[gdb/testsuite] Use allocator_may_return_null=1 in two test-cases

Simon reported [1] that recent commit 06e967dbc9b ("[gdb/python] Throw
MemoryError in inferior.read_memory if malloc fails") introduced
AddressSanitizer allocation-size-too-big errors in the two test-cases
affected by this commit.

Fix this by suppressing the error in the two test-cases using
allocator_may_return_null=1.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

[1] https://sourceware.org/pipermail/gdb-patches/2024-April/208171.html

3 files changed, 33 insertions, 6 deletions

diff --git a/gdb/testsuite/gdb.dap/memory.exp b/gdb/testsuite/gdb.dap/memory.exp
index 4e2e361..7082706 100644
--- a/gdb/testsuite/gdb.dap/memory.exp
+++ b/gdb/testsuite/gdb.dap/memory.exp
@@ -25,8 +25,15 @@ if {[build_executable ${testfile}.exp $testfile] == -1} {
     return
 }
 
-if {[dap_initialize] == ""} {
-    return
+save_vars { env(ASAN_OPTIONS) } {
+    # The request readMemory with count 18446744073709551615 triggers address
+    # sanitizer.  Suppress the error, leaving us with just this warning:
+    #   WARNING: AddressSanitizer failed to allocate 0xffffffffffffffff bytes
+    set_sanitizer ASAN_OPTIONS allocator_may_return_null 1
+
+    if {[dap_initialize] == ""} {
+	return
+    }
 }
 
 set line [gdb_get_line_number "BREAK"]
diff --git a/gdb/testsuite/gdb.python/py-inferior.exp b/gdb/testsuite/gdb.python/py-inferior.exp
index 4c19e25..e74fbfd 100644
--- a/gdb/testsuite/gdb.python/py-inferior.exp
+++ b/gdb/testsuite/gdb.python/py-inferior.exp
@@ -27,7 +27,15 @@ if { [gdb_compile_pthreads ${srcdir}/${subdir}/${srcfile} ${binfile} executable
 }
 
 # Start with a fresh gdb.
-clean_restart ${testfile}
+save_vars { env(ASAN_OPTIONS) } {
+    # The call to gdb.selected_inferior().read_memory (0, 0xffffffffffffffff)
+    # triggers address sanitizer.  Suppress the error, leaving us with just
+    # this warning:
+    #   WARNING: AddressSanitizer failed to allocate 0xffffffffffffffff bytes
+    set_sanitizer ASAN_OPTIONS allocator_may_return_null 1
+
+    clean_restart ${testfile}
+}
 
 switch [get_endianness] {
     little { set python_pack_char "<" }
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index d48ea37..ddee928 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -45,9 +45,9 @@ proc cond_wrap { cond wrap body } {
     }
 }
 
-# Add VAR_ID=VAL to ENV_VAR, unless ENV_VAR already contains a VAR_ID setting.
+# Helper function for set_sanitizer/set_sanitizer_default.
 
-proc set_sanitizer_default { env_var var_id val } {
+proc set_sanitizer_1 { env_var var_id val default} {
     global env
 
     if { ![info exists env($env_var) ]
@@ -57,7 +57,7 @@ proc set_sanitizer_default { env_var var_id val } {
 	return
     }
 
-    if { [regexp $var_id= $env($env_var)] } {
+    if { $default && [regexp $var_id= $env($env_var)] } {
 	# Don't set var_id.  It's already set by the user, leave as is.
 	# Note that we could probably get the same result by unconditionally
 	# prepending it, but this way is less likely to cause confusion.
@@ -68,6 +68,18 @@ proc set_sanitizer_default { env_var var_id val } {
     append env($env_var) : $var_id=$val
 }
 
+# Add VAR_ID=VAL to ENV_VAR.
+
+proc set_sanitizer { env_var var_id val } {
+    set_sanitizer_1 $env_var $var_id $val 0
+}
+
+# Add VAR_ID=VAL to ENV_VAR, unless ENV_VAR already contains a VAR_ID setting.
+
+proc set_sanitizer_default { env_var var_id val } {
+    set_sanitizer_1 $env_var $var_id $val 1
+}
+
 set_sanitizer_default TSAN_OPTIONS suppressions \
     $srcdir/../tsan-suppressions.txt