[PATCH] Fix up GCC_EXEC_PREFIX handling with ALT_*_UNDER_TEST

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

I've noticed that when running
make check ALT_CC_UNDER_TEST=gcc ALT_CXX_UNDER_TEST=g++
when the newly built compiler is built into a different prefix
than the system compiler (4.8.x or 4.4.x) lots of tests fail with
errors where the system compiler either couldn't find headers
or even can't exec cc1*.

{set,restore}_ld_library_path_env_vars already sets/restores
GCC_EXEC_PREFIX env var, but unfortunately compat-use-alt-compiler
doesn't restore_ld_library_path_env_vars, instead it
set_ld_library_path_env_vars with just a different ld_library_path.
This patch doesn't change that, supposedly someone needs that, but
just makes sure GCC_EXEC_PREFIX has the original value (or none if it wasn't
in the environment) when invoking the alt compiler.

Tested on x86_64-linux and i686-linux, ok for trunk/4.9?

2014-05-30  Jakub Jelinek  <jakub@redhat.com>

	* lib/target-libpath.exp (set_gcc_exec_prefix_env_var,
	restore_gcc_exec_prefix_env_var): New procedures.
	(set_ld_library_path_env_vars,
	restore_ld_library_path_env_vars): Use them.
	* lib/c-compat.exp: Load target-libpath.exp.
	(compat-use-alt-compiler): Call restore_gcc_exec_prefix_env_var.
	(compat-use-tst-compiler): Call set_gcc_exec_prefix_env_var.
	* g++.dg/compat/compat.exp (compat-use-alt-compiler): Call
	restore_gcc_exec_prefix_env_var.
	* g++.dg/compat/struct-layout-1.exp (compat-use-alt-compiler):
	Likewise.

--- gcc/testsuite/lib/target-libpath.exp.jj	2014-03-20 16:29:20.000000000 +0100
+++ gcc/testsuite/lib/target-libpath.exp	2014-05-29 19:32:58.192043417 +0200
@@ -28,6 +28,21 @@ set orig_gcc_exec_prefix_checked 0
 
 
 #######################################
+# proc set_gcc_exec_prefix_env_var { }
+#######################################
+
+proc set_gcc_exec_prefix_env_var { } {
+  global TEST_GCC_EXEC_PREFIX
+  global env
+
+  # Set GCC_EXEC_PREFIX for the compiler under test to pick up files not in
+  # the build tree from a specified location (normally the install tree).
+  if [info exists TEST_GCC_EXEC_PREFIX] {
+    setenv GCC_EXEC_PREFIX "$TEST_GCC_EXEC_PREFIX"
+  }
+}
+
+#######################################
 # proc set_ld_library_path_env_vars { }
 #######################################
 
@@ -49,7 +64,6 @@ proc set_ld_library_path_env_vars { } {
   global orig_ld_library_path_64
   global orig_dyld_library_path
   global orig_gcc_exec_prefix
-  global TEST_GCC_EXEC_PREFIX
   global env
 
   # Save the original GCC_EXEC_PREFIX.
@@ -61,11 +75,7 @@ proc set_ld_library_path_env_vars { } {
     set orig_gcc_exec_prefix_checked 1
   }
 
-  # Set GCC_EXEC_PREFIX for the compiler under test to pick up files not in
-  # the build tree from a specified location (normally the install tree).
-  if [info exists TEST_GCC_EXEC_PREFIX] {
-    setenv GCC_EXEC_PREFIX "$TEST_GCC_EXEC_PREFIX"
-  }
+  set_gcc_exec_prefix_env_var
 
   # Setting the ld library path causes trouble when testing cross-compilers.
   if { [is_remote target] } {
@@ -164,6 +174,22 @@ proc set_ld_library_path_env_vars { } {
 }
 
 #######################################
+# proc restore_gcc_exec_prefix_env_var { }
+#######################################
+
+proc restore_gcc_exec_prefix_env_var { } {
+  global orig_gcc_exec_prefix_saved
+  global orig_gcc_exec_prefix
+  global env
+
+  if { $orig_gcc_exec_prefix_saved } {
+    setenv GCC_EXEC_PREFIX "$orig_gcc_exec_prefix"
+  } elseif [info exists env(GCC_EXEC_PREFIX)] {
+    unsetenv GCC_EXEC_PREFIX
+  }
+}
+
+#######################################
 # proc restore_ld_library_path_env_vars { }
 #######################################
 
@@ -175,21 +201,15 @@ proc restore_ld_library_path_env_vars {
   global orig_ld_library_path_32_saved
   global orig_ld_library_path_64_saved
   global orig_dyld_library_path_saved
-  global orig_gcc_exec_prefix_saved
   global orig_ld_library_path
   global orig_ld_run_path
   global orig_shlib_path
   global orig_ld_library_path_32
   global orig_ld_library_path_64
   global orig_dyld_library_path
-  global orig_gcc_exec_prefix
   global env
 
-  if { $orig_gcc_exec_prefix_saved } {
-    setenv GCC_EXEC_PREFIX "$orig_gcc_exec_prefix"
-  } elseif [info exists env(GCC_EXEC_PREFIX)] {
-    unsetenv GCC_EXEC_PREFIX
-  }
+  restore_gcc_exec_prefix_env_var
 
   if { $orig_environment_saved == 0 } {
     return
--- gcc/testsuite/lib/c-compat.exp.jj	2014-01-03 11:40:40.000000000 +0100
+++ gcc/testsuite/lib/c-compat.exp	2014-05-29 19:33:15.870952346 +0200
@@ -28,6 +28,7 @@ global compat_skip_list
 # compilers for compatibility tests.
 
 load_lib target-supports.exp
+load_lib target-libpath.exp
 
 #
 # compat-use-alt-compiler -- make the alternate compiler the default
@@ -47,6 +48,7 @@ proc compat-use-alt-compiler { } {
 	if { $compat_alt_color == 0 } then {
 	    regsub -- "-fdiagnostics-color=never" $TEST_ALWAYS_FLAGS "" TEST_ALWAYS_FLAGS
 	}
+	restore_gcc_exec_prefix_env_var
     }
 }
 
@@ -64,6 +66,7 @@ proc compat-use-tst-compiler { } {
     if { $compat_same_alt == 0 } then {
 	set GCC_UNDER_TEST $compat_save_gcc_under_test
 	set TEST_ALWAYS_FLAGS $compat_save_TEST_ALWAYS_FLAGS
+	set_gcc_exec_prefix_env_var
     }
 }
 
--- gcc/testsuite/g++.dg/compat/compat.exp.jj	2014-01-03 11:40:43.000000000 +0100
+++ gcc/testsuite/g++.dg/compat/compat.exp	2014-05-29 19:28:57.227272946 +0200
@@ -55,6 +55,7 @@ proc compat-use-alt-compiler { } {
 	set ALWAYS_CXXFLAGS ""
 	set ld_library_path $alt_ld_library_path
 	set_ld_library_path_env_vars
+	restore_gcc_exec_prefix_env_var
     }
 }
 
--- gcc/testsuite/g++.dg/compat/struct-layout-1.exp.jj	2014-01-03 11:40:43.000000000 +0100
+++ gcc/testsuite/g++.dg/compat/struct-layout-1.exp	2014-05-29 19:29:58.050962141 +0200
@@ -60,6 +60,7 @@ proc compat-use-alt-compiler { } {
 	set ALWAYS_CXXFLAGS ""
 	set ld_library_path $alt_ld_library_path
 	set_ld_library_path_env_vars
+	restore_gcc_exec_prefix_env_var
     }
 }
 

	Jakub