lib9, cmd/dist, cmd/5l: embed GOARM into cmd/5l and auto detect GOARM

R=rsc, dave
CC=golang-dev
https://golang.org/cl/6638043

include/libc.h

@@ -293,6 +293,7 @@ extern	char*	getgoos(void);
 extern	char*	getgoarch(void);
 extern	char*	getgoroot(void);
 extern	char*	getgoversion(void);
+extern	char*	getgoarm(void);
 
 #ifdef _WIN32
 

src/cmd/5l/obj.c

@@ -90,7 +90,7 @@ main(int argc, char *argv[])
 	INITENTRY = 0;
 	nuxiinit();
 	
-	p = getenv("GOARM");
+	p = getgoarm();
 	if(p != nil)
 		goarm = atoi(p);
 	else

src/cmd/dist/a.h

@@ -151,3 +151,5 @@ char*	xstrrchr(char*, int);
 char*	xstrstr(char*, char*);
 char*	xworkdir(void);
 int	xsamefile(char*, char*);
+char*	xgetgoarm(void);
+int	xtryexecfunc(void (*)(void));

src/cmd/dist/arm.c

@@ -0,0 +1,45 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "a.h"
+
+#ifndef __ARMEL__
+char *
+xgetgoarm(void)
+{
+	return "6";
+}
+#else
+static void useVFPv3(void);
+static void useVFPv1(void);
+
+char *
+xgetgoarm(void)
+{
+	if(xtryexecfunc(useVFPv3))
+		return "7";
+	else if(xtryexecfunc(useVFPv1))
+		return "6";
+	return "5";
+}
+
+static void
+useVFPv3(void)
+{
+	// try to run VFPv3-only "vmov.f64 d0, #112" instruction
+	// we can't use that instruction directly, because we
+	// might be compiling with a soft-float only toolchain
+	__asm__ __volatile__ (".word 0xeeb70b00");
+}
+
+static void
+useVFPv1(void)
+{
+	// try to run "vmov.f64 d0, d0" instruction
+	// we can't use that instruction directly, because we
+	// might be compiling with a soft-float only toolchain
+	__asm__ __volatile__ (".word 0xeeb00b40");
+}
+
+#endif

src/cmd/dist/build.c

@@ -16,6 +16,7 @@ char *gohostarch;
 char *gohostchar;
 char *gohostos;
 char *goos;
+char *goarm;
 char *goroot = GOROOT_FINAL;
 char *goroot_final = GOROOT_FINAL;
 char *workdir;
@@ -96,6 +97,11 @@ init(void)
 	if(find(goos, okgoos, nelem(okgoos)) < 0)
 		fatal("unknown $GOOS %s", goos);
 
+	xgetenv(&b, "GOARM");
+	if(b.len == 0)
+		bwritestr(&b, xgetgoarm());
+	goarm = btake(&b);
+
 	p = bpathf(&b, "%s/include/u.h", goroot);
 	if(!isfile(p)) {
 		fatal("$GOROOT is not set correctly or not exported\n"
@@ -126,6 +132,7 @@ init(void)
 	xsetenv("GOROOT", goroot);
 	xsetenv("GOARCH", goarch);
 	xsetenv("GOOS", goos);
+	xsetenv("GOARM", goarm);
 
 	// Make the environment more predictable.
 	xsetenv("LANG", "C");
@@ -883,6 +890,7 @@ install(char *dir)
 				bsubst(&b1, "\\", "\\\\");  // turn into C string
 				vadd(&compile, bprintf(&b, "-DGOROOT=\"%s\"", bstr(&b1)));
 				vadd(&compile, bprintf(&b, "-DGOVERSION=\"%s\"", goversion));
+				vadd(&compile, bprintf(&b, "-DGOARM=\"%s\"", goarm));
 			}
 
 			// gc/lex.c records the GOEXPERIMENT setting used during the build.
@@ -1371,6 +1379,8 @@ cmdenv(int argc, char **argv)
 	xprintf(format, "GOHOSTOS", gohostos);
 	xprintf(format, "GOTOOLDIR", tooldir);
 	xprintf(format, "GOCHAR", gochar);
+	if(streq(goarch, "arm"))
+		xprintf(format, "GOARM", goarm);
 
 	if(pflag) {
 		sep = ":";

src/cmd/dist/plan9.c

@@ -749,4 +749,13 @@ xsamefile(char *f1, char *f2)
 	return streq(f1, f2); // suffice for now
 }
 
+// xtryexecfunc tries to execute function f, if any illegal instruction
+// signal received in the course of executing that function, it will
+// return 0, otherwise it will return 1.
+int
+xtryexecfunc(void (*f)(void))
+{
+	return 0; // suffice for now
+}
+
 #endif // PLAN9

src/cmd/dist/unix.c

@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <stdarg.h>
+#include <setjmp.h>
 
 // bprintf replaces the buffer with the result of the printf formatting
 // and returns a pointer to the NUL-terminated buffer contents.
@@ -734,5 +735,31 @@ xsamefile(char *f1, char *f2)
 	return streq(f1, f2); // suffice for now
 }
 
+sigjmp_buf sigill_jmpbuf;
+static void sigillhand(int);
+// xtryexecfunc tries to execute function f, if any illegal instruction
+// signal received in the course of executing that function, it will
+// return 0, otherwise it will return 1.
+int
+xtryexecfunc(void (*f)(void))
+{
+	int r;
+	r = 0;
+	signal(SIGILL, sigillhand);
+	if(sigsetjmp(sigill_jmpbuf, 1) == 0) {
+		f();
+		r = 1;
+	}
+	signal(SIGILL, SIG_DFL);
+	return r;
+}
+// SIGILL handler helper
+static void
+sigillhand(int signum)
+{
+	USED(signum);
+	siglongjmp(sigill_jmpbuf, 1);
+}
+
 #endif // PLAN9
 #endif // __WINDOWS__

src/cmd/dist/windows.c

@@ -962,4 +962,13 @@ xsamefile(char *f1, char *f2)
 	return 0;
 }
 
+// xtryexecfunc tries to execute function f, if any illegal instruction
+// signal received in the course of executing that function, it will
+// return 0, otherwise it will return 1.
+int
+xtryexecfunc(void (*f)(void))
+{
+	return 0; // suffice for now
+}
+
 #endif // __WINDOWS__

src/lib9/goos.c

@@ -39,3 +39,9 @@ getgoversion(void)
 {
 	return GOVERSION;
 }
+
+char*
+getgoarm(void)
+{
+	return defgetenv("GOARM", GOARM);
+}

src/make.bat

@@ -60,7 +60,7 @@ echo # Building C bootstrap tool.
 echo cmd/dist
 if not exist ..\bin\tool mkdir ..\bin\tool
 :: Windows has no glob expansion, so spell out cmd/dist/*.c.
-gcc -O2 -Wall -Werror -o cmd/dist/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c
+gcc -O2 -Wall -Werror -o cmd/dist/dist.exe -Icmd/dist %DEFGOROOT% cmd/dist/buf.c cmd/dist/build.c cmd/dist/buildgc.c cmd/dist/buildruntime.c cmd/dist/goc2c.c cmd/dist/main.c cmd/dist/windows.c cmd/dist/arm.c
 if errorlevel 1 goto fail
 .\cmd\dist\dist env -wp >env.bat
 if errorlevel 1 goto fail