Use better test for usable compiler in ld testsuite.

The ld testsuite includes numerous tests that depend on being able to
compile and link programs with the C compiler.  Some of these tests
use [which $CC] to check for the presence of the compiler before
proceeding with the test, but run_ld_link_exec_tests and run_cc_link_tests
give ERRORs if compilation fails.  Also, even if $CC is defined and present,
it may not be usable due to missing libraries, etc.

This patch adds a new procedure check_compiler_available that attempts
to build an empty program and caches the result.  Uses of [which $CC]
are replaced with calls to this procedure, and run_ld_link_exec_tests
and run_cc_link_tests now also guard attempts to use $CC.

2019-04-24  Sandra Loosemore  <sandra@codesourcery.com>

	ld/
	* testsuite/config/default.exp: Use [check_compiler_available]
	instead of [which $CC].
	* testsuite/ld-auto-import/auto-import.exp: Likewise.
	* testsuite/ld-cygwin/exe-export.exp: Likewise.
	* testsuite/ld-elf/audit.exp: Likewise.
	* testsuite/ld-elf/compress.exp: Likewise.
	* testsuite/ld-elf/dwarf.exp: Likewise.
	* testsuite/ld-elf/elf.exp: Likewise.
	* testsuite/ld-elf/indirect.exp: Likewise.
	* testsuite/ld-elf/linux-x86.exp: Likewise.
	* testsuite/ld-elf/shared.exp: Likewise.
	* testsuite/ld-elf/tls.exp: Likewise.
	* testsuite/ld-elf/wrap.exp: Likewise.
	* testsuite/ld-elfcomm/elfcomm.exp: Likewise.
	* testsuite/ld-elfvers/vers.exp: Likewise.
	* testsuite/ld-elfvsb/elfvsb.exp: Likewise.
	* testsuite/ld-elfweak/elfweak.exp: Likewise.
	* testsuite/ld-gc/gc.exp: Likewise.
	* testsuite/ld-i386/i386.exp: Likewise.
	* testsuite/ld-i386/no-plt.exp: Likewise.
	* testsuite/ld-i386/tls.exp: Likewise.
	* testsuite/ld-ifunc/ifunc.exp: Likewise.
	* testsuite/ld-mn10300/mn10300.exp: Likewise.
	* testsuite/ld-pe/pe-compile.exp: Likewise.
	* testsuite/ld-pe/pe-run.exp: Likewise.
	* testsuite/ld-pe/pe-run2.exp: Likewise.
	* testsuite/ld-pie/pie.exp: Likewise.
	* testsuite/ld-plugin/lto.exp: Likewise.
	* testsuite/ld-plugin/plugin.exp: Likewise.
	* testsuite/ld-scripts/crossref.exp: Likewise.
	* testsuite/ld-sh/sh.exp: Likewise.
	* testsuite/ld-shared/shared.exp: Likewise.
	* testsuite/ld-size/size.exp: Likewise.
	* testsuite/ld-srec/srec.exp: Likewise.
	* testsuite/ld-undefined/undefined.exp: Likewise.
	* testsuite/ld-unique/unique.exp: Likewise.
	* testsuite/ld-x86-64/mpx.exp: Likewise.
	* testsuite/ld-x86-64/no-plt.exp: Likewise.
	* testsuite/ld-x86-64/tls.exp: Likewise.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/lib/ld-lib.exp (run_ld_link_exec_tests): Call
	check_compiler_available before trying to use the compiler.
	(run_cc_link_tests): Likewise.
	(check_compiler_available): New.  Use it instead of [which $CC].

1 files changed, 57 insertions, 4 deletions

diff --git a/ld/testsuite/lib/ld-lib.exp b/ld/testsuite/lib/ld-lib.exp
index dc55dc8..0ff51c9 100644
--- a/ld/testsuite/lib/ld-lib.exp
+++ b/ld/testsuite/lib/ld-lib.exp
@@ -688,6 +688,11 @@ proc run_ld_link_exec_tests { ldtests args } {
 	set objfiles {}
 	set failed 0
 
+	if { ![check_compiler_available] } {
+	    unsupported $testname
+	    continue
+	}
+
 #	verbose -log "Testname is $testname"
 #	verbose -log "ld_options is $ld_options"
 #	verbose -log "as_options is $as_options"
@@ -840,6 +845,11 @@ proc run_cc_link_tests { ldtests } {
 	set check_ld(terminal) 0
 	set check_ld(source) ""
 
+	if { ![check_compiler_available] } {
+	    unsupported $testname
+	    continue
+	}
+
 	#verbose -log "testname  is $testname"
 	#verbose -log "ldflags   is $ldflags"
 	#verbose -log "cflags    is $cflags"
@@ -1140,6 +1150,49 @@ proc check_sysroot_available { } {
     return $ld_sysroot_available_saved
 }
 
+# Return true if we can build a program with the compiler.
+# On some targets, CC might be defined, but libraries and startup
+# code might be missing or require special options that the ld test
+# harness doesn't know about.
+
+proc check_compiler_available { } {
+    global compiler_available_saved
+    global CC
+
+    if {![info exists compiler_available_saved]} {
+        if { [which $CC] == 0 } {
+	    set compiler_available_saved 0
+	    return 0
+	}
+
+	set flags ""
+	if [board_info [target_info name] exists cflags] {
+	    append flags " [board_info [target_info name] cflags]"
+	}
+	if [board_info [target_info name] exists ldflags] {
+	    append flags " [board_info [target_info name] ldflags]"
+	}
+
+	set basename "tmpdir/compiler[pid]"
+	set src ${basename}.c
+	set output ${basename}.out
+	set f [open $src "w"]
+	puts $f "int main (void)"
+	puts $f "{"
+	puts $f "  return 0; "
+	puts $f "}"
+	close $f
+	if [is_remote host] {
+	    set src [remote_download host $src]
+	}
+	set compiler_available_saved [run_host_cmd_yesno "$CC" "$flags $src -o $output"]
+	remote_file host delete $src
+	remote_file host delete $output
+	file delete $src
+    }
+    return $compiler_available_saved
+}
+
 # Returns 1 if plugin is enabled in gcc.  Returns 0 otherwise.
 proc check_gcc_plugin_enabled { } {
     global CC
@@ -1327,7 +1380,7 @@ proc check_ifunc_available { } {
     global CC
 
     if {![info exists ifunc_available_saved]} {
-        if { [which $CC] == 0 } {
+        if { ![check_compiler_available] } {
 	    set ifunc_available_saved 0
 	    return 0
 	}
@@ -1376,7 +1429,7 @@ proc check_ifunc_attribute_available { } {
     global CC
 
     if {![info exists ifunc_attribute_available_saved]} {
-        if { [which $CC] == 0 } {
+        if { ![check_compiler_available] } {
 	    set ifunc_attribute_available_saved 0
 	    return 0
 	}
@@ -1423,7 +1476,7 @@ proc check_libdl_available { } {
     global CC
 
     if {![info exists libdl_available_saved]} {
-        if { [which $CC] == 0 } {
+        if { ![check_compiler_available] } {
 	    set libdl_available_saved 0
 	    return 0
 	}
@@ -1459,7 +1512,7 @@ proc check_gnu2_tls_available { } {
     global GNU2_CFLAGS
 
     if {![info exists gnu2_tls_available_saved]} {
-        if { [which $CC] == 0 || "$GNU2_CFLAGS" == "" } {
+        if { ![check_compiler_available] || "$GNU2_CFLAGS" == "" } {
 	    set gnu2_tls_available_saved 0
 	    return 0
 	}