Replace config.def.h with a configure script

6 files changed, 196 insertions, 93 deletions

diff --git a/.builds/alpine.yml b/.builds/alpine.yml
index 71ed175..df36db3 100644
--- a/.builds/alpine.yml
+++ b/.builds/alpine.yml
@@ -1,9 +1,12 @@
 image: alpine/edge
 sources:
-  - https://git.sr.ht/~mcf/cc
-  - git://c9x.me/qbe.git
+- https://git.sr.ht/~mcf/cc
+- git://c9x.me/qbe.git
+environment:
+  PATH: $HOME/qbe/obj:$PATH
 tasks:
-  - build: |
-      make -C qbe
-      echo 'CFLAGS=-DDYNAMICLINKER=\"/lib/ld-musl-x86_64.so.1\"' >cc/config.mk
-      PATH=$PWD/qbe/obj:$PATH make -C cc all check bootstrap
+- build: |
+    make -C qbe
+    cd cc
+    ./configure
+    make all check bootstrap
diff --git a/.builds/debian.yml b/.builds/debian.yml
index bcba5fc..ac0eb97 100644
--- a/.builds/debian.yml
+++ b/.builds/debian.yml
@@ -1,8 +1,12 @@
 image: debian/stretch
 sources:
-  - https://git.sr.ht/~mcf/cc
-  - git://c9x.me/qbe.git
+- https://git.sr.ht/~mcf/cc
+- git://c9x.me/qbe.git
+environment:
+  PATH: $HOME/qbe/obj:$PATH
 tasks:
-  - build: |
-      make -C qbe
-      PATH=$PWD/qbe/obj:$PATH make -C cc all check bootstrap
+- build: |
+    make -C qbe
+    cd cc
+    ./configure
+    make all check bootstrap
diff --git a/.builds/freebsd.yml b/.builds/freebsd.yml
index 8eb359d..280081a 100644
--- a/.builds/freebsd.yml
+++ b/.builds/freebsd.yml
@@ -1,33 +1,14 @@
 image: freebsd/latest
 sources:
-  - https://git.sr.ht/~mcf/cc
-  - git://c9x.me/qbe.git
+- https://git.sr.ht/~mcf/cc
+- git://c9x.me/qbe.git
 packages:
-  - gmake
+- gmake
+environment:
+  PATH: $HOME/qbe/obj:$PATH
 tasks:
-  - build: |
-      gmake -C qbe
-      cd cc
-      cat >config.h <<EOF
-      static char *startfiles[] = {"-l", ":crt1.o", "-l", ":crti.o"};
-      static char *endfiles[] = {"-l", ":crtn.o", "-l", "c"};
-      static char *preprocesscmd[] = {
-      	"cpp", "-P",
-      	"-U", "__GNUC__", "-D", "__GNUC__=3",
-      	"-U", "__GNUC_MINOR__", "-D", "__GNUC_MINOR__=3",
-      	"-D", "__asm(x)=",
-      	"-D", "__attribute__(x)=",
-      	"-D", "__inline=",
-      	"-D", "_Pragma(x)=",
-      	"-D", "_Nullable=",
-      	"-D", "_Nonnull=",
-      	"-D", "_XLOCALE_INLINE=static inline",
-      	"-D", "__NO_TLS",
-      };
-      static char *compilecmd[] = {"cc-qbe"};
-      static char *codegencmd[] = {"qbe"};
-      static char *assemblecmd[] = {"as"};
-      static char *linkcmd[] = {"ld", "-L", "/usr/lib", "--dynamic-linker", "/libexec/ld-elf.so.1"};
-      EOF
-      echo 'CFLAGS=-Wno-parentheses -Wno-switch' >config.mk
-      PATH=$HOME/qbe/obj:$PATH make all check bootstrap
+- build: |
+    gmake -C qbe
+    cd cc
+    ./configure
+    make all check bootstrap
diff --git a/README.md b/README.md
index 693d13f..0e87989 100644
--- a/README.md
+++ b/README.md
@@ -27,10 +27,20 @@ one is currently required as well.
 
 ## Building
 
-You will need to create a `config.h` appropriate for the target system. If
-missing, a default version will be created from `config.def.h`,
-which should work for most glibc systems, or musl systems with
-`-D 'DYNAMICLINKER="/lib/ld-musl-x86_64.so.1"'`.
+Run `./configure` to create a `config.h` and `config.mk` appropriate for
+your system. If your system is not supported by the configure script,
+you can create these files manually. `config.h` should define several
+string arrays (`static char *[]`):
+
+- **`startfiles`**: Objects to pass to the linker at the beginning of
+  the link command.
+- **`endfiles`**: Objects to pass to the linker at the end of the link
+  command (including libc).
+- **`preprocesscmd`**: The preprocessor command, and any necessary flags
+  for the target system.
+- **`codegencmd`**: The QBE command, and possibly explicit target flags.
+- **`assemblecmd`**: The assembler command.
+- **`linkcmd`**: The linker command.
 
 You may also want to customize your environment or `config.mk` with the
 appropriate `CC`, `CFLAGS` and `LDFLAGS`.
diff --git a/config.def.h b/config.def.h
deleted file mode 100644
index 2c87cdd..0000000
--- a/config.def.h
+++ /dev/null
@@ -1,49 +0,0 @@
-#ifndef DYNAMICLINKER
-#define DYNAMICLINKER "/lib64/ld-linux-x86-64.so.2"
-#endif
-
-/*
-glibc systems might need crtbegin.o at the end of `startfiles` and
-crtend.o at the beginning of `endfiles`. These are provided by gcc and
-not usually in the linker's default search path, so we just leave it to
-the user to configure as needed.
-*/
-
-static char *startfiles[] = {
-	"-l", ":crt1.o",
-	"-l", ":crti.o",
-};
-static char *endfiles[] = {
-	"-l", ":crtn.o",
-	"-l", "c",
-};
-
-static char *preprocesscmd[] = {
-	"cpp", "-P",
-
-	/* we don't yet support these optional features */
-	"-D", "__STDC_NO_ATOMICS__",
-	"-D", "__STDC_NO_COMPLEX__",
-	"-D", "__STDC_NO_VLA__",
-
-	/* specify the GNU C extensions we support */
-	"-U", "__GNUC__", "-D", "__GNUC__=1",
-	"-U", "__GNUC_MINOR__", "-D", "__GNUC_MINOR__=0",
-
-	/* prevent glibc from using statement expressions for assert */
-	"-D", "__STRICT_ANSI__",
-
-	/* ignore attributes and extension markers */
-	"-D", "__attribute__(x)=",
-	"-D", "__extension__=",
-
-	/* alternate keywords */
-	"-D", "__alignof__=_Alignof",
-	"-D", "__inline=inline",
-	"-D", "__inline__=inline",
-	"-D", "__signed__=signed",
-	"-D", "__thread=_Thread_local",
-};
-static char *codegencmd[] = {"qbe"};
-static char *assemblecmd[] = {"as"};
-static char *linkcmd[] = {"ld", "--dynamic-linker=" DYNAMICLINKER};
diff --git a/configure b/configure
new file mode 100755
index 0000000..5a1165a
--- /dev/null
+++ b/configure
@@ -0,0 +1,154 @@
+#!/bin/sh
+
+fail() {
+	echo "$0: $*" >&2
+	exit 1
+}
+
+host=
+target=
+gcclibdir=
+
+for arg ; do
+	case "$arg" in
+	--host=*) host=${arg#*=} ;;
+	--target=*) target=${arg#*=} ;;
+	--with-cpp=*) DEFAULT_PREPROCESSOR=${arg#*=} ;;
+	--with-qbe=*) DEFAULT_QBE=${arg#*=} ;;
+	--with-as=*) DEFAULT_ASSEMBLER=${arg#*=} ;;
+	--with-ld=*) DEFAULT_LINKER=${arg#*=} ;;
+	--with-gcc-libdir=*) gcclibdir=${arg#*=} ;;
+	CC=*) CC=${arg#*=} ;;
+	CFLAGS=*) CFLAGS=${arg#*=} ;;
+	LDFLAGS=*) LDFLAGS=${arg#*=} ;;
+	*) fail "unknown option '$arg'"
+	esac
+done
+
+: ${CC:=cc}
+: ${DEFAULT_PREPROCESSOR:=cpp}
+: ${DEFAULT_QBE:=qbe}
+: ${DEFAULT_ASSEMBLER:=as}
+: ${DEFAULT_LINKER:=ld}
+
+printf 'checking host system type... '
+test -n "$host" || host=$($CC -dumpmachine 2>/dev/null) || fail "could not determine host"
+printf '%s\n' "$host"
+
+printf 'checking target system type...'
+test -n "$target" || target=$host
+printf '%s\n' "$target"
+
+case "$target" in
+x86_64*|amd64*) qbetarget=amd64_sysv ;;
+aarch64*)       qbetarget=arm64      ;;
+*) fail "unsupported architecture '${target%%-*}'"
+esac
+
+gnuc='
+	/* specify the GNU C extensions we support */
+	"-D", "__GNUC__=1",
+	"-D", "__GNUC_MINOR__=0",
+'
+
+case "$target" in
+*-linux-*musl*)
+	case "$target" in
+	x86_64*)  dynamiclinker=/lib/ld-musl-x86_64.so.1  ;;
+	aarch64*) dynamiclinker=/lib/ld-musl-aarch64.so.1 ;;
+	*) fail "unsuported target '$target'"
+	esac
+	startfiles='"-l", ":crt1.o", "-l", ":crti.o"'
+	endfiles='"-l", ":crtn.o", "-l", "c"'
+	;;
+*-linux-*gnu*)
+	case "$target" in
+	x86_64*)  dynamiclinker=/lib64/ld-linux-x86-64.so.2 ;;
+	aarch64*) dynamiclinker=/lib/ld-linux-aarch64.so.1  ;;
+	*) fail "unsuported target '$target'"
+	esac
+	startfiles='"-l", ":crt1.o", "-l", ":crti.o", "-l", ":crtbegin.o"'
+	endfiles='"-l", ":crtend.o", "-l", ":crtn.o", "-l", "c"'
+	if [ -z "$gcclibdir" ] ; then
+		test "$host" = "$target" || fail "gcc libdir must be specified when building a cross-compiler"
+		crtbegin=$($CC -print-file-name=crtbegin.o 2>/dev/null)
+		gcclibdir=${crtbegin%/*}
+	fi
+	linkflags='"-L", "'$gcclibdir'"',
+	defines='
+	/* prevent glibc from using statement expressions for assert */
+	"-D", "__STRICT_ANSI__",
+'
+	;;
+*-*freebsd*)
+	dynamiclinker=/libexec/ld-elf.so.1
+	startfiles='"-l", ":crt1.o", "-l", ":crti.o"'
+	endfiles='"-l", ":crtn.o", "-l", "c"'
+	# any value of __GNUC__ will cause FreeBSD's headers to use asm for bswap
+	gnuc=
+	linkflags='"-L", "/usr/lib"',
+	defines='
+	"-D", "_Pragma(x)=",
+	"-D", "_Nullable=",
+	"-D", "_Nonnull=",
+
+	"-D", "__GNUCLIKE_BUILTIN_STDARG",
+	"-D", "__GNUCLIKE_BUILTIN_VARARGS",
+
+	/* required to define _RuneLocale, needed by xlocale/_ctype.h */
+	"-D", "_USE_CTYPE_INLINE_",
+	/* workaround for #42 */
+	"-D", "_XLOCALE_INLINE=static inline",
+	/* used like attribute after declarator, so _Alignas will not work here */
+	"-D", "__aligned(x)=",
+	/* TLS is not yet supported (#8) */
+	"-D", "__NO_TLS",
+
+	/* disable warnings for redefining _Pragma */
+	"-Wno-builtin-macro-redefined",
+'
+	;;
+*)
+	fail "unknown target '$target', please create config.h manually"
+esac
+
+printf "creating config.h... "
+cat >config.h <<EOF
+static char *startfiles[]    = {$startfiles};
+static char *endfiles[]      = {$endfiles};
+static char *preprocesscmd[] = {
+	"$DEFAULT_PREPROCESSOR", "-P", "-std=c11",
+
+	/* clear preprocessor GNU C version */
+	"-U", "__GNUC__",
+	"-U", "__GNUC_MINOR__",
+
+	/* we don't yet support these optional features */
+	"-D", "__STDC_NO_ATOMICS__",
+	"-D", "__STDC_NO_COMPLEX__",
+	"-D", "__STDC_NO_VLA__",
+
+	/* ignore attributes and extension markers */
+	"-D", "__attribute__(x)=",
+	"-D", "__extension__=",
+
+	/* alternate keywords */
+	"-D", "__alignof__=_Alignof",
+	"-D", "__inline=inline",
+	"-D", "__inline__=inline",
+	"-D", "__signed__=signed",
+	"-D", "__thread=_Thread_local",
+$gnuc$defines};
+static char *codegencmd[]    = {"$DEFAULT_QBE", "-t", "$qbetarget"};
+static char *assemblecmd[]   = {"$DEFAULT_ASSEMBLER"};
+static char *linkcmd[]       = {"$DEFAULT_LINKER", "--dynamic-linker", "$dynamiclinker", $linkflags};
+EOF
+echo done
+
+printf "creating config.mk... "
+cat >config.mk <<EOF
+CC=${CC:-cc}
+CFLAGS=${CFLAGS:--std=c11 -Wall -Wno-parentheses -Wno-switch -g -pipe}
+LDFLAGS=$LDFLAGS
+EOF
+echo done