvexContext {
 
 impl EvexContext {
     /// Encode the `L'`, `L`, and `b` bits (bits 6:4 of EVEX P2 byte) for merging with the P2 byte.
-    fn bits(&self) -> u8 {
+    pub fn bits(&self) -> u8 {
         match self {
             Self::RoundingRegToRegFP { rc } => 0b001 | rc.bits() << 1,
             Self::NoRoundingFP { sae, length } => (*sae as u8) | length.bits() << 1,
@@ -261,7 +268,7 @@ impl EvexContext {
 }
 
 /// The EVEX format allows choosing a vector length in the `L'` and `L` bits; see `EvexContext`.
-#[allow(dead_code)] // Wider-length vectors are not yet used.
+#[allow(dead_code, missing_docs)] // Wider-length vectors are not yet used.
 pub enum EvexVectorLength {
     V128,
     V256,
@@ -287,7 +294,7 @@ impl Default for EvexVectorLength {
 }
 
 /// The EVEX format allows defining rounding control in the `L'` and `L` bits; see `EvexContext`.
-#[allow(dead_code)] // Rounding controls are not yet used.
+#[allow(dead_code, missing_docs)] // Rounding controls are not yet used.
 pub enum EvexRoundingControl {
     RNE,
     RD,
@@ -309,7 +316,7 @@ impl EvexRoundingControl {
 
 /// Defines the EVEX masking behavior; masking support is described in section 2.6.4 of the Intel
 /// Software Development Manual, volume 2A.
-#[allow(dead_code)] // Masking is not yet used.
+#[allow(dead_code, missing_docs)] // Masking is not yet used.
 pub enum EvexMasking {
     None,
     Merging { k: u8 },
@@ -324,7 +331,7 @@ impl Default for EvexMasking {
 
 impl EvexMasking {
     /// Encode the `z` bit for merging with the P2 byte.
-    fn z_bit(&self) -> u8 {
+    pub fn z_bit(&self) -> u8 {
         match self {
             Self::None | Self::Merging { .. } => 0,
             Self::Zeroing { .. } => 1,
@@ -332,7 +339,7 @@ impl EvexMasking {
     }
 
     /// Encode the `aaa` bits for merging with the P2 byte.
-    fn aaa_bits(&self) -> u8 {
+    pub fn aaa_bits(&self) -> u8 {
         match self {
             Self::None => 0b000,
             Self::Merging { k } | Self::Zeroing { k } => {
diff --git a/cranelift/codegen/src/isa/x64/inst/encoding/mod.rs b/cranelift/codegen/src/isa/x64/encoding/mod.rs
similarity index 87%
rename from cranelift/codegen/src/isa/x64/inst/encoding/mod.rs
rename to cranelift/codegen/src/isa/x64/encoding/mod.rs
index a269e586094f..9dd269764989 100644
--- a/cranelift/codegen/src/isa/x64/inst/encoding/mod.rs
+++ b/cranelift/codegen/src/isa/x64/encoding/mod.rs
@@ -1,3 +1,4 @@
+//! Contains the encoding machinery for the various x64 instruction formats.
 use crate::{isa::x64, machinst::MachBuffer};
 use std::vec::Vec;
 
@@ -5,6 +6,8 @@ pub mod evex;
 pub mod rex;
 pub mod vex;
 
+/// The encoding formats in this module all require a way of placing bytes into
+/// a buffer.
 pub trait ByteSink {
     /// Add 1 byte to the code section.
     fn put1(&mut self, _: u8);
diff --git a/cranelift/codegen/src/isa/x64/inst/encoding/rex.rs b/cranelift/codegen/src/isa/x64/encoding/rex.rs
similarity index 99%
rename from cranelift/codegen/src/isa/x64/inst/encoding/rex.rs
rename to cranelift/codegen/src/isa/x64/encoding/rex.rs
index 648941790e50..51016fa39e70 100644
--- a/cranelift/codegen/src/isa/x64/inst/encoding/rex.rs
+++ b/cranelift/codegen/src/isa/x64/encoding/rex.rs
@@ -28,8 +28,9 @@ pub(crate) fn low8_will_sign_extend_to_32(x: u32) -> bool {
     xs == ((xs << 24) >> 24)
 }
 
+/// Encode the ModR/M byte.
 #[inline(always)]
-pub(crate) fn encode_modrm(m0d: u8, enc_reg_g: u8, rm_e: u8) -> u8 {
+pub fn encode_modrm(m0d: u8, enc_reg_g: u8, rm_e: u8) -> u8 {
     debug_assert!(m0d < 4);
     debug_assert!(enc_reg_g < 8);
     debug_assert!(rm_e < 8);
@@ -155,6 +156,7 @@ impl From<(OperandSize, Reg)> for RexFlags {
 
 /// Allows using the same opcode byte in different "opcode maps" to allow for more instruction
 /// encodings. See appendix A in the Intel Software Developer's Manual, volume 2A, for more details.
+#[allow(missing_docs)]
 pub enum OpcodeMap {
     None,
     _0F,
diff --git a/cranelift/codegen/src/isa/x64/inst/encoding/vex.rs b/cranelift/codegen/src/isa/x64/encoding/vex.rs
similarity index 100%
rename from cranelift/codegen/src/isa/x64/inst/encoding/vex.rs
rename to cranelift/codegen/src/isa/x64/encoding/vex.rs
diff --git a/cranelift/codegen/src/isa/x64/inst/emit.rs b/cranelift/codegen/src/isa/x64/inst/emit.rs
index a35bbe0a9994..0bd74ecd8ba4 100644
--- a/cranelift/codegen/src/isa/x64/inst/emit.rs
+++ b/cranelift/codegen/src/isa/x64/inst/emit.rs
@@ -2,16 +2,16 @@ use crate::binemit::{Addend, Reloc};
 use crate::ir::immediates::{Ieee32, Ieee64};
 use crate::ir::LibCall;
 use crate::ir::TrapCode;
-use crate::isa::x64::inst::args::*;
-use crate::isa::x64::inst::*;
-use crate::machinst::{inst_common, MachBuffer, MachInstEmit, MachLabel};
-use core::convert::TryInto;
-use encoding::evex::{EvexInstruction, EvexVectorLength};
-use encoding::rex::{
+use crate::isa::x64::encoding::evex::{EvexInstruction, EvexVectorLength};
+use crate::isa::x64::encoding::rex::{
     emit_simm, emit_std_enc_enc, emit_std_enc_mem, emit_std_reg_mem, emit_std_reg_reg, int_reg_enc,
     low8_will_sign_extend_to_32, low8_will_sign_extend_to_64, reg_enc, LegacyPrefixes, OpcodeMap,
     RexFlags,
 };
+use crate::isa::x64::inst::args::*;
+use crate::isa::x64::inst::*;
+use crate::machinst::{inst_common, MachBuffer, MachInstEmit, MachLabel};
+use core::convert::TryInto;
 use log::debug;
 use regalloc::{Reg, Writable};
 
diff --git a/cranelift/codegen/src/isa/x64/inst/mod.rs b/cranelift/codegen/src/isa/x64/inst/mod.rs
index cfb0351bf38c..fe89ac4c9009 100644
--- a/cranelift/codegen/src/isa/x64/inst/mod.rs
+++ b/cranelift/codegen/src/isa/x64/inst/mod.rs
@@ -22,7 +22,6 @@ pub mod args;
 mod emit;
 #[cfg(test)]
 mod emit_tests;
-pub(crate) mod encoding;
 pub mod regs;
 pub mod unwind;
 
@@ -2856,7 +2855,7 @@ impl EmitState {
         self.stack_map = None;
     }
 
-    fn cur_srcloc(&self) -> SourceLoc {
+    pub(crate) fn cur_srcloc(&self) -> SourceLoc {
         self.cur_srcloc
     }
 }
diff --git a/cranelift/codegen/src/isa/x64/mod.rs b/cranelift/codegen/src/isa/x64/mod.rs
index c150c01f238e..6ca4a7cec4f7 100644
--- a/cranelift/codegen/src/isa/x64/mod.rs
+++ b/cranelift/codegen/src/isa/x64/mod.rs
@@ -18,6 +18,7 @@ use target_lexicon::Triple;
 use crate::isa::unwind::systemv;
 
 mod abi;
+pub mod encoding;
 mod inst;
 mod lower;
 mod settings;
diff --git a/deny.toml b/deny.toml
index 7f909d470ecd..a08d5812160e 100644
--- a/deny.toml
+++ b/deny.toml
@@ -45,4 +45,7 @@ skip = [
     { name = "wast" }, # old one pulled in by witx
     { name = "itertools" }, # 0.9 pulled in by zstd-sys
     { name = "quick-error" }, # transitive dependencies
+    { name = "rustc_version" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
+    { name = "semver" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
+    { name = "semver-parser" }, # transitive dependencies of criterion's build script (see https://github.com/japaric/cast.rs/pull/26)
 ]