testsuite, gdb.btrace: fix 32-bit PIE false positives

For 32-bit position independent executables, GCC generates an extra call to

    __x86.get_pc_thunk.<reg>

which appears in the function call history.  It is correct to appear there
but this confuses the tests, which check for an expected sequence of
functions.

Build with nopie to avoid this complication.

gdb/testsuite/ChangeLog:
2020-12-04  Markus Metzger  <markus.t.metzger@intel.com>

	* gdb.btrace/exception.exp: Build with nopie.
	* gdb.btrace/function_call_history.exp: Likewise.
	* gdb.btrace/unknown_functions.exp: Likewise.

3 files changed, 13 insertions, 5 deletions

diff --git a/gdb/testsuite/gdb.btrace/exception.exp b/gdb/testsuite/gdb.btrace/exception.exp
index 0d24222..dc1a68c 100755
--- a/gdb/testsuite/gdb.btrace/exception.exp
+++ b/gdb/testsuite/gdb.btrace/exception.exp
@@ -22,8 +22,11 @@ if { [skip_btrace_tests] } {
     return -1
 }
 
+# We expect a specific function call history.  This gets messed up with
+# PIE on 32-bit.
 standard_testfile exception.cc
-if [prepare_for_testing "failed to prepare" $testfile $srcfile {c++ debug}] {
+if [prepare_for_testing "failed to prepare" $testfile $srcfile \
+	{nopie c++ debug}] {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.btrace/function_call_history.exp b/gdb/testsuite/gdb.btrace/function_call_history.exp
index 51536ff..871d37b 100644
--- a/gdb/testsuite/gdb.btrace/function_call_history.exp
+++ b/gdb/testsuite/gdb.btrace/function_call_history.exp
@@ -22,8 +22,10 @@ if { [skip_btrace_tests] } {
     return -1
 }
 
+# We expect a specific function call history.  This gets messed up with
+# PIE on 32-bit.
 standard_testfile
-if [prepare_for_testing "failed to prepare" $testfile {} {debug}] {
+if [prepare_for_testing "failed to prepare" $testfile {} {nopie debug}] {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.btrace/unknown_functions.exp b/gdb/testsuite/gdb.btrace/unknown_functions.exp
index 4db9c70..beb1aca 100644
--- a/gdb/testsuite/gdb.btrace/unknown_functions.exp
+++ b/gdb/testsuite/gdb.btrace/unknown_functions.exp
@@ -24,9 +24,12 @@ if { [skip_btrace_tests] } {
 
 standard_testfile
 
-# discard local symbols
-set ldflags "additional_flags=-Wl,-x"
-if [prepare_for_testing "failed to prepare" $testfile $srcfile $ldflags] {
+# We expect a specific function call history.  This gets messed up with
+# PIE on 32-bit.
+#
+# Also discard local symbols.
+if [prepare_for_testing "failed to prepare" $testfile $srcfile \
+	{additional_flags=-Wl,-x nopie}] {
     return -1
 }