0.7.1 --- no loop becomes a C runtime call, at any optimization (#20)

An optimizing compiler replaced wide_length's counting loop with wcslen and a
byte loop in win.cpp with strlen. The C library above is openkal-musl, whose
wchar_t is thirty-two bits, so its wcslen read the command line two units at a
time: every argument of a program built with --release was shortened by a
different amount. -fno-builtin keeps the loops, and the no-C-runtime-symbol
check now builds the release profile as well as dev.

Author: Sunrisepeak

.github/workflows/ci.yml

@@ -433,9 +433,15 @@ jobs:
       # may supply a C runtime of its own; an implementation that reached for
       # this environment's would have its calls resolve to the program's, and
       # the program's would resolve back here.
+      #
+      # ⚠️ IN BOTH PROFILES. An optimizing compiler turns loops into calls ---
+      # a counting loop into `strlen` or `wcslen` --- so objects built without
+      # optimization can hold the property while the ones a release links do not.
       - name: The objects reference no C runtime symbol
         run: |
-          rm -rf target && mcpp build --features standalone --target x86_64-windows-gnu
+          for profile in dev release; do
+          echo "--- profile $profile"
+          rm -rf target && mcpp build --features standalone --target x86_64-windows-gnu --profile "$profile"
           objs="$(find target -path '*/obj/*' -name '*.o' ! -name '*.m.o')"
           test -n "$objs" || { echo "no objects were found; the check would pass vacuously" >&2; exit 1; }
 
@@ -465,7 +471,8 @@ jobs:
             }
           done
           test "$bad" -eq 0
-          echo "the implementation references no C runtime symbol"
+          echo "the implementation references no C runtime symbol ($profile)"
+          done
 
       # A checker is only useful if it fails when it should.
       - name: The independence check detects a dependence

mcpp.toml

@@ -1,7 +1,7 @@
 [package]
 namespace   = "mcpplibs"
 name        = "openkal-windows"
-version     = "0.7.0"
+version     = "0.7.1"
 description = "An implementation of openkal for Windows, written on the Win32 interfaces and the object manager beneath them, using no C runtime symbol."
 license     = "Apache-2.0"
 
@@ -65,7 +65,19 @@ ldflags = ["-lntdll", "-lsynchronization", "-lshell32", "-lkernel32", "-lbcrypt"
 # ABI has a C runtime; there the toolchain's defaults are correct, one of the two
 # toolchains that reach it would not recognise these spellings, and openkal has
 # nothing to say about how a program that has a runtime unwinds.
-cxxflags = ["-fno-exceptions", "-fno-rtti"]
+#
+# ⚠️ AND NO LOOP IS REPLACED BY A CALL, WHICH IS WHAT `-fno-builtin` IS FOR.
+#
+# An optimizing compiler recognises a loop that counts to a terminator and
+# emits a call to the library function that does the same. `wide_length` in
+# src/env.cpp counts sixteen-bit units and became `wcslen`; a byte loop in
+# src/win.cpp became `strlen`. Neither is this environment's: the C library
+# above is openkal-musl, whose `wchar_t` is thirty-two bits, so its `wcslen`
+# read the command line two units at a time and every argument of a program
+# built with `--release` came out shortened by a different amount. The dev
+# profile does not optimize and never showed it, which is also why the check
+# below now builds both profiles.
+cxxflags = ["-fno-exceptions", "-fno-rtti", "-fno-builtin"]
 
 # The other ABI names them in the sources instead --- src/win.cpp for the four
 # above and src/random.cpp for bcrypt --- where its compilers record