Document Haskell profiling and default to -fprof-auto (digital-asset#…

…1971)
iggy-da · Jul 2, 2019 · c66211d · c66211d
1 parent 2bb9276
commit c66211d
Show file tree

Hide file tree

Showing 5 changed files with 30 additions and 18 deletions.
diff --git a/BAZEL-haskell.md b/BAZEL-haskell.md
@@ -185,22 +185,6 @@ alias(
 )
 ```
 
-## Profiling
-
-To produce a binary with profiling information, you need to pass `-c
-dbg` to Bazel. E.g., `bazel build -c dbg damlc` will build a profiled
-version of `damlc`. Note that by default Bazel won’t automatically add
-cost centres in your code. To get cost centres, you can either add
-[cost centres manually](https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/profiling.html#inserting-cost-centres-by-hand)
-or use one of the
-[options provided by GHC](https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/profiling.html#compiler-options-for-profiling)
-to add them automatically.
-You can either add those options in the `compiler_flags` section of a
-specific target, modify the `da_haskell_library` wrapper in
-`bazel_tools/haskell.bzl` to add a flag to all DAML targets and
-libraries or use it for all targets by modifying the
-`compiler_flags` in the `haskell_toolchain`.
-
 ## Further reading:
 
 - ["Bazel User Guide"](https://github.com/DACH-NY/da/blob/master/BAZEL.md) (DAML specific)

diff --git a/BUILD b/BUILD
@@ -41,6 +41,13 @@ config_setting(
     ],
 )
 
+config_setting(
+    name = "profiling_build",
+    values = {
+        "compilation_mode": "dbg",
+    },
+)
+
 load(
     "@io_tweag_rules_haskell//haskell:c2hs.bzl",
     "c2hs_toolchain",

diff --git a/README.md b/README.md
@@ -111,3 +111,10 @@ from the `.bazelrc` file.
 If you work with multiple copies of this repository, you can point all of them to the same disk cache
 by overwriting these configs in either a `.bazelrc.local` file in each copy, or a `~/.bazelrc` file
 in your home directory.
+
+
+### Haskell profiling builds
+
+To build Haskell executables with profiling enabled, pass `-c dbg` to
+Bazel, e.g. `bazel build -c dbg damlc`. If you want to build the whole
+SDK with profiling enabled use `daml-sdk-head --profiling`.
diff --git a/WORKSPACE b/WORKSPACE
@@ -259,6 +259,10 @@ haskell_register_ghc_nixpkgs(
         "-hide-package=ghc-boot-th",
         "-hide-package=ghc-boot",
     ],
+    compiler_flags_select = {
+        "@com_github_digital_asset_daml//:profiling_build": ["-fprof-auto"],
+        "//conditions:default": [],
+    },
     locale_archive = "@glibc_locales//:locale-archive",
     nix_file = "//nix:bazel.nix",
     nix_file_deps = nix_ghc_deps,

diff --git a/dev-env/bin/daml-sdk-head b/dev-env/bin/daml-sdk-head
@@ -18,19 +18,29 @@ fi
 
 
 NUKE=0
+PROFILING=0
 for opt in "$@" ; do
   case $opt in
     "--nuke")
       NUKE=1
       ;;
+    "--profiling")
+      PROFILING=1
+      ;;
     *)
       echo "Unknown option: $opt"
       echo "Available options:"
       echo "  --nuke  Remove existing daml installation before installing daml-head."
+      echo "  --profiling  Build Haskell executables with profiling enabled."
       exit 1
   esac
 done
 
+BAZEL_MODE_FLAG=""
+
+if [ "$PROFILING" -ne "0" ] ; then
+  BAZEL_MODE_FLAG="-c dbg"
+fi
 
 readonly DAML_HOME="$HOME/.daml"
 if [ -d $DAML_HOME ] && [ "$NUKE" -ne "0" ] ; then
@@ -58,9 +68,9 @@ function cleanup() {
 trap cleanup EXIT
 
 # Building here separately so the user can see the build process which could take a while
-bazel build //release:sdk-head-tarball.tar.gz
+bazel build $BAZEL_MODE_FLAG //release:sdk-head-tarball.tar.gz
 
-readonly TARBALL=$(bazel info bazel-genfiles)/release/sdk-head-tarball.tar.gz
+readonly TARBALL=$(bazel info bazel-genfiles $BAZEL_MODE_FLAG)/release/sdk-head-tarball.tar.gz
 readonly TMPDIR=$(mktemp -d)
 mkdir -p $TMPDIR/sdk-head