[v2] LoongArch: Define the macro ASM_PREFERRED_EH_DATA_FORMAT by checking the assembler's support for eh_frame encoding.

Message ID 20220729040220.436005-1-chenglulu@loongson.cn
State New, archived
Headers
Series [v2] LoongArch: Define the macro ASM_PREFERRED_EH_DATA_FORMAT by checking the assembler's support for eh_frame encoding. |

Commit Message

chenglulu July 29, 2022, 4:02 a.m. UTC
  The ASM_PREFERRED_EH_DATA_FORMAT macro before and after modification is as follows:

 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
-  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_absptr)
+  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)

Use the following tests to describe the effect of modifying this macro on the generated
assembly code:

	#include <iostream>
	#include <exception>

	using namespace std;
	int main()
	{

	  try {
		  throw 1;
	  }
	  catch (int i)
	  {
	    cout << i << endl;
	  }
	}

The main comparisons related to the eh_frame section are as follows:

                   OLD                                                                NEW
.LFB1997 = .                                                  |  .LFB1780 = .                                                                                                                              
          .cfi_startproc                                      |          .cfi_startproc
          .cfi_personality 0x80,DW.ref.__gxx_personality_v0   |          .cfi_personality 0x9b,DW.ref.__gxx_personality_v0                                                                                 
          .cfi_lsda 0,.LLSDA1997                              |          .cfi_lsda 0x1b,.LLSDA1780                                

If the assembly file generated by the new gcc is compiled with the binutils of version 2.38, the
following error will be reported:
test.s:74: Error: invalid or unsupported encoding in .cfi_personality
test.s:75: Error: invalid or unsupported encoding in .cfi_lsda

So I think I should judge whether binutils supports this encoding when gcc is configured, and then choose how to define
macro ASM_PREFERRED_EH_DATA_FORMAT.




------------
.eh_frame DW_EH_PE_pcrel encoding format is not supported by gas <= 2.39.
Check if the assembler support DW_EH_PE_PCREL encoding and define .eh_frame
encoding type.

gcc/ChangeLog:

	* config.in: Regenerate.
	* config/loongarch/loongarch.h (ASM_PREFERRED_EH_DATA_FORMAT):
	Select the value of the macro definition according to whether
	HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT is defined.
	* configure: Regenerate.
	* configure.ac: Reinstate HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT test.
---
 gcc/config.in                    |  8 +++++++-
 gcc/config/loongarch/loongarch.h |  5 +++++
 gcc/configure                    | 34 ++++++++++++++++++++++++++++++++
 gcc/configure.ac                 |  8 ++++++++
 4 files changed, 54 insertions(+), 1 deletion(-)
  

Comments

chenglulu July 29, 2022, 7:02 a.m. UTC | #1
在 2022/7/29 下午12:02, Lulu Cheng 写道:
> The ASM_PREFERRED_EH_DATA_FORMAT macro before and after modification is as follows:
>
>   #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
> -  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_absptr)
> +  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
>
> Use the following tests to describe the effect of modifying this macro on the generated
> assembly code:
>
> 	#include <iostream>
> 	#include <exception>
>
> 	using namespace std;
> 	int main()
> 	{
>
> 	  try {
> 		  throw 1;
> 	  }
> 	  catch (int i)
> 	  {
> 	    cout << i << endl;
> 	  }
> 	}
>
> The main comparisons related to the eh_frame section are as follows:
>
>                    OLD                                                                NEW
> .LFB1997 = .                                                  |  .LFB1780 = .
>            .cfi_startproc                                      |          .cfi_startproc
>            .cfi_personality 0x80,DW.ref.__gxx_personality_v0   |          .cfi_personality 0x9b,DW.ref.__gxx_personality_v0
>            .cfi_lsda 0,.LLSDA1997                              |          .cfi_lsda 0x1b,.LLSDA1780
>
> If the assembly file generated by the new gcc is compiled with the binutils of version 2.38, the
> following error will be reported:
> test.s:74: Error: invalid or unsupported encoding in .cfi_personality
> test.s:75: Error: invalid or unsupported encoding in .cfi_lsda
>
> So I think I should judge whether binutils supports this encoding when gcc is configured, and then choose how to define
> macro ASM_PREFERRED_EH_DATA_FORMAT.
>
>
>
>
> ------------
> .eh_frame DW_EH_PE_pcrel encoding format is not supported by gas <= 2.39.
> Check if the assembler support DW_EH_PE_PCREL encoding and define .eh_frame
> encoding type.
>
> gcc/ChangeLog:
>
> 	* config.in: Regenerate.
> 	* config/loongarch/loongarch.h (ASM_PREFERRED_EH_DATA_FORMAT):
> 	Select the value of the macro definition according to whether
> 	HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT is defined.
> 	* configure: Regenerate.
> 	* configure.ac: Reinstate HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT test.
> ---
>   gcc/config.in                    |  8 +++++++-
>   gcc/config/loongarch/loongarch.h |  5 +++++
>   gcc/configure                    | 34 ++++++++++++++++++++++++++++++++
>   gcc/configure.ac                 |  8 ++++++++
>   4 files changed, 54 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config.in b/gcc/config.in
> index 16bb963b45b..413b2bd36cb 100644
> --- a/gcc/config.in
> +++ b/gcc/config.in
> @@ -404,13 +404,19 @@
>   #endif
>   
>   
> +/* Define if your assembler supports eh_frame pcrel encoding. */
> +#ifndef USED_FOR_TARGET
> +#undef HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT
> +#endif
> +
> +
>   /* Define if your assembler supports the R_PPC64_ENTRY relocation. */
>   #ifndef USED_FOR_TARGET
>   #undef HAVE_AS_ENTRY_MARKERS
>   #endif
>   
>   
> -/* Define if your assembler supports explicit relocations. */
> +/* Define if your assembler supports explicit relocation. */
>   #ifndef USED_FOR_TARGET
>   #undef HAVE_AS_EXPLICIT_RELOCS
>   #endif
> diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
> index 89a5bd728fe..8b1288961e4 100644
> --- a/gcc/config/loongarch/loongarch.h
> +++ b/gcc/config/loongarch/loongarch.h
> @@ -1127,8 +1127,13 @@ struct GTY (()) machine_function
>   };
>   #endif
>   
> +#ifdef HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT
> +#define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
> +  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
> +#else
>   #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
>     (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_absptr)
> +#endif
>   
>   /* Do emit .note.GNU-stack by default.  */
>   #ifndef NEED_INDICATE_EXEC_STACK
> diff --git a/gcc/configure b/gcc/configure
> index 7eb9479ae8e..05efa5b01ef 100755
> --- a/gcc/configure
> +++ b/gcc/configure
> @@ -28836,6 +28836,40 @@ if test $gcc_cv_as_loongarch_explicit_relocs = yes; then
>   
>   $as_echo "#define HAVE_AS_EXPLICIT_RELOCS 1" >>confdefs.h
>   
> +fi
> +
> +    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for eh_frame pcrel encoding support" >&5
> +$as_echo_n "checking assembler for eh_frame pcrel encoding support... " >&6; }
> +if ${gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support+:} false; then :
> +  $as_echo_n "(cached) " >&6
> +else
> +  gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support=no
> +  if test x$gcc_cv_as != x; then
> +    $as_echo '.cfi_startproc
> +       .cfi_personality 0x9b,a
> +       .cfi_lsda 0x1b,b
> +       .cfi_endproc' > conftest.s
> +    if { ac_try='$gcc_cv_as $gcc_cv_as_flags  -o conftest.o conftest.s >&5'
> +  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> +  (eval $ac_try) 2>&5
> +  ac_status=$?
> +  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> +  test $ac_status = 0; }; }
> +    then
> +	gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support=yes
> +    else
> +      echo "configure: failed program was" >&5
> +      cat conftest.s >&5
> +    fi
> +    rm -f conftest.o conftest.s
> +  fi
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support" >&5
> +$as_echo "$gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support" >&6; }
> +if test $gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support = yes; then
> +
> +$as_echo "#define HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT 1" >>confdefs.h
> +
>   fi
>   
>       ;;
> diff --git a/gcc/configure.ac b/gcc/configure.ac
> index e5f708c6b38..f70b6c24fda 100644
> --- a/gcc/configure.ac
> +++ b/gcc/configure.ac
> @@ -5302,6 +5302,14 @@ x:
>         [a:pcalau12i $t0,%pc_hi20(a)],,
>         [AC_DEFINE(HAVE_AS_EXPLICIT_RELOCS, 1,
>   	  [Define if your assembler supports explicit relocation.])])
> +    gcc_GAS_CHECK_FEATURE([eh_frame pcrel encoding support],
> +      gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support,,
> +      [.cfi_startproc
> +       .cfi_personality 0x9b,a
> +       .cfi_lsda 0x1b,b
> +       .cfi_endproc],,
> +      [AC_DEFINE(HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT, 1,
> +	  [Define if your assembler supports eh_frame pcrel encoding.])])
>       ;;
>       s390*-*-*)
>       gcc_GAS_CHECK_FEATURE([.gnu_attribute support],


Pushed r13-1885.
  

Patch

diff --git a/gcc/config.in b/gcc/config.in
index 16bb963b45b..413b2bd36cb 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -404,13 +404,19 @@ 
 #endif
 
 
+/* Define if your assembler supports eh_frame pcrel encoding. */
+#ifndef USED_FOR_TARGET
+#undef HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT
+#endif
+
+
 /* Define if your assembler supports the R_PPC64_ENTRY relocation. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_AS_ENTRY_MARKERS
 #endif
 
 
-/* Define if your assembler supports explicit relocations. */
+/* Define if your assembler supports explicit relocation. */
 #ifndef USED_FOR_TARGET
 #undef HAVE_AS_EXPLICIT_RELOCS
 #endif
diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
index 89a5bd728fe..8b1288961e4 100644
--- a/gcc/config/loongarch/loongarch.h
+++ b/gcc/config/loongarch/loongarch.h
@@ -1127,8 +1127,13 @@  struct GTY (()) machine_function
 };
 #endif
 
+#ifdef HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT
+#define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
+  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
+#else
 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
   (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_absptr)
+#endif
 
 /* Do emit .note.GNU-stack by default.  */
 #ifndef NEED_INDICATE_EXEC_STACK
diff --git a/gcc/configure b/gcc/configure
index 7eb9479ae8e..05efa5b01ef 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -28836,6 +28836,40 @@  if test $gcc_cv_as_loongarch_explicit_relocs = yes; then
 
 $as_echo "#define HAVE_AS_EXPLICIT_RELOCS 1" >>confdefs.h
 
+fi
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking assembler for eh_frame pcrel encoding support" >&5
+$as_echo_n "checking assembler for eh_frame pcrel encoding support... " >&6; }
+if ${gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support=no
+  if test x$gcc_cv_as != x; then
+    $as_echo '.cfi_startproc
+       .cfi_personality 0x9b,a
+       .cfi_lsda 0x1b,b
+       .cfi_endproc' > conftest.s
+    if { ac_try='$gcc_cv_as $gcc_cv_as_flags  -o conftest.o conftest.s >&5'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }
+    then
+	gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support=yes
+    else
+      echo "configure: failed program was" >&5
+      cat conftest.s >&5
+    fi
+    rm -f conftest.o conftest.s
+  fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support" >&5
+$as_echo "$gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support" >&6; }
+if test $gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support = yes; then
+
+$as_echo "#define HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT 1" >>confdefs.h
+
 fi
 
     ;;
diff --git a/gcc/configure.ac b/gcc/configure.ac
index e5f708c6b38..f70b6c24fda 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5302,6 +5302,14 @@  x:
       [a:pcalau12i $t0,%pc_hi20(a)],,
       [AC_DEFINE(HAVE_AS_EXPLICIT_RELOCS, 1,
 	  [Define if your assembler supports explicit relocation.])])
+    gcc_GAS_CHECK_FEATURE([eh_frame pcrel encoding support],
+      gcc_cv_as_loongarch_eh_frame_pcrel_encoding_support,,
+      [.cfi_startproc
+       .cfi_personality 0x9b,a
+       .cfi_lsda 0x1b,b
+       .cfi_endproc],,
+      [AC_DEFINE(HAVE_AS_EH_FRAME_PCREL_ENCODING_SUPPORT, 1,
+	  [Define if your assembler supports eh_frame pcrel encoding.])])
     ;;
     s390*-*-*)
     gcc_GAS_CHECK_FEATURE([.gnu_attribute support],