[2/8] gen-pert-test: compiler-info

diff --git a/gdb/testsuite/gdb.base/watchpoint.exp  
b/gdb/testsuite/gdb.base/watchpoint.exp
index b2924d7..fcc9a8d 100644
--- a/gdb/testsuite/gdb.base/watchpoint.exp
+++ b/gdb/testsuite/gdb.base/watchpoint.exp
@@ -464,12 +464,11 @@  proc test_complex_watchpoint {} {
  		pass $test
  	    }
  	    -re "can't compute CFA for this frame.*\r\n$gdb_prompt $" {
-		global compiler_info no_hw
+		global no_hw

  		# GCC < 4.5.0 does not get LOCATIONS_VALID set by dwarf2read.c.
  		# Therefore epilogue unwinder gets applied which is
  		# incompatible with dwarf2_frame_cfa.
-		verbose -log "compiler_info: $compiler_info"
  		if {$no_hw && ([test_compiler_info {gcc-[0-3]-*}]
  			       || [test_compiler_info {gcc-4-[0-4]-*}])} {
  		    xfail "$test (old GCC has broken watchpoints in epilogues)"
diff --git a/gdb/testsuite/gdb.cp/temargs.exp  
b/gdb/testsuite/gdb.cp/temargs.exp
index e5aff51..f086a63 100644
--- a/gdb/testsuite/gdb.cp/temargs.exp
+++ b/gdb/testsuite/gdb.cp/temargs.exp
@@ -34,7 +34,6 @@  if {![runto_main]} {
  # NOTE: prepare_for_testing calls get_compiler_info, which we need
  # for the test_compiler_info calls.
  # gcc 4.4 and earlier don't emit enough info for some of our template  
tests.
-verbose -log "compiler_info: $compiler_info"
  set have_older_template_gcc 0
  set have_pr_41736_fixed 1
  set have_pr_45024_fixed 1
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 0805de9..4edc95f 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -2788,12 +2788,20 @@  gdb_caching_proc target_is_gdbserver {
      return $is_gdbserver
  }

-set compiler_info		"unknown"
+# N.B. compiler_info is intended to be local to this file.
+# Call test_compiler_info with no arguments to fetch its value.
+# Yes, this is counterintuitive when there's get_compiler_info,
+# but that's the current API.
+if [info exists compiler_info] {
+    unset compiler_info
+}
+
  set gcc_compiled		0
  set hp_cc_compiler		0
  set hp_aCC_compiler		0

  # Figure out what compiler I am using.
+# The result is cached so only the first invocation runs the compiler.
  #
  # ARG can be empty or "C++".  If empty, "C" is assumed.
  #
@@ -2860,6 +2868,11 @@  proc get_compiler_info {{arg ""}} {
      global hp_cc_compiler
      global hp_aCC_compiler

+    if [info exists compiler_info] {
+	# Already computed.
+	return 0
+    }
+
      # Choose which file to preprocess.
      set ifile "${srcdir}/lib/compiler.c"
      if { $arg == "c++" } {
@@ -2901,8 +2914,14 @@  proc get_compiler_info {{arg ""}} {
  	}
      }

-    # Reset to unknown compiler if any diagnostics happened.
+    # Set to unknown if for some reason compiler_info didn't get defined.
+    if ![info exists compiler_info] {
+	verbose -log "get_compiler_info: compiler_info not provided"
+	set compiler_info "unknown"
+    }
+    # Also set to unknown compiler if any diagnostics happened.
      if { $unknown } {
+	verbose -log "get_compiler_info: got unexpected diagnostics"
  	set compiler_info "unknown"
      }

@@ -2936,18 +2955,18 @@  proc get_compiler_info {{arg ""}} {
      return 0
  }

+# Return the compiler_info string if no arg is provided.
+# Otherwise the argument is a glob-style expression to match against
+# compiler_info.
+
  proc test_compiler_info { {compiler ""} } {
      global compiler_info
+    get_compiler_info

-     # if no arg, return the compiler_info string
-
-     if [string match "" $compiler] {
-         if [info exists compiler_info] {
-             return $compiler_info
-         } else {
-             perror "No compiler info found."
-         }
-     }
+    # If no arg, return the compiler_info string.
+    if [string match "" $compiler] {
+	return $compiler_info
+    }

      return [string match $compiler $compiler_info]
  }