Refactor the way arguments are passed in bazel, add -flto

This adds a macro "vere_library" which supports our concepts of debug and
release builds, and gives finer-grained control over which copts/linkopts are
passed and when.

Takes advantage of bazel's "compilation_mode={dbg,opt}" to control
debug/optimized builds.

.bazelrc

@@ -20,19 +20,21 @@ build --@io_bazel_rules_docker//transitions:enable=false
 build --flag_alias=clang_version=//:clang_version
 build --flag_alias=gcc_version=//:gcc_version
 
+# Use optimized build by default. According to the bazel documentation, this
+# corresponds to -O2 -DNDEBUG, but these are overriden in
+# //bazel/common_settings.bzl:vere_library.
+# https://bazel.build/docs/user-manual#build-semantics
+build --compilation_mode=opt
+
 # Don't include source level debug info on macOS. See
 # https://github.com/urbit/urbit/issues/5561 and
 # https://github.com/urbit/vere/issues/131.
-build:linux --per_file_copt='pkg/.*@-g'
 build:linux --host_copt='-g'
 build --strip=never
 
-# Use -O3 as the default optimization level.
-build --per_file_copt='pkg/.*@-O3'
+# Turn on optimization, CPU and memory debug for exec config, which we only use
+# to run the fake ship tests.  Also turn on extra snapshot validation.
 build --host_copt='-O3'
-
-# Turn on CPU and memory debug for exec config, which we only use to run the
-# fake ship tests.  Also turn on extra snapshot validation.
 build --host_copt='-DU3_CPU_DEBUG'
 build --host_copt='-DU3_MEMORY_DEBUG'
 build --host_copt='-DC3DBG'
@@ -45,12 +47,5 @@ build:mem_dbg --per_file_copt='pkg/.*@-DU3_MEMORY_DEBUG'
 build:cpu_dbg --per_file_copt='pkg/.*@-DU3_CPU_DEBUG'
 build:snp_dbg --per_file_copt='pkg/.*@-DU3_SNAPSHOT_VALIDATION'
 
-# Enable maximum debug info and disable optimizations for debug config. It's
-# important that these lines come after setting the default debug and
-# optimization level flags above.
-build:dbg --per_file_copt='pkg/.*@-O0'
-build:dbg --per_file_copt='pkg/.*@-g3'
-build:dbg --per_file_copt='pkg/.*@-DC3DBG'
-
 # Any personal configuration should go in .user.bazelrc.
 try-import %workspace%/.user.bazelrc

BUILD.bazel

@@ -37,6 +37,38 @@ config_setting(
     ],
 )
 
+#
+# CONFIGS DETAILING WHEN TO ENABLE CERTAIN FEATURES BY DEFAULT.
+# CHANGES BEHAVIOR OF //bazel/common_settings.bzl:vere_library.
+#
+
+config_setting(
+    name = "thinlto",
+    constraint_values = [
+        "@platforms//os:macos",
+    ],
+    values = {
+        "compilation_mode": "opt"
+    }
+)
+
+config_setting(
+    name = "lto",
+    constraint_values = [
+        "@platforms//os:linux",
+    ],
+    values = {
+        "compilation_mode": "opt"
+    }
+)
+
+config_setting(
+    name = "debug",
+    values = {
+        "compilation_mode": "dbg"
+    }
+)
+
 #
 # COMPILERS
 #

bazel/common_settings.bzl

@@ -10,3 +10,50 @@ string_flag = rule(
     build_setting = config.string(flag = True),
     doc = "A string-typed build setting that can be set on the command line",
 )
+
+def vere_library(copts = [], linkopts = [], **kwargs):
+  native.cc_library(
+    copts = copts + select({
+        "//:debug": ["-O0", "-g3", "-DC3DBG"],
+        "//conditions:default": ["-O3"]
+    }) + select({
+        "//:lto": ['-flto'],
+        "//:thinlto": ['-flto=thin'],
+        "//conditions:default": []
+    }) + select({
+        # Don't include source level debug info on macOS. See
+        # https://github.com/urbit/urbit/issues/5561 and
+        # https://github.com/urbit/vere/issues/131.
+        "//:debug": [],
+        "@platforms//os:linux": ["-g"],
+        "//conditions:default": [],
+    }),
+    linkopts = linkopts + ['-g'] + select({
+        "//:lto": ['-flto'],
+        "//:thinlto": ['-flto=thin'],
+        "//conditions:default": []
+    }),
+    **kwargs,
+  )
+
+def vere_binary(copts = [], linkopts = [], **kwargs):
+  native.cc_binary(
+    copts = copts + select({
+        "//:debug": ["-O0", "-g3", "-DC3DBG"],
+        "//conditions:default": ["-O3"]
+    }) + select({
+        "//:lto": ['-flto'],
+        "//:thinlto": ['-flto=thin'],
+        "//conditions:default": []
+    }) + select({
+        "//:debug": [],
+        "@platforms//os:linux": ["-g"],
+        "//conditions:default": [],
+    }),
+    linkopts = linkopts + ['-g'] + select({
+        "//:lto": ['-flto'],
+        "//:thinlto": ['-flto=thin'],
+        "//conditions:default": []
+    }),
+    **kwargs,
+  )

pkg/c3/BUILD.bazel

@@ -2,7 +2,9 @@
 # LIBRARIES
 #
 
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "c3",
     srcs = glob(
         [

pkg/ent/BUILD.bazel

@@ -2,7 +2,9 @@
 # LIBRARIES
 #
 
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "ent",
     srcs = ["ent.c"],
     hdrs = ["ent.h"],

pkg/noun/BUILD.bazel

@@ -2,7 +2,9 @@
 # LIBRARIES
 #
 
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "noun",
     srcs = glob(
         [

pkg/ur/BUILD.bazel

@@ -2,7 +2,9 @@
 # LIBRARIES
 #
 
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "ur",
     srcs = [
         "bitstream.c",

pkg/urcrypt/BUILD.bazel

@@ -2,7 +2,9 @@
 # LIBRARIES
 #
 
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "urcrypt",
     srcs = glob(
         [

pkg/urcrypt/ge-additions/BUILD.bazel

@@ -1,4 +1,6 @@
-cc_library(
+load("//bazel:common_settings.bzl", "vere_library")
+
+vere_library(
     name = "ge-additions",
     srcs = ["ge-additions.c"],
     hdrs = ["ge-additions.h"],

pkg/vere/BUILD.bazel

@@ -2,6 +2,8 @@
 # GENERATED FILES
 #
 
+load("//bazel:common_settings.bzl", "vere_library", "vere_binary")
+
 # An approximation of `xxd -i` that runs on all platforms where Bash is
 # present. Generates a `.h` file that declares the array and array length as
 # `extern` global variables and a `.c` file containing the array and array
@@ -86,7 +88,7 @@ genrule(
 # LIBRARIES
 #
 
-cc_library(
+vere_library(
     name = "vere",
     srcs = glob(
         [
@@ -138,7 +140,7 @@ cc_library(
 # BINARIES
 #
 
-cc_binary(
+vere_binary(
     name = "urbit",
     srcs = [
         "main.c",