[PATCH][GCC11] IBM Z: fix `section type conflict` with -mindirect-branch-table

[Ilya Leoshkevich via Gcc-patches]

Bootstrapped and regtested on s390x-redhat-linux.  Ok for
releases/gcc-11?



s390_code_end () puts indirect branch tables into separate sections and
tries to switch back to wherever it was in the beginning by calling
switch_to_section (current_function_section ()).

First of all, this is unnecessary - the other backends don't do it.

Furthermore, at this time there is no current function, but if the
last processed function was cold, in_cold_section_p remains set.  This
causes targetm.asm_out.function_section () to call
targetm.section_type_flags (), which in absence of current function
decl classifies the section as SECTION_WRITE.  This causes a section
type conflict with the existing SECTION_CODE.

gcc/ChangeLog:

        * config/s390/s390.c (s390_code_end): Do not switch back to
        code section.

gcc/testsuite/ChangeLog:

        * gcc.target/s390/nobp-section-type-conflict.c: New test.

(cherry picked from commit 8753b13a31c777cdab0265dae0b68534247908f7)
---
 gcc/config/s390/s390.c                        |  1 -
 .../s390/nobp-section-type-conflict.c         | 22 +++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/s390/nobp-section-type-conflict.c

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 8895dd7cc76..2d2e6522eb4 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -16700,7 +16700,6 @@ s390_code_end (void)
              assemble_name_raw (asm_out_file, label_start);
              fputs ("-.\n", asm_out_file);
            }
-         switch_to_section (current_function_section ());
        }
     }
 }
diff --git a/gcc/testsuite/gcc.target/s390/nobp-section-type-conflict.c 
b/gcc/testsuite/gcc.target/s390/nobp-section-type-conflict.c
new file mode 100644
index 00000000000..5d78bc99bb5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/nobp-section-type-conflict.c
@@ -0,0 +1,22 @@
+/* Checks that we don't get error: section type conflict with ‘put_page’.  */
+
+/* { dg-do compile } */
+/* { dg-options "-mindirect-branch=thunk-extern -mfunction-return=thunk-extern 
-mindirect-branch-table -O2" } */
+
+int a;
+int b (void);
+void c (int);
+
+static void
+put_page (void)
+{
+  if (b ())
+    c (a);
+}
+
+__attribute__ ((__section__ (".init.text"), __cold__)) void
+d (void)
+{
+  put_page ();
+  put_page ();
+}
-- 
2.34.1