Tracy: autotools setup

Well, this was as painful as expected.

Introducing a proper autotool-based tracy build. I don't think this is
the right approach, but hey, it works.

Tracy is not distributing any pkg-config file, so we had to fallback
to a more "manual" method to propagate the headers path. Instead of
having a plain enable/disable flag, we send the path to the tracy
/public subfolder (~= $out in the Tracy Nix derivation).

The flake Nixpkgs is currently pointing to 23.05. The tracy derivation
was only building the visualizer, not the client library back then. We
introduce a 23.11 Nixpkgs and build its Tracy derivation with the
23.05 toolchain to go around some glibc ABI incompatibilities.

Kudos to Mic92 for the help for the flake bit.

Co-authored-by: Jörg Thalheim <joerg@thalheim.io>

Makefile.config.in

@@ -14,6 +14,7 @@ ENABLE_FUNCTIONAL_TESTS = @ENABLE_FUNCTIONAL_TESTS@
 ENABLE_INTERNAL_API_DOCS = @ENABLE_INTERNAL_API_DOCS@
 ENABLE_S3 = @ENABLE_S3@
 ENABLE_UNIT_TESTS = @ENABLE_UNIT_TESTS@
+ENABLE_TRACY = @ENABLE_TRACY@
 GTEST_LIBS = @GTEST_LIBS@
 HAVE_LIBCPUID = @HAVE_LIBCPUID@
 HAVE_SECCOMP = @HAVE_SECCOMP@

configure.ac

@@ -348,6 +348,15 @@ if test "$gc" = yes; then
   AC_DEFINE(HAVE_BOEHMGC, 1, [Whether to use the Boehm garbage collector.])
 fi
 
+AC_ARG_ENABLE(tracy-profiler, AS_HELP_STRING([--enable-tracy-profiler],[Profile the Nix evaluation using the Tracy profiler (default no)]),
+  TRACY_PROFILER=$enableval, TRACY_PROFILER=no)
+if test "$TRACY_PROFILER" != no; then
+  # We don't have any pkg-config file for tracy, we have to inject the
+  # headers manually…
+  CXXFLAGS="-I $TRACY_PROFILER/include/Tracy $CXXFLAGS"
+fi
+AC_SUBST(TRACY_PROFILER)
+
 AS_IF([test "$ENABLE_UNIT_TESTS" == "yes"],[
 
 # Look for gtest.

flake.lock

@@ -64,12 +64,29 @@
         "type": "github"
       }
     },
+    "nixpkgs-tracy": {
+      "locked": {
+        "lastModified": 1707205788,
+        "narHash": "sha256-dFPctGYh7cNPAuJQY9i4+1/M+LdrRDpk0RRwpClEQ4w=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e311f423a6e56505afae9d4b621759826e7270c0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-23.11-small",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-compat": "flake-compat",
         "libgit2": "libgit2",
         "nixpkgs": "nixpkgs",
-        "nixpkgs-regression": "nixpkgs-regression"
+        "nixpkgs-regression": "nixpkgs-regression",
+        "nixpkgs-tracy": "nixpkgs-tracy"
       }
     }
   },

flake.nix

@@ -2,11 +2,14 @@
   description = "The purely functional package manager";
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05-small";
+  # Tracy is in a half-broken situation on 23.05. We need the changes
+  # introduced by https://github.com/NixOS/nixpkgs/pull/261589.
+  inputs.nixpkgs-tracy.url = "github:NixOS/nixpkgs/nixos-23.11-small";
   inputs.nixpkgs-regression.url = "github:NixOS/nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2";
   inputs.flake-compat = { url = "github:edolstra/flake-compat"; flake = false; };
   inputs.libgit2 = { url = "github:libgit2/libgit2"; flake = false; };
 
-  outputs = { self, nixpkgs, nixpkgs-regression, libgit2, ... }:
+  outputs = { self, nixpkgs, nixpkgs-regression, libgit2, nixpkgs-tracy, ... }:
 
     let
       inherit (nixpkgs) lib;
@@ -186,6 +189,14 @@
                 stdenv
                 versionSuffix
                 ;
+              # We have to use the nixos-23.11 tracy version. However,
+              # we can't link the 23.11 lib on our 23.05 nix without
+              # hitting some Glibc ABI incompatibilities.
+              #
+              # To go around that issue, we build the 23.11 tracy
+              # derivation with the 23.05 toolchain/libs.
+              tracy = final.callPackage (nixpkgs-tracy.legacyPackages.${final.hostPlatform.system}.path + "/pkgs/development/tools/tracy") {};
+              enableTracy = true;
               officialRelease = false;
               boehmgc = final.boehmgc-nix;
               libgit2 = final.libgit2-nix;
@@ -223,6 +234,10 @@
           self.packages.${system}.nix.override { enableGC = false; }
         );
 
+        buildWithTracy = forAllSystems (system:
+          self.packages.${system}.nix.override { enableTracy = true; }
+        );
+
         buildNoTests = forAllSystems (system:
           self.packages.${system}.nix.override {
             doCheck = false;
@@ -394,7 +409,7 @@
           stdenvs)));
 
       devShells = let
-        makeShell = pkgs: stdenv: (pkgs.nix.override { inherit stdenv; forDevShell = true; }).overrideAttrs (attrs: {
+        makeShell = pkgs: stdenv: (pkgs.nix.override { inherit stdenv; forDevShell = true; enableTracy = true; }).overrideAttrs (attrs: {
           installFlags = "sysconfdir=$(out)/etc";
           shellHook = ''
             PATH=$prefix/bin:$PATH

package.nix

@@ -34,6 +34,7 @@
 , rapidcheck
 , sqlite
 , util-linux
+, tracy
 , xz
 
 , busybox-sandbox-shell ? null
@@ -76,6 +77,9 @@
 # only leaked *within* the process.)
 , enableGC ? true
 
+# TODO
+, enableTracy ? false
+
 # Whether to enable Markdown rendering in the Nix binary.
 , enableMarkdown ? !stdenv.hostPlatform.isWindows
 
@@ -234,6 +238,7 @@ in {
     rapidcheck
   ] ++ lib.optional stdenv.isLinux libseccomp
     ++ lib.optional stdenv.hostPlatform.isx86_64 libcpuid
+    ++ lib.optional enableTracy tracy
     # There have been issues building these dependencies
     ++ lib.optional (stdenv.hostPlatform == stdenv.buildPlatform && (stdenv.isLinux || stdenv.isDarwin))
       (aws-sdk-cpp.override {
@@ -287,6 +292,8 @@ in {
     (lib.enableFeature enableMarkdown "markdown")
     (lib.enableFeature installUnitTests "install-unit-tests")
     (lib.withFeatureAs true "readline-flavor" readlineFlavor)
+  ] ++ lib.optionals (enableTracy) [
+    "--enable-tracy-profiler=${tracy}"
   ] ++ lib.optionals (!forDevShell) [
     "--sysconfdir=/etc"
   ] ++ lib.optionals installUnitTests [

src/libexpr/local.mk

@@ -10,10 +10,9 @@ libexpr_SOURCES := \
   $(wildcard $(d)/primops/*.cc) \
   $(wildcard $(d)/flake/*.cc) \
   $(d)/lexer-tab.cc \
-  $(d)/parser-tab.cc \
-  $(d)/tracy/public/TracyClient.cpp
+  $(d)/parser-tab.cc
 
-libexpr_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/libmain -I src/libexpr -I src/libexpr/tracy/public -DTRACY_ENABLE=1
+libexpr_CXXFLAGS += -I src/libutil -I src/libstore -I src/libfetchers -I src/libmain -I src/libexpr
 
 libexpr_LIBS = libutil libstore libfetchers