[Ada] Infinite loop on illegal declaration

This patch updates predicate Null_Status to prevent an infinite
recursion when the argument is an illegal object declaration of an
access type.

2019-07-11  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* sem_util.adb (Null_Status): Assume that an erroneous construct
	has an undefined null status.

gcc/testsuite/

	* gnat.dg/self_ref1.adb: New testcase.

From-SVN: r273389

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index a17ab7e25fd205969a7ffa1dcaf048783165a890..0a1bd24554508267b4ade2b9d49533de4ad4ed63 100644 (file)
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,8 @@
+2019-07-11  Hristian Kirtchev  <kirtchev@adacore.com>
+
+       * sem_util.adb (Null_Status): Assume that an erroneous construct
+       has an undefined null status.
+
 2019-07-11  Hristian Kirtchev  <kirtchev@adacore.com>
 
        * checks.adb, exp_ch6.adb, gnat1drv.adb, sem_aux.adb,

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index 147c281c79756c2078f8356d77be4350b28e7dc4..04d981a6a86a2220cc49cba73f82b1904da239d3 100644 (file)
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -22367,9 +22367,15 @@ package body Sem_Util is
    --  Start of processing for Null_Status
 
    begin
+      --  Prevent cascaded errors or infinite loops when trying to determine
+      --  the null status of an erroneous construct.
+
+      if Error_Posted (N) then
+         return Unknown;
+
       --  An allocator always creates a non-null value
 
-      if Nkind (N) = N_Allocator then
+      elsif Nkind (N) = N_Allocator then
          return Is_Non_Null;
 
       --  Taking the 'Access of something yields a non-null value

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bbfada284f969f6698de6f8c6b71a5d09aad5732..f0d066db984002cb0f222f0f701b59cbbd9369e3 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-07-11  Hristian Kirtchev  <kirtchev@adacore.com>
+
+       * gnat.dg/self_ref1.adb: New testcase.
+
 2019-07-11  Ed Schonberg  <schonberg@adacore.com>
 
        * gnat.dg/predicate11.adb: New testcase.

diff --git a/gcc/testsuite/gnat.dg/self_ref1.adb b/gcc/testsuite/gnat.dg/self_ref1.adb
new file mode 100644 (file)
index 0000000..a65dbd9
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/self_ref1.adb
@@ -0,0 +1,11 @@
+--  { dg-do compile }
+
+procedure Self_Ref1 is
+   type Integer_Ptr is access all Integer;
+   Ptr : constant Integer_Ptr := Integer_Ptr (Ptr); --  { dg-error "object \"Ptr\" cannot be used before end of its declaration" }
+
+begin
+   if Ptr /= null then
+      null;
+   end if;
+end Self_Ref1;