Build system changes for v22.0.0 (#4522)

This is a sequence of cherry picks of (mostly) miscellaneous
build-system infrastructure that I've recently landed on master
transplanted onto the v22.0.0 branch.

Each somewhat improves the build situation (eg. enabling tracy,
disabling memory tracking, fixing asan, cleaning more thoroughly,
forcing rust toolchain version identity) but none of them are essential
for making the v22.0.0 release. You could take any or none of them,
it'll be ok either way.

There is also
72c5f9d
which removes some stale cost-type adjustments in BUILD_TESTS-only code
that's only active if you do multi-protocol replay -- the thing where we
can run one tx twice, once on p21 and once on p22 -- and it might be
nice to have that fixed so that we can do some more-confidence-inspiring
side-by-side testing of p21 txs on the p22 codebase before the upgrade.
But again it's really just a nice-to-have, none of this is essential.

Builds/VisualStudio/stellar-core.vcxproj

@@ -325,7 +325,7 @@ exit /b 0
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
-      <PreprocessorDefinitions>CEREAL_THREAD_SAFE;USE_POSTGRES;ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION=1;USE_SPDLOG;FMT_HEADER_ONLY=1;BUILD_TESTS;WIN32_LEAN_AND_MEAN;NOMINMAX;ASIO_STANDALONE;_WINSOCK_DEPRECATED_NO_WARNINGS;SODIUM_STATIC;ASIO_SEPARATE_COMPILATION;ASIO_ERROR_CATEGORY_NOEXCEPT=noexcept;TRACY_ENABLE;TRACY_ON_DEMAND;TRACY_NO_BROADCAST;TRACY_ONLY_LOCALHOST;TRACY_DELAYED_INIT;TRACY_MANUAL_LIFETIME;USE_TRACY;_CRT_SECURE_NO_WARNINGS;_WIN32_WINNT=0x0601;WIN32;_MBCS;_CRT_NONSTDC_NO_DEPRECATE;YY_NO_UNISTD_H;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>CEREAL_THREAD_SAFE;USE_POSTGRES;ENABLE_NEXT_PROTOCOL_VERSION_UNSAFE_FOR_PRODUCTION=1;USE_SPDLOG;FMT_HEADER_ONLY=1;BUILD_TESTS;WIN32_LEAN_AND_MEAN;NOMINMAX;ASIO_STANDALONE;_WINSOCK_DEPRECATED_NO_WARNINGS;SODIUM_STATIC;ASIO_SEPARATE_COMPILATION;ASIO_ERROR_CATEGORY_NOEXCEPT=noexcept;TRACY_ENABLE;TRACY_ON_DEMAND;TRACY_NO_BROADCAST;TRACY_ONLY_LOCALHOST;TRACY_DELAYED_INIT;USE_TRACY;_CRT_SECURE_NO_WARNINGS;_WIN32_WINNT=0x0601;WIN32;_MBCS;_CRT_NONSTDC_NO_DEPRECATE;YY_NO_UNISTD_H;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>src;../../src;../../lib;../../lib/tracy/public/tracy;../../lib/spdlog/include;../../lib/libmedida/src;../../lib/soci/src/core;../../lib/autocheck/include;../../lib/cereal/include;../../lib/asio/asio/include;../../lib/xdrpp;../../lib/libsodium/src/libsodium/include;../../lib/fmt/include;../../lib/util;../..;src/$(Configuration)/generated;../../lib/sqlite;c:\Program Files\PostgreSQL\15\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <BrowseInformation>false</BrowseInformation>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
@@ -390,7 +390,7 @@ exit /b 0
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
-      <PreprocessorDefinitions>CEREAL_THREAD_SAFE;USE_POSTGRES;USE_SPDLOG;FMT_HEADER_ONLY=1;BUILD_TESTS;WIN32_LEAN_AND_MEAN;NOMINMAX;ASIO_STANDALONE;_WINSOCK_DEPRECATED_NO_WARNINGS;SODIUM_STATIC;ASIO_SEPARATE_COMPILATION;ASIO_ERROR_CATEGORY_NOEXCEPT=noexcept;TRACY_ENABLE;TRACY_ON_DEMAND;TRACY_NO_BROADCAST;TRACY_ONLY_LOCALHOST;TRACY_DELAYED_INIT;TRACY_MANUAL_LIFETIME;USE_TRACY;_CRT_SECURE_NO_WARNINGS;_WIN32_WINNT=0x0601;WIN32;_MBCS;_CRT_NONSTDC_NO_DEPRECATE;YY_NO_UNISTD_H;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>CEREAL_THREAD_SAFE;USE_POSTGRES;USE_SPDLOG;FMT_HEADER_ONLY=1;BUILD_TESTS;WIN32_LEAN_AND_MEAN;NOMINMAX;ASIO_STANDALONE;_WINSOCK_DEPRECATED_NO_WARNINGS;SODIUM_STATIC;ASIO_SEPARATE_COMPILATION;ASIO_ERROR_CATEGORY_NOEXCEPT=noexcept;TRACY_ENABLE;TRACY_ON_DEMAND;TRACY_NO_BROADCAST;TRACY_ONLY_LOCALHOST;TRACY_DELAYED_INIT;USE_TRACY;_CRT_SECURE_NO_WARNINGS;_WIN32_WINNT=0x0601;WIN32;_MBCS;_CRT_NONSTDC_NO_DEPRECATE;YY_NO_UNISTD_H;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>src;../../src;../../lib;../../lib/tracy/public/tracy;../../lib/spdlog/include;../../lib/libmedida/src;../../lib/soci/src/core;../../lib/autocheck/include;../../lib/cereal/include;../../lib/asio/asio/include;../../lib/xdrpp;../../lib/libsodium/src/libsodium/include;../../lib/fmt/include;../../lib/util;../..;src/$(Configuration)/generated;../../lib/sqlite;c:\Program Files\PostgreSQL\15\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <BrowseInformation>false</BrowseInformation>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>

configure.ac

@@ -347,7 +347,7 @@ AC_ARG_ENABLE(tracy,
     AS_HELP_STRING([--enable-tracy],
         [Enable 'tracy' profiler/tracer client stub]))
 AM_CONDITIONAL(USE_TRACY, [test x$enable_tracy = xyes])
-tracy_CFLAGS='-DTRACY_ENABLE -DTRACY_ON_DEMAND -DTRACY_NO_BROADCAST -DTRACY_ONLY_LOCALHOST -DTRACY_ONLY_IPV4 -DTRACY_DELAYED_INIT -DTRACY_MANUAL_LIFETIME'
+tracy_CFLAGS='-DTRACY_ENABLE -DTRACY_ON_DEMAND -DTRACY_NO_BROADCAST -DTRACY_ONLY_LOCALHOST -DTRACY_ONLY_IPV4 -DTRACY_DELAYED_INIT'
 if test x"$enable_tracy" = xyes; then
     case "${host_os}" in
         *darwin*)
@@ -359,6 +359,14 @@ if test x"$enable_tracy" = xyes; then
 fi
 AC_SUBST(tracy_CFLAGS)
 
+AC_ARG_ENABLE(tracy-memory-tracking,
+    AS_HELP_STRING([--enable-tracy-memory-tracking],
+        [Enable 'tracy' profiler/tracer memory tracking code (slow)]))
+AM_CONDITIONAL(USE_TRACY_MEMORY_TRACKING, [test x$enable_tracy_memory_tracking = xyes])
+if test x"$enable_tracy_memory_tracking" = xyes -a x"$enable_asan" = xyes; then
+       AC_MSG_ERROR([--enable-asan is not compatible with --enable-tracy-memory-tracking])
+fi
+
 AC_ARG_ENABLE(tracy-gui,
     AS_HELP_STRING([--enable-tracy-gui],
         [Enable 'tracy' profiler/tracer server GUI]))

src/Makefile.am

@@ -8,8 +8,54 @@ include $(srcdir)/src.mk
 
 noinst_HEADERS = $(SRC_H_FILES)
 
+# We sometimes specify a CXXFLAGS setting like -stdlib=libc++ that causes the
+# stdlib to change. When this makes it way down to Rust code building C++ code
+# for one of its libraries (specifically tracy-client-sys) this needs to be
+# accompanied by an _explicit_ instruction to invoke the linker with -lc++. This
+# is done by setting the CXXSTDLIB flag, which Rust's C++-building machinery is
+# sensitive to. Rust passes-on, but does not look inside, CXXFLAGS itself to
+# realize that it needs this setting.
+CXXSTDLIB := $(if $(findstring -stdlib=libc++,$(CXXFLAGS)),c++,$(if $(findstring -stdlib=libstdc++,$(CXXFLAGS)),stdc++,))
+
+# If we are building with -fsanitize=address, any build.rs-built C++ code will
+# depend on asan, so we need to tell rustc to link with in the asan runtime as
+# well. Interestingly, passing -Clink-arg=-fsanitize=address to rustc does not
+# work, despite being the recommended approach, it seems rustc passes some other
+# flags to the linker that conflict with -fsanitize=address.
+RUSTFLAGS_ASAN := $(if $(findstring -fsanitize=address,$(CXXFLAGS)),-Clink-arg=-lasan,)
+
 if USE_TRACY
+# NB: this unfortunately long list has to be provided here and kept in sync with
+# the list of features for tracy-client in src/rust/Cargo.toml.  This is because
+# the soroban sub-crates are built independently and know nothing about
+# src/rust/Cargo.toml
+#
+# NB also: this list does _not_ and should not include the manual-lifetime
+# feature. Versions of the rust tracy-client crate before 0.17 (eg. version
+# 0.16.4 which we shipped in soroban 21.x) always used the C++ tracy code in
+# manual-lifetime mode, and thus required careful coordination with
+# stellar-core's C++ code to start and stop tracy correctly. However this became
+# intractable when we started building multiple soroban libraries as .rlibs with
+# separate copies of tracy-client simultaneously, as they would each have their
+# own rust-metadata-hash-qualified copy of a rust global variable tracking the
+# initialization state of tracy (and of course tracy's C++ code itself cannot be
+# started multiple times idempotently in manual-lifetime mode, that would be too
+# easy). So we have now disabled tracy-client (0.16.4) in soroban 21.x and only
+# enabled it in soroban 22.x (and later), which has tracy-client 0.17, which
+# finally supports _turning off_ manual-lifetime mode. Once off, tracy's C++
+# code initializes itself on its own, and everything works fine. There is only
+# one copy of tracy in the final linked executable and it has a single atomic
+# pointer controlling its initialization state.
 CARGO_FEATURE_TRACY = --features tracy
+CARGO_FEATURE_TRACY += --features tracy-client/enable
+CARGO_FEATURE_TRACY += --features tracy-client/ondemand
+CARGO_FEATURE_TRACY += --features tracy-client/delayed-init
+CARGO_FEATURE_TRACY += --features tracy-client/system-tracing
+CARGO_FEATURE_TRACY += --features tracy-client/sampling
+CARGO_FEATURE_TRACY += --features tracy-client/code-transfer
+CARGO_FEATURE_TRACY += --features tracy-client/timer-fallback
+CARGO_FEATURE_TRACY += --features tracy-client/only-localhost
+CARGO_FEATURE_TRACY += --features tracy-client/only-ipv4
 else
 CARGO_FEATURE_TRACY =
 endif
@@ -76,6 +122,10 @@ stellar_core_SOURCES += util/xdrquery/XDRQueryScanner.cpp util/xdrquery/XDRQuery
 BUILT_SOURCES += rust/RustBridge.h rust/RustBridge.cpp
 stellar_core_SOURCES += rust/RustBridge.h rust/RustBridge.cpp
 
+RUST_TOOLCHAIN_FILE=$(top_srcdir)/rust-toolchain.toml
+RUST_TOOLCHAIN_CHANNEL=$(shell sed -n 's/channel *= *"\([^"]*\)"/\1/p' $(RUST_TOOLCHAIN_FILE))
+CARGO=cargo +$(RUST_TOOLCHAIN_CHANNEL)
+
 RUST_BUILD_DIR=$(top_builddir)/src/rust
 RUST_BIN_DIR=$(RUST_BUILD_DIR)/bin
 RUST_TARGET_DIR=$(top_builddir)/target
@@ -111,9 +161,9 @@ ALL_SOROBAN_LIBS=$(foreach proto,$(ALL_SOROBAN_PROTOCOLS),$(call soroban_rlib,$(
 ALL_SOROBAN_EXTERN_ARGS=$(foreach proto,$(ALL_SOROBAN_PROTOCOLS),$(call soroban_extern_flag,$(proto)))
 ALL_SOROBAN_DEPEND_ARGS=$(foreach proto,$(ALL_SOROBAN_PROTOCOLS),$(call soroban_depend_flag,$(proto)))
 
-$(RUST_CXXBRIDGE):
+$(RUST_CXXBRIDGE): Makefile $(RUST_TOOLCHAIN_FILE)
 	mkdir -p $(RUST_BIN_DIR)
-	CARGO_HTTP_MULTIPLEXING=false $(CARGO) install --locked --root $(RUST_BUILD_DIR) cxxbridge-cmd --version 1.0.68
+	CARGO_HTTP_MULTIPLEXING=false $(CARGO) install --force --locked --root $(RUST_BUILD_DIR) cxxbridge-cmd --version 1.0.68
 
 rust/RustBridge.h: rust/src/lib.rs $(SRC_RUST_FILES) Makefile $(RUST_CXXBRIDGE)
 	$(RUST_CXXBRIDGE) $< --cfg test=false --header --output $@.tmp
@@ -127,11 +177,11 @@ rust/RustBridge.cpp: rust/src/lib.rs $(SRC_RUST_FILES) Makefile $(RUST_CXXBRIDGE
 # check in to this repo as a secondary check on the lockfiles in the soroban
 # submodules. You should still carefully inspect them if they change!
 
-$(RUST_DEP_TREE_STAMP): $(wildcard rust/soroban/*/Cargo.*) Makefile
+$(RUST_DEP_TREE_STAMP): $(wildcard rust/soroban/*/Cargo.*) Makefile $(RUST_TOOLCHAIN_FILE)
 	rm -f $@
 	for proto in $(ALL_SOROBAN_PROTOCOLS); \
 	do \
-		cargo tree --manifest-path rust/soroban/$${proto}/Cargo.toml --locked --package soroban-env-host --edges no-dev --target all \
+		$(CARGO) tree --manifest-path rust/soroban/$${proto}/Cargo.toml --locked --package soroban-env-host --edges no-dev --target all \
 		| sed -e "s@$(abspath $(top_srcdir))/@@g" > $(RUST_BUILD_DIR)/src/dep-trees/$${proto}-actual.txt ; \
 		if ! diff -u rust/src/dep-trees/$${proto}-expect.txt $(RUST_BUILD_DIR)/src/dep-trees/$${proto}-actual.txt; \
 		then \
@@ -167,15 +217,24 @@ $(RUST_DEP_TREE_STAMP): $(wildcard rust/soroban/*/Cargo.*) Makefile
 # them back together. Or something. Anyways it works and is the only portable
 # and robust solution we've found to preventing the StableCrateId collision.
 #
-# We also have to be somewhat selective about the versions we pass the
-# `next` feature to (only the most recent soroban) and the versions we
-# pass the `tracy` feature to (only those post-p22 versions that support
-# the tracy delayed-init feature).
+# We also have to be somewhat selective about the versions we pass the `next`
+# feature to (only the most recent soroban) and the versions we pass the `tracy`
+# features to (only those post-p22 versions that support the tracy delayed-init
+# feature).
 #
 # We also have to sequentialize the builds of the sorobans after the
-# dep-tree-stamp files and before the stellar-core build, because rustup
-# gets invoked and it is not concurrency-safe.
-$(SOROBAN_LIBS_STAMP): $(wildcard rust/soroban/p*/Cargo.lock) Makefile $(RUST_DEP_TREE_STAMP) $(SRC_RUST_FILES)
+# dep-tree-stamp files and before the stellar-core build, because rustup gets
+# invoked and it is not concurrency-safe.
+#
+# We also have to set pass all the CC, CXX, CFLAGS and CXXFLAGS we were called
+# with explicitly, because make does not implicitly export them to its rules,
+# but cargo needs them to build C++ files in build.rs files.
+#
+# We also have to pass CXXSTDLIB to those build.rs files, because they are
+# sensitive to CXXFLAGS but also don't inspect them to see if they're setting
+# -stdlib=libc++ or -stdlib=libstdc++
+$(SOROBAN_LIBS_STAMP): $(wildcard rust/soroban/p*/Cargo.lock) Makefile $(RUST_DEP_TREE_STAMP) $(SRC_RUST_FILES) $(RUST_TOOLCHAIN_FILE)
+	rm -f $@
 	for proto in $(ALL_SOROBAN_PROTOCOLS) ; \
 	do \
 		FEATURE_FLAGS="" ; \
@@ -191,8 +250,10 @@ $(SOROBAN_LIBS_STAMP): $(wildcard rust/soroban/p*/Cargo.lock) Makefile $(RUST_DE
 			;; \
 		esac ; \
 		cd $(abspath $(RUST_BUILD_DIR))/soroban/$$proto && \
-		RUSTFLAGS=-Cmetadata=$$proto \
-		CARGO_NET_GIT_FETCH_WITH_CLI=true cargo build \
+		CC="$(CC)" CXX="$(CXX)" LD="$(LD)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" CXXSTDLIB="$(CXXSTDLIB)" LDFLAGS="$(LDFLAGS)" \
+		RUSTFLAGS="-Cmetadata=$$proto $(RUSTFLAGS_ASAN)" \
+		CARGO_NET_GIT_FETCH_WITH_CLI=true \
+		$(CARGO) build \
 			--package soroban-env-host \
 			--$(RUST_PROFILE) \
 			--locked \
@@ -214,8 +275,12 @@ $(SOROBAN_LIBS_STAMP): $(wildcard rust/soroban/p*/Cargo.lock) Makefile $(RUST_DE
 # them in as separate `--extern` arguments to a slightly-more-manual `cargo
 # rustc` invocation, along with `-L dependency=...` flags to tell cargo where to
 # find indirect deps of those .rlibs.
-$(LIBRUST_STELLAR_CORE): $(RUST_HOST_DEPFILES) $(SRC_RUST_FILES) Makefile $(SOROBAN_LIBS_STAMP)
-	CARGO_NET_GIT_FETCH_WITH_CLI=true cargo rustc \
+$(LIBRUST_STELLAR_CORE): $(RUST_HOST_DEPFILES) $(SRC_RUST_FILES) Makefile $(SOROBAN_LIBS_STAMP) $(RUST_TOOLCHAIN_FILE)
+	rm -rf $(abspath $(RUST_TARGET_DIR))
+	CC="$(CC)" CXX="$(CXX)" LD="$(LD)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" CXXSTDLIB="$(CXXSTDLIB)" LDFLAGS="$(LDFLAGS)" \
+	RUSTFLAGS="$(RUSTFLAGS_ASAN)" \
+	CARGO_NET_GIT_FETCH_WITH_CLI=true \
+	$(CARGO) rustc \
 		--package stellar-core \
 		--$(RUST_PROFILE) \
 		--locked \
@@ -290,7 +355,7 @@ distclean-local: fuzz-clean
 endif # USE_AFL_FUZZ
 
 clean-local:
-	rm -rf $(top_builddir)/target $(top_builddir)/src/rust/soroban/*/target
+	rm -rf $(top_builddir)/target $(top_builddir)/src/rust/soroban/*/target $(RUST_DEP_TREE_STAMP) $(SOROBAN_LIBS_STAMP)
 
 CLEANFILES = $(BUILT_SOURCES) *~ */*~ stellar*.log
 MAINTAINERCLEANFILES = $(srcdir)/Makefile.in $(srcdir)/*~ $(srcdir)/*/*~

src/main/main.cpp

@@ -278,25 +278,7 @@ checkStellarCoreMajorVersionProtocolIdentity()
     }
 }
 
-#ifdef USE_TRACY
-
-std::mutex TRACY_MUTEX;
-static int TRACY_NOT_STARTED = 0;
-static int TRACY_RUNNING = 1;
-static int TRACY_STOPPED = 2;
-static int TRACY_STATE = TRACY_NOT_STARTED;
-
-// Call this only with mutex held
-bool
-tracyEnabled(std::lock_guard<std::mutex> const& _guard)
-{
-    if (TRACY_STATE == TRACY_NOT_STARTED)
-    {
-        stellar::rust_bridge::start_tracy();
-        TRACY_STATE = TRACY_RUNNING;
-    }
-    return TRACY_STATE != TRACY_STOPPED;
-}
+#ifdef USE_TRACY_MEMORY_TRACKING
 
 #ifdef __has_feature
 #if __has_feature(address_sanitizer)
@@ -308,54 +290,42 @@ tracyEnabled(std::lock_guard<std::mutex> const& _guard)
 #endif
 #endif
 
-#ifndef ASAN_ENABLED
+#ifdef ASAN_ENABLED
+#error "ASAN_ENABLED and USE_TRACY_MEMORY_TRACKING are mutually exclusive"
+#else
 void*
 operator new(std::size_t count)
 {
     auto ptr = malloc(count);
-    std::lock_guard<std::mutex> guard(TRACY_MUTEX);
-    if (tracyEnabled(guard))
-    {
-        TracyAlloc(ptr, count);
-    }
+    // "Secure" here means "tolerant of calls outside the
+    // lifeitme of the tracy client".
+    TracySecureAlloc(ptr, count);
     return ptr;
 }
 
 void
 operator delete(void* ptr) noexcept
 {
-    std::lock_guard<std::mutex> guard(TRACY_MUTEX);
-    if (tracyEnabled(guard))
-    {
-        TracyFree(ptr);
-    }
+    TracySecureFree(ptr);
     free(ptr);
 }
 
 void*
 operator new[](std::size_t count)
 {
     auto ptr = malloc(count);
-    std::lock_guard<std::mutex> guard(TRACY_MUTEX);
-    if (tracyEnabled(guard))
-    {
-        TracyAlloc(ptr, count);
-    }
+    TracySecureAlloc(ptr, count);
     return ptr;
 }
 
 void
 operator delete[](void* ptr) noexcept
 {
-    std::lock_guard<std::mutex> guard(TRACY_MUTEX);
-    if (tracyEnabled(guard))
-    {
-        TracyFree(ptr);
-    }
+    TracySecureFree(ptr);
     free(ptr);
 }
-#endif // ASAN_ENABLED
-#endif // USE_TRACY
+#endif // !ASAN_ENABLED
+#endif // USE_TRACY_MEMORY_TRACKING
 
 int
 main(int argc, char* const* argv)
@@ -368,11 +338,6 @@ main(int argc, char* const* argv)
     // At least print a backtrace in any circumstance
     // that would call std::terminate
     std::set_terminate(printBacktraceAndAbort);
-#ifdef USE_TRACY
-    // The rust tracy client library is fussy about trying
-    // to own the tracy startup path.
-    rust_bridge::start_tracy();
-#endif
     Logging::init();
     if (sodium_init() != 0)
     {
@@ -388,12 +353,5 @@ main(int argc, char* const* argv)
     checkXDRFileIdentity();
 
     int res = handleCommandLine(argc, argv);
-#ifdef USE_TRACY
-    {
-        std::lock_guard<std::mutex> guard(TRACY_MUTEX);
-        ___tracy_shutdown_profiler();
-        TRACY_STATE = TRACY_STOPPED;
-    }
-#endif
     return res;
 }

src/rust/Cargo.toml

@@ -30,11 +30,15 @@ itertools = "=0.10.5"
 # There is a table on the README for https://crates.io/crates/tracy-client that
 # maps versions of tracy-client to C++ tracy releases. The lib/tracy submodule
 # of this repo should be pinned out to a matched C++ tracy release version.
+#
+# Also note: this feature list also has to be passed _on the command line_ (i.e.
+# in the Makefile.am) when we separately build the soroban sub-crates because
+# they are separate cargo invocations and do not see this list, or even this
+# file, at all.
 tracy-client = { version = "=0.17.0", features = [
     "enable",
     "ondemand",
     "delayed-init",
-    "manual-lifetime",
     "system-tracing",
     "sampling",
     "code-transfer",