diff --git a/.gitignore b/.gitignore
index c80746c73..d69413c15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,6 +34,7 @@ install/
 
 # Build artefacts
 /rust/target/
+/rust/cli/target/
 contrib/linux-kernel/linux/
 projects/
 bin/
diff --git a/programs/Makefile b/programs/Makefile
index 14f295c5b..bcd268e99 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -32,7 +32,8 @@ RUST_CLI_MANIFEST := $(RUST_CLI_DIR)/Cargo.toml
 RUST_SOURCES := $(RUST_MANIFEST) $(RUST_DIR)/Cargo.lock \
                 $(shell find $(RUST_DIR)/src -type f -name '*.rs' -print)
 RUST_CLI_SOURCES := $(RUST_CLI_MANIFEST) $(RUST_CLI_DIR)/Cargo.lock \
-                    $(RUST_CLI_DIR)/src/lib.rs $(RUST_DIR)/src/zstd_cli.rs
+                    $(RUST_CLI_DIR)/src/lib.rs $(RUST_DIR)/src/zstd_cli.rs \
+                    $(RUST_DIR)/src/timefn.rs
 
 # Keep Rust's HUF implementation in lockstep with libzstd.mk's C selection.
 # Forced modes may arrive as libzstd.mk variables or as direct -D flags in
@@ -88,7 +89,7 @@ RUST_CLI_STATICLIB := $(RUST_CLI_TARGET_DIR)/release/libzstd_cli_rs.a
 RUST_CLI_STATICLIB_32 := $(RUST_CLI_TARGET_DIR)/$(RUST_TARGET_32)/release/libzstd_cli_rs.a
 RUST_CLI_CARGO_FLAGS := --manifest-path $(RUST_CLI_MANIFEST) --release \
                         --target-dir $(RUST_CLI_TARGET_DIR) \
-                        --no-default-features --features compression,decompression
+                        --no-default-features --features cli,compression,decompression
 
 $(RUST_CLI_STATICLIB): $(RUST_CLI_SOURCES)
 	$(CARGO) build $(RUST_CLI_CARGO_FLAGS)
@@ -114,7 +115,7 @@ RUST_DECOMPRESS_CLI_TARGET_DIR := $(RUST_DIR)/target/$(RUST_DECOMPRESS_CLI_BUILD
 RUST_DECOMPRESS_CLI_STATICLIB := $(RUST_DECOMPRESS_CLI_TARGET_DIR)/release/libzstd_cli_rs.a
 RUST_DECOMPRESS_CLI_CARGO_FLAGS := --manifest-path $(RUST_CLI_MANIFEST) --release \
                                     --target-dir $(RUST_DECOMPRESS_CLI_TARGET_DIR) \
-                                    --no-default-features --features decompression
+                                    --no-default-features --features cli,decompression
 
 $(RUST_DECOMPRESS_CLI_STATICLIB): $(RUST_CLI_SOURCES)
 	$(CARGO) build $(RUST_DECOMPRESS_CLI_CARGO_FLAGS)
@@ -145,7 +146,7 @@ RUST_COMPRESS_CLI_TARGET_DIR := $(RUST_DIR)/target/$(RUST_COMPRESS_CLI_BUILD_CON
 RUST_COMPRESS_CLI_STATICLIB := $(RUST_COMPRESS_CLI_TARGET_DIR)/release/libzstd_cli_rs.a
 RUST_COMPRESS_CLI_CARGO_FLAGS := --manifest-path $(RUST_CLI_MANIFEST) --release \
                                   --target-dir $(RUST_COMPRESS_CLI_TARGET_DIR) \
-                                  --no-default-features --features compression
+                                  --no-default-features --features cli,compression
 
 $(RUST_COMPRESS_CLI_STATICLIB): $(RUST_CLI_SOURCES)
 	$(CARGO) build $(RUST_COMPRESS_CLI_CARGO_FLAGS)
diff --git a/programs/timefn.c b/programs/timefn.c
index 4f045226b..349bd26dc 100644
--- a/programs/timefn.c
+++ b/programs/timefn.c
@@ -8,161 +8,14 @@
  * You may select, at your option, one of the above-listed licenses.
  */
 
-
-/* ===  Dependencies  === */
+/* The implementation lives in rust/src/timefn.rs, built into the Rust CLI
+ * static archive. This translation unit stays in the original source lists so
+ * build configuration keeps working while the implementation is in Rust. */
 
 #include "timefn.h"
-#include "platform.h" /* set _POSIX_C_SOURCE */
-#include <time.h>     /* CLOCK_MONOTONIC, TIME_UTC */
 
-/*-****************************************
-*  Time functions
-******************************************/
-
-#if defined(_WIN32)   /* Windows */
-
-#include <windows.h>  /* LARGE_INTEGER */
-#include <stdlib.h>   /* abort */
-#include <stdio.h>    /* perror */
-
-UTIL_time_t UTIL_getTime(void)
-{
-    static LARGE_INTEGER ticksPerSecond;
-    static int init = 0;
-    if (!init) {
-        if (!QueryPerformanceFrequency(&ticksPerSecond)) {
-            perror("timefn::QueryPerformanceFrequency");
-            abort();
-        }
-        init = 1;
-    }
-    {   UTIL_time_t r;
-        LARGE_INTEGER x;
-        QueryPerformanceCounter(&x);
-        r.t = (PTime)(x.QuadPart * 1000000000ULL / ticksPerSecond.QuadPart);
-        return r;
-    }
-}
-
-
-#elif defined(__APPLE__) && defined(__MACH__)
-
-#include <mach/mach_time.h> /* mach_timebase_info_data_t, mach_timebase_info, mach_absolute_time */
-
-UTIL_time_t UTIL_getTime(void)
-{
-    static mach_timebase_info_data_t rate;
-    static int init = 0;
-    if (!init) {
-        mach_timebase_info(&rate);
-        init = 1;
-    }
-    {   UTIL_time_t r;
-        r.t = mach_absolute_time() * (PTime)rate.numer / (PTime)rate.denom;
-        return r;
-    }
-}
-
-/* POSIX.1-2001 (optional) */
-#elif defined(CLOCK_MONOTONIC)
-
-#include <stdlib.h>   /* abort */
-#include <stdio.h>    /* perror */
-
-UTIL_time_t UTIL_getTime(void)
-{
-    /* time must be initialized, othersize it may fail msan test.
-     * No good reason, likely a limitation of timespec_get() for some target */
-    struct timespec time = { 0, 0 };
-    if (clock_gettime(CLOCK_MONOTONIC, &time) != 0) {
-        perror("timefn::clock_gettime(CLOCK_MONOTONIC)");
-        abort();
-    }
-    {   UTIL_time_t r;
-        r.t = (PTime)time.tv_sec * 1000000000ULL + (PTime)time.tv_nsec;
-        return r;
-    }
-}
-
-
-/* C11 requires support of timespec_get().
- * However, FreeBSD 11 claims C11 compliance while lacking timespec_get().
- * Double confirm timespec_get() support by checking the definition of TIME_UTC.
- * However, some versions of Android manage to simultaneously define TIME_UTC
- * and lack timespec_get() support... */
-#elif (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */) \
-    && defined(TIME_UTC) && !defined(__ANDROID__)
-
-#include <stdlib.h>   /* abort */
-#include <stdio.h>    /* perror */
-
-UTIL_time_t UTIL_getTime(void)
-{
-    /* time must be initialized, othersize it may fail msan test.
-     * No good reason, likely a limitation of timespec_get() for some target */
-    struct timespec time = { 0, 0 };
-    if (timespec_get(&time, TIME_UTC) != TIME_UTC) {
-        perror("timefn::timespec_get(TIME_UTC)");
-        abort();
-    }
-    {   UTIL_time_t r;
-        r.t = (PTime)time.tv_sec * 1000000000ULL + (PTime)time.tv_nsec;
-        return r;
-    }
-}
-
-
-#else   /* relies on standard C90 (note : clock_t produces wrong measurements for multi-threaded workloads) */
-
-UTIL_time_t UTIL_getTime(void)
-{
-    UTIL_time_t r;
-    r.t = (PTime)clock() * 1000000000ULL / CLOCKS_PER_SEC;
-    return r;
-}
-
-#define TIME_MT_MEASUREMENTS_NOT_SUPPORTED
-
-#endif
-
-/* ==== Common functions, valid for all time API ==== */
-
-PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd)
-{
-    return clockEnd.t - clockStart.t;
-}
-
-PTime UTIL_getSpanTimeMicro(UTIL_time_t begin, UTIL_time_t end)
-{
-    return UTIL_getSpanTimeNano(begin, end) / 1000ULL;
-}
-
-PTime UTIL_clockSpanMicro(UTIL_time_t clockStart )
-{
-    UTIL_time_t const clockEnd = UTIL_getTime();
-    return UTIL_getSpanTimeMicro(clockStart, clockEnd);
-}
-
-PTime UTIL_clockSpanNano(UTIL_time_t clockStart )
-{
-    UTIL_time_t const clockEnd = UTIL_getTime();
-    return UTIL_getSpanTimeNano(clockStart, clockEnd);
-}
-
-void UTIL_waitForNextTick(void)
-{
-    UTIL_time_t const clockStart = UTIL_getTime();
-    UTIL_time_t clockEnd;
-    do {
-        clockEnd = UTIL_getTime();
-    } while (UTIL_getSpanTimeNano(clockStart, clockEnd) == 0);
-}
-
-int UTIL_support_MT_measurements(void)
-{
-# if defined(TIME_MT_MEASUREMENTS_NOT_SUPPORTED)
-    return 0;
-# else
-    return 1;
-# endif
-}
+/* The Rust port mirrors this exact ABI: UTIL_time_t is returned by value and
+ * must remain a plain 64-bit nanosecond counter. */
+typedef char UTIL_staticAssert_ptimeIs64Bit[(sizeof(PTime) == 8) ? 1 : -1];
+typedef char UTIL_staticAssert_timeIsPlainCounter[
+    (sizeof(UTIL_time_t) == sizeof(PTime)) ? 1 : -1];
diff --git a/rust/README.md b/rust/README.md
index 0dc056c7e..ff4502bcc 100644
--- a/rust/README.md
+++ b/rust/README.md
@@ -69,6 +69,11 @@ zstd ABI:
     so library builds do not acquire program-only dependencies.  The C
     `fileio` backend still owns file opening, safe replacement, sparse writes,
     metadata, and streaming I/O.
+  - `timefn` provides the monotonic nanosecond clock behind `UTIL_time_t`.
+    It also lives in the `cli/` package, but C test binaries (fullbench,
+    fuzzer, zstreamtest, paramgrill, ...) link a helpers-only build of that
+    archive, produced without the package's `cli` feature, because the parser
+    layer requires the C `fileio` backend that tests do not compile.
 
 The optimal block matcher, high-level frame compression, dictionary-building
 except suffix-array construction, legacy decoding callbacks, and the CLI
@@ -111,8 +116,9 @@ from `rust/cli` as well:
 ```sh
 cargo clippy --all-targets -- -D warnings
 cargo test --all-targets
-cargo test --no-default-features --features compression --all-targets
-cargo test --no-default-features --features decompression --all-targets
+cargo test --no-default-features --features cli,compression --all-targets
+cargo test --no-default-features --features cli,decompression --all-targets
+cargo test --no-default-features --all-targets
 ```
 
 Then run original compatibility tests from the repository root, starting with
diff --git a/rust/cli/Cargo.lock b/rust/cli/Cargo.lock
index dc58719bc..ab11ff18b 100644
--- a/rust/cli/Cargo.lock
+++ b/rust/cli/Cargo.lock
@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "libc"
+version = "0.2.186"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68ab91017fe16c622486840e4c83c9a37afeff978bd239b5293d61ece587de66"
+
 [[package]]
 name = "zstd-cli-rs"
 version = "0.1.0"
+dependencies = [
+ "libc",
+]
diff --git a/rust/cli/Cargo.toml b/rust/cli/Cargo.toml
index 99830b3f5..d4c14a623 100644
--- a/rust/cli/Cargo.toml
+++ b/rust/cli/Cargo.toml
@@ -7,6 +7,13 @@ edition = "2021"
 crate-type = ["staticlib"]
 
 [features]
-default = ["compression", "decompression"]
+default = ["cli", "compression", "decompression"]
+# The command-line parser and dispatch layer, which requires the C fileio
+# backend at link time. Program archives enable it; C test binaries link a
+# helpers-only archive (timefn) built without it.
+cli = []
 compression = []
 decompression = []
+
+[dependencies]
+libc = "0.2"
diff --git a/rust/cli/src/lib.rs b/rust/cli/src/lib.rs
index 458d3ef36..e33acb81b 100644
--- a/rust/cli/src/lib.rs
+++ b/rust/cli/src/lib.rs
@@ -1,2 +1,5 @@
+#[path = "../../src/timefn.rs"]
+mod timefn;
+#[cfg(feature = "cli")]
 #[path = "../../src/zstd_cli.rs"]
 mod zstd_cli;
diff --git a/rust/src/timefn.rs b/rust/src/timefn.rs
new file mode 100644
index 000000000..c6e97129a
--- /dev/null
+++ b/rust/src/timefn.rs
@@ -0,0 +1,198 @@
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+
+//! Precise monotonic time measurement for the command-line programs.
+//!
+//! Port of `programs/timefn.c`.  `UTIL_time_t` is a plain nanosecond counter
+//! whose absolute value is meaningless; only spans between two measurements
+//! are valid.  The struct crosses the C ABI by value, so it stays `repr(C)`
+//! with the exact `timefn.h` layout.
+//!
+//! Platform selection mirrors the C preprocessor structure: Windows uses the
+//! performance counter, Apple systems use the Mach absolute clock, and other
+//! POSIX systems use `clock_gettime(CLOCK_MONOTONIC)`.  The C90 `clock()`
+//! fallback is never needed on targets Rust supports, so multi-threaded
+//! measurements are always supported.
+
+use std::os::raw::c_int;
+
+/// Precise Time (`PTime` in timefn.h): an unsigned 64-bit nanosecond count.
+pub type PTime = u64;
+
+/// Nanosecond time counter with the `timefn.h` `UTIL_time_t` layout.
+#[repr(C)]
+#[derive(Clone, Copy, Debug)]
+pub struct UTIL_time_t {
+    pub t: PTime,
+}
+
+const _: () = assert!(std::mem::size_of::<PTime>() == 8);
+const _: () = assert!(std::mem::size_of::<UTIL_time_t>() == std::mem::size_of::<PTime>());
+
+#[cfg(windows)]
+mod platform {
+    use super::PTime;
+    use std::sync::OnceLock;
+
+    #[link(name = "kernel32")]
+    unsafe extern "system" {
+        /// Takes a `LARGE_INTEGER*`; the union is ABI-identical to `i64*`.
+        fn QueryPerformanceCounter(count: *mut i64) -> i32;
+        fn QueryPerformanceFrequency(frequency: *mut i64) -> i32;
+    }
+
+    pub fn monotonic_ns() -> PTime {
+        static TICKS_PER_SECOND: OnceLock<i64> = OnceLock::new();
+        let ticks_per_second = *TICKS_PER_SECOND.get_or_init(|| {
+            let mut frequency = 0i64;
+            if unsafe { QueryPerformanceFrequency(&mut frequency) } == 0 {
+                eprintln!(
+                    "timefn::QueryPerformanceFrequency: {}",
+                    std::io::Error::last_os_error()
+                );
+                std::process::abort();
+            }
+            frequency
+        });
+        let mut counter = 0i64;
+        unsafe { QueryPerformanceCounter(&mut counter) };
+        (counter as PTime).wrapping_mul(1_000_000_000) / ticks_per_second as PTime
+    }
+}
+
+#[cfg(all(unix, target_vendor = "apple"))]
+mod platform {
+    use super::PTime;
+    use std::sync::OnceLock;
+
+    pub fn monotonic_ns() -> PTime {
+        static RATE: OnceLock<(PTime, PTime)> = OnceLock::new();
+        let (numer, denom) = *RATE.get_or_init(|| {
+            let mut rate = libc::mach_timebase_info { numer: 0, denom: 0 };
+            unsafe { libc::mach_timebase_info(&mut rate) };
+            (PTime::from(rate.numer), PTime::from(rate.denom))
+        });
+        unsafe { libc::mach_absolute_time() }.wrapping_mul(numer) / denom
+    }
+}
+
+#[cfg(all(unix, not(target_vendor = "apple")))]
+mod platform {
+    use super::PTime;
+
+    pub fn monotonic_ns() -> PTime {
+        // Zero-initialized like the C source, which works around timespec_get
+        // msan limitations on some targets.
+        let mut time: libc::timespec = unsafe { std::mem::zeroed() };
+        if unsafe { libc::clock_gettime(libc::CLOCK_MONOTONIC, &mut time) } != 0 {
+            eprintln!(
+                "timefn::clock_gettime(CLOCK_MONOTONIC): {}",
+                std::io::Error::last_os_error()
+            );
+            std::process::abort();
+        }
+        (time.tv_sec as PTime)
+            .wrapping_mul(1_000_000_000)
+            .wrapping_add(time.tv_nsec as PTime)
+    }
+}
+
+/// Returns the current value of the platform's monotonic nanosecond clock.
+#[no_mangle]
+pub extern "C" fn UTIL_getTime() -> UTIL_time_t {
+    UTIL_time_t {
+        t: platform::monotonic_ns(),
+    }
+}
+
+/// Nanoseconds elapsed between two measurements, with C unsigned wrap-around.
+#[no_mangle]
+pub extern "C" fn UTIL_getSpanTimeNano(clockStart: UTIL_time_t, clockEnd: UTIL_time_t) -> PTime {
+    clockEnd.t.wrapping_sub(clockStart.t)
+}
+
+/// Microseconds elapsed between two measurements, truncated like C division.
+#[no_mangle]
+pub extern "C" fn UTIL_getSpanTimeMicro(begin: UTIL_time_t, end: UTIL_time_t) -> PTime {
+    UTIL_getSpanTimeNano(begin, end) / 1000
+}
+
+/// Microseconds elapsed since `clockStart`.
+#[no_mangle]
+pub extern "C" fn UTIL_clockSpanMicro(clockStart: UTIL_time_t) -> PTime {
+    UTIL_getSpanTimeMicro(clockStart, UTIL_getTime())
+}
+
+/// Nanoseconds elapsed since `clockStart`.
+#[no_mangle]
+pub extern "C" fn UTIL_clockSpanNano(clockStart: UTIL_time_t) -> PTime {
+    UTIL_getSpanTimeNano(clockStart, UTIL_getTime())
+}
+
+/// Busy-waits until the clock produces a new tick, improving measurement
+/// accuracy on platforms with a low timer resolution.
+#[no_mangle]
+pub extern "C" fn UTIL_waitForNextTick() {
+    let clockStart = UTIL_getTime();
+    loop {
+        let clockEnd = UTIL_getTime();
+        if UTIL_getSpanTimeNano(clockStart, clockEnd) != 0 {
+            return;
+        }
+    }
+}
+
+/// All clock sources used by the Rust port are valid under multi-threaded
+/// workloads; only the C90 `clock()` fallback of the C source was not.
+#[no_mangle]
+pub extern "C" fn UTIL_support_MT_measurements() -> c_int {
+    1
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn nanosecond_spans_subtract_with_unsigned_wrap_around() {
+        let start = UTIL_time_t { t: 100 };
+        let end = UTIL_time_t { t: 350 };
+
+        assert_eq!(UTIL_getSpanTimeNano(start, end), 250);
+        assert_eq!(UTIL_getSpanTimeNano(end, start), u64::MAX - 249);
+        assert_eq!(UTIL_getSpanTimeNano(start, start), 0);
+    }
+
+    #[test]
+    fn microsecond_spans_truncate_sub_tick_remainders() {
+        let start = UTIL_time_t { t: 0 };
+
+        assert_eq!(UTIL_getSpanTimeMicro(start, UTIL_time_t { t: 999 }), 0);
+        assert_eq!(UTIL_getSpanTimeMicro(start, UTIL_time_t { t: 1_000 }), 1);
+        assert_eq!(UTIL_getSpanTimeMicro(start, UTIL_time_t { t: 1_999 }), 1);
+        assert_eq!(UTIL_getSpanTimeMicro(start, UTIL_time_t { t: 2_000 }), 2);
+    }
+
+    #[test]
+    fn clock_is_monotonic_across_measurements() {
+        let first = UTIL_getTime();
+        let second = UTIL_getTime();
+
+        assert!(second.t >= first.t);
+        assert!(UTIL_clockSpanNano(first) >= UTIL_getSpanTimeNano(first, second));
+    }
+
+    #[test]
+    fn waiting_for_the_next_tick_advances_the_clock() {
+        let before = UTIL_getTime();
+        UTIL_waitForNextTick();
+        let after = UTIL_getTime();
+
+        assert!(UTIL_getSpanTimeNano(before, after) > 0);
+    }
+
+    #[test]
+    fn multi_threaded_measurements_are_supported() {
+        assert_eq!(UTIL_support_MT_measurements(), 1);
+    }
+}
diff --git a/tests/Makefile b/tests/Makefile
index e986fb237..15c1f1cdf 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -93,6 +93,28 @@ $(RUST_STATICLIB): $(RUST_SOURCES)
 $(RUST_STATICLIB_32): $(RUST_SOURCES)
 	$(CARGO) build $(RUST_CARGO_FLAGS) --target $(RUST_TARGET_32)
 
+# Program-only helpers that were C sources shared with the tests (timefn,
+# benchfn) now live in the Rust CLI package. The tests link a helpers-only
+# archive, built without the `cli` feature: the parser/dispatch layer needs
+# the C fileio backend, which test binaries do not provide.
+RUST_CLI_DIR := $(RUST_DIR)/cli
+RUST_CLI_MANIFEST := $(RUST_CLI_DIR)/Cargo.toml
+RUST_CLI_HELPER_SOURCES := $(RUST_CLI_MANIFEST) $(RUST_CLI_DIR)/Cargo.lock \
+                           $(RUST_CLI_DIR)/src/lib.rs \
+                           $(RUST_DIR)/src/timefn.rs
+RUST_CLI_HELPERS_TARGET_DIR := $(RUST_DIR)/target/cli-helpers
+RUST_CLI_HELPERS_STATICLIB := $(RUST_CLI_HELPERS_TARGET_DIR)/release/libzstd_cli_rs.a
+RUST_CLI_HELPERS_STATICLIB_32 := $(RUST_CLI_HELPERS_TARGET_DIR)/$(RUST_TARGET_32)/release/libzstd_cli_rs.a
+RUST_CLI_HELPERS_CARGO_FLAGS := --manifest-path $(RUST_CLI_MANIFEST) --release \
+                                --target-dir $(RUST_CLI_HELPERS_TARGET_DIR) \
+                                --no-default-features
+
+$(RUST_CLI_HELPERS_STATICLIB): $(RUST_CLI_HELPER_SOURCES)
+	$(CARGO) build $(RUST_CLI_HELPERS_CARGO_FLAGS)
+
+$(RUST_CLI_HELPERS_STATICLIB_32): $(RUST_CLI_HELPER_SOURCES)
+	$(CARGO) build $(RUST_CLI_HELPERS_CARGO_FLAGS) --target $(RUST_TARGET_32)
+
 # These test objects have flat filenames, unlike the configuration-hashed
 # program objects. Track the HUF mode separately so a C object set compiled
 # for one decoder is never relinked with a Rust archive for another decoder.
@@ -252,8 +274,8 @@ fuzzer32 : $(ZSTD_FILES)
 	$(LINK.c) $^ -o $@$(EXT)
 
 # note : broken : requires symbols unavailable from dynamic library
-fuzzer-dll : $(LIB_SRCDIR)/common/xxhash.c $(PRGDIR)/util.c $(PRGDIR)/timefn.c $(PRGDIR)/datagen.c fuzzer.c
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(filter %.c,$^) $(LDFLAGS) -o $@$(EXT)
+fuzzer-dll : $(LIB_SRCDIR)/common/xxhash.c $(PRGDIR)/util.c $(PRGDIR)/timefn.c $(PRGDIR)/datagen.c fuzzer.c $(RUST_CLI_HELPERS_STATICLIB)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(filter %.c,$^) $(RUST_CLI_HELPERS_STATICLIB) $(LDFLAGS) -o $@$(EXT)
 
 CLEAN += zstreamtest zstreamtest32
 ZSTREAM_LOCAL_FILES := $(PRGDIR)/datagen.c $(PRGDIR)/util.c $(PRGDIR)/timefn.c seqgen.c zstreamtest.c external_matchfinder.c
@@ -284,8 +306,8 @@ zstreamtest_ubsan : $(ZSTREAMFILES)
 
 # note : broken : requires symbols unavailable from dynamic library
 zstreamtest-dll : $(LIB_SRCDIR)/common/xxhash.c  # xxh symbols not exposed from dll
-zstreamtest-dll : $(ZSTREAM_LOCAL_FILES)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(filter %.c,$^) $(LDFLAGS) -o $@$(EXT)
+zstreamtest-dll : $(ZSTREAM_LOCAL_FILES) $(RUST_CLI_HELPERS_STATICLIB)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(filter %.c,$^) $(RUST_CLI_HELPERS_STATICLIB) $(LDFLAGS) -o $@$(EXT)
 
 CLEAN += paramgrill
 paramgrill : DEBUGFLAGS =   # turn off debug for speed measurements
@@ -344,6 +366,17 @@ $(RUST_LINK_TARGETS_32): $(RUST_STATICLIB_32)
 
 $(RUST_LINK_TARGETS) $(RUST_LINK_TARGETS_32): $(RUST_HUF_C_MODE_STAMP)
 
+# Tests that compile the timefn/benchfn C shims also link the Rust CLI
+# helpers archive, which owns those implementations. The archive is a
+# prerequisite so `$^` places it after every C object referencing its symbols.
+RUST_CLI_LINK_TARGETS := fullbench fullbench-lib fullbench-dll fuzzer \
+                         zstreamtest zstreamtest_asan zstreamtest_tsan \
+                         zstreamtest_ubsan paramgrill decodecorpus poolTests
+$(RUST_CLI_LINK_TARGETS): $(RUST_CLI_HELPERS_STATICLIB)
+
+RUST_CLI_LINK_TARGETS_32 := fullbench32 fuzzer32 zstreamtest32
+$(RUST_CLI_LINK_TARGETS_32): $(RUST_CLI_HELPERS_STATICLIB_32)
+
 .PHONY: versionsTest
 versionsTest: clean
 	$(PYTHON) test-zstd-versions.py