[PATCH v2] rs6000: Fix ASAN linker errors for Power ELF V1 ABI [PR113284]

[PATCH v2] rs6000: Fix ASAN linker errors for Power ELF V1 ABI [PR113284]

[Ilya Leoshkevich]

v1: https://inbox.sourceware.org/gcc-patches/20240109105253.332676-1-iii@linux.ibm.com/
v1 -> v2: Move the .LASANPC label to the .text section (Jakub).
          Jakub okay-ed this version in the GCC Bugzilla.

Bootstrap and regtest running on ppc64le-redhat-linux and
powerpc64-linux-gnu.  Ok for trunk when successful?



rs6000_elf_declare_function_name () outputs Power ELF V1 ABI function
entry labels without using ASM_OUTPUT_FUNCTION_LABEL ().  As a result,
.LASANPC labels are not emitted, causing linker errors.

In theory, it is possible to reuse ASM_OUTPUT_FUNCTION_LABEL () by
changing rs6000_output_function_entry () to generate label names
without outputting them, but this would be quite a large change.

Instead, factor out the .LASANPC emitting code from
ASM_OUTPUT_FUNCTION_LABEL () and call it manually.

Fixes: c659dd8bfb55 ("Implement ASM_DECLARE_FUNCTION_NAME using ASM_OUTPUT_FUNCTION_LABEL")
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>

gcc/ChangeLog:

	PR sanitizer/113284
	* config/rs6000/rs6000.cc (rs6000_elf_declare_function_name):
	Use assemble_function_label_final () for Power ELF V1 ABI.
	* output.h (assemble_function_label_final): New function.
	* varasm.cc (assemble_function_label_raw): Use
	assemble_function_label_final ().
	(assemble_function_label_final): New function.
---
 gcc/config/rs6000/rs6000.cc | 1 +
 gcc/output.h                | 4 ++++
 gcc/varasm.cc               | 9 +++++++++
 3 files changed, 14 insertions(+)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 94fbf46f2b6..5d975dab921 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -21357,6 +21357,7 @@ rs6000_elf_declare_function_name (FILE *file, const char *name, tree decl)
       ASM_DECLARE_RESULT (file, DECL_RESULT (decl));
       rs6000_output_function_entry (file, name);
       fputs (":\n", file);
+      assemble_function_label_final ();
       return;
     }
 
diff --git a/gcc/output.h b/gcc/output.h
index c8fe1d2643d..46b0033b221 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -182,6 +182,10 @@ extern const char *get_fnname_from_decl (tree);
    code or data is output after the label.  */
 extern void assemble_function_label_raw (FILE *, const char *);
 
+/* Finish outputting function label.  Needs to be called when outputting
+   function label without using assemble_function_label_raw ().  */
+extern void assemble_function_label_final (void);
+
 /* Output assembler code for the constant pool of a function and associated
    with defining the name of the function.  DECL describes the function.
    NAME is the function's name.  For the constant pool, we use the current
diff --git a/gcc/varasm.cc b/gcc/varasm.cc
index 1a869ae458a..2b633822434 100644
--- a/gcc/varasm.cc
+++ b/gcc/varasm.cc
@@ -1843,6 +1843,15 @@ void
 assemble_function_label_raw (FILE *file, const char *name)
 {
   ASM_OUTPUT_LABEL (file, name);
+  assemble_function_label_final ();
+}
+
+/* Finish outputting function label.  Needs to be called when outputting
+   function label without using assemble_function_label_raw ().  */
+
+void
+assemble_function_label_final (void)
+{
   if ((flag_sanitize & SANITIZE_ADDRESS)
       /* Notify ASAN only about the first function label.  */
       && (in_cold_section_p == first_function_block_is_cold)
-- 
2.43.0