From 44365e88c0e021a7f734e44aa845f1e96cd83389 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Mon, 18 Jan 2021 09:38:22 +1030
Subject: [PATCH] PR27198, segv in S_IS_WEAK

Fix a NULL dereference seen when assembling invalid input.

	PR 27198
	* config/tc-i386.c (need_plt32_p): Return FALSE for NULL symbol.
	* testsuite/gas/i386/pr27198.d,
	* gas/testsuite/gas/i386/pr27198.err,
	* gas/testsuite/gas/i386/pr27198.s: New test.
	* gas/testsuite/gas/i386/i386.exp: Run it.
---
 gas/ChangeLog                      | 9 +++++++++
 gas/config/tc-i386.c               | 3 +++
 gas/testsuite/gas/i386/i386.exp    | 1 +
 gas/testsuite/gas/i386/pr27198.d   | 2 ++
 gas/testsuite/gas/i386/pr27198.err | 5 +++++
 gas/testsuite/gas/i386/pr27198.s   | 1 +
 6 files changed, 21 insertions(+)
 create mode 100644 gas/testsuite/gas/i386/pr27198.d
 create mode 100644 gas/testsuite/gas/i386/pr27198.err
 create mode 100644 gas/testsuite/gas/i386/pr27198.s

diff --git a/gas/ChangeLog b/gas/ChangeLog
index ab5cc98ba64..3d242869eac 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2021-01-18  Alan Modra  <amodra@gmail.com>
+
+	PR 27198
+	* config/tc-i386.c (need_plt32_p): Return FALSE for NULL symbol.
+	* testsuite/gas/i386/pr27198.d,
+	* gas/testsuite/gas/i386/pr27198.err,
+	* gas/testsuite/gas/i386/pr27198.s: New test.
+	* gas/testsuite/gas/i386/i386.exp: Run it.
+
 2021-01-15  Nelson Chu  <nelson.chu@sifive.com>
 
 	* config/tc-riscv.c: Indent and GNU coding standards tidy,
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index a7d2ff1c1f9..b0140e1128a 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -8628,6 +8628,9 @@ need_plt32_p (symbolS *s)
   if (!object_64bit)
     return FALSE;
 
+  if (s == NULL)
+    return FALSE;
+
   /* Weak or undefined symbol need PLT32 relocation.  */
   if (S_IS_WEAK (s) || !S_IS_DEFINED (s))
     return TRUE;
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index c9bca8ab215..b4a75e4552f 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -1293,6 +1293,7 @@ if [gas_64_check] then {
 	}
 
     }
+    run_dump_test pr27198
 
     set ASFLAGS "$old_ASFLAGS --64"
 
diff --git a/gas/testsuite/gas/i386/pr27198.d b/gas/testsuite/gas/i386/pr27198.d
new file mode 100644
index 00000000000..6cf0d547dcd
--- /dev/null
+++ b/gas/testsuite/gas/i386/pr27198.d
@@ -0,0 +1,2 @@
+#as:
+#error_output: pr27198.err
diff --git a/gas/testsuite/gas/i386/pr27198.err b/gas/testsuite/gas/i386/pr27198.err
new file mode 100644
index 00000000000..1f71543e1d4
--- /dev/null
+++ b/gas/testsuite/gas/i386/pr27198.err
@@ -0,0 +1,5 @@
+#failif
+
+#...
+.*Internal error.*
+#pass
diff --git a/gas/testsuite/gas/i386/pr27198.s b/gas/testsuite/gas/i386/pr27198.s
new file mode 100644
index 00000000000..9ac98982f48
--- /dev/null
+++ b/gas/testsuite/gas/i386/pr27198.s
@@ -0,0 +1 @@
+ call (%rax)junk
-- 
2.30.2