diff mbox

xtensa: Avoid designated inits, for C++ compliance

Message ID 20160826090148.GA27461@host1.jankratochvil.net
State New
Headers show

Commit Message

Jan Kratochvil Aug. 26, 2016, 9:01 a.m. UTC 
On Thu, 25 Aug 2016 13:56:25 +0200, Andreas Arnez wrote:
> C++ does not officially support designators in initializer lists.

I could miss something about the transition to C++ but C++ was not intended to
make the sources worse, it should improve the sources.  The checked in change
makes the source apparently more error prone to future changes.  Why not the
attached?

Besides that is only one step; the ctor should be constexpr I guess, but that
is C++11 again.

I have noticed now the C++ conversion does not seem to be complete to me
- struct gdbarch_tdep is defined differently for different translation units,
this violates:
	https://en.wikipedia.org/wiki/One_Definition_Rule


Jan

Comments

Eli Zaretskii Aug. 26, 2016, 9:07 a.m. UTC | #1 
> Date: Fri, 26 Aug 2016 11:01:48 +0200
> From: Jan Kratochvil <jan.kratochvil@redhat.com>
> Cc: gdb-patches@sourceware.org, Pedro Alves <palves@redhat.com>
> 
> 
> [1:text/plain Hide]
> 
> On Thu, 25 Aug 2016 13:56:25 +0200, Andreas Arnez wrote:
> > C++ does not officially support designators in initializer lists.
> 
> I could miss something about the transition to C++ but C++ was not intended to
> make the sources worse, it should improve the sources.  The checked in change
> makes the source apparently more error prone to future changes.  Why not the
> attached?

Because it's C++, not C?
Pedro Alves Aug. 26, 2016, 9:39 a.m. UTC | #2 
On 08/26/2016 10:01 AM, Jan Kratochvil wrote:
> On Thu, 25 Aug 2016 13:56:25 +0200, Andreas Arnez wrote:
>> C++ does not officially support designators in initializer lists.
> 
> I could miss something about the transition to C++ (...)

You're missing that we haven't dropped support for building with
a C compiler yet...

We're still doing many 7.12 backports, so I was waiting for that
to stabilize before proposing to drop C support.

> The checked in change
> makes the source apparently more error prone to future changes.  Why not the
> attached?

Note that this header is meant to be replaced as part of an "overlay".
See:

 http://wiki.linux-xtensa.org/index.php/Toolchain_Overlay_File
 https://www.sourceware.org/ml/gdb-patches/2015-04/msg00695.html

> I have noticed now the C++ conversion does not seem to be complete to me
> - struct gdbarch_tdep is defined differently for different translation units,
> this violates:
> 	https://en.wikipedia.org/wiki/One_Definition_Rule

Right, we're not LTO-ready yet.  Note -Wodr (w/ -flto) helps find these.

Thanks,
Pedro Alves
Jan Kratochvil Aug. 26, 2016, 10:09 a.m. UTC | #3 
On Fri, 26 Aug 2016 11:39:27 +0200, Pedro Alves wrote:
> We're still doing many 7.12 backports, so I was waiting for that
> to stabilize before proposing to drop C support.

Ah, OK.


> > 	https://en.wikipedia.org/wiki/One_Definition_Rule
> 
> Right, we're not LTO-ready yet.  Note -Wodr (w/ -flto) helps find these.

In this case there would be gdbarch_tdep() ctor handy but that is also not
applicable without ODR.  OK, I see I missed GDB still does not require C++.


Jan
diff mbox

Patch

diff --git a/gdb/xtensa-config.c b/gdb/xtensa-config.c
index 0773eda..99da40f 100644
--- a/gdb/xtensa-config.c
+++ b/gdb/xtensa-config.c
@@ -215,7 +215,54 @@  xtensa_register_t rmap[] =
 
 
 
-#ifdef XTENSA_CONFIG_INSTANTIATE
-XTENSA_CONFIG_INSTANTIATE(rmap,0)
-#endif
-
+class XtensaTdep:public gdbarch_tdep {
+public:
+  XtensaTdep() {
+    target_flags = 0;
+    spill_location = -1;
+    spill_size = 0;
+    unused = 0;
+    call_abi = (XSHAL_ABI == XTHAL_ABI_CALL0
+		? CallAbiCall0Only
+		: CallAbiDefault);
+    debug_interrupt_level = XCHAL_DEBUGLEVEL;
+    icache_line_bytes = XCHAL_ICACHE_LINESIZE;
+    dcache_line_bytes = XCHAL_DCACHE_LINESIZE;
+    dcache_writeback = XCHAL_DCACHE_IS_WRITEBACK;
+    isa_use_windowed_registers = (XSHAL_ABI != XTHAL_ABI_CALL0);
+    isa_use_density_instructions = XCHAL_HAVE_DENSITY;
+    isa_use_exceptions = XCHAL_HAVE_EXCEPTIONS;
+    isa_use_ext_l32r = XSHAL_USE_ABSOLUTE_LITERALS;
+    isa_max_insn_size = XCHAL_MAX_INSTRUCTION_SIZE;
+    debug_num_ibreaks = XCHAL_NUM_IBREAK;
+    debug_num_dbreaks = XCHAL_NUM_DBREAK;
+    regmap = rmap;
+    num_regs = 0;
+    num_nopriv_regs = 0;
+    num_pseudo_regs = 0;
+    num_aregs = XCHAL_NUM_AREGS;
+    num_contexts = XCHAL_NUM_CONTEXTS;
+    ar_base = -1;
+    a0_base = -1;
+    wb_regnum = -1;
+    ws_regnum = -1;
+    pc_regnum = -1;
+    ps_regnum = -1;
+    lbeg_regnum = -1;
+    lend_regnum = -1;
+    lcount_regnum = -1;
+    sar_regnum = -1;
+    litbase_regnum = -1;
+    interrupt_regnum = -1;
+    interrupt2_regnum = -1;
+    cpenable_regnum = -1;
+    debugcause_regnum = -1;
+    exccause_regnum = -1;
+    excvaddr_regnum = -1;
+    max_register_raw_size = 0;
+    max_register_virtual_size = 0;
+    fp_layout = 0;
+    fp_layout_bytes = 0;
+    gregmap = 0;
+  }
+} xtensa_tdep;
diff --git a/gdb/xtensa-tdep.h b/gdb/xtensa-tdep.h
index c83e312..1ddfb73 100644
--- a/gdb/xtensa-tdep.h
+++ b/gdb/xtensa-tdep.h
@@ -222,61 +222,6 @@  struct gdbarch_tdep
   struct ctype_cache *type_entries;
 };
 
-/* Macro to instantiate a gdbarch_tdep structure.  */
-
-#define XTENSA_GDBARCH_TDEP_INSTANTIATE(rmap,spillsz)			\
-  {									\
-    0,				/* target_flags */			\
-    -1,				/* spill_location */			\
-    (spillsz),			/* spill_size */			\
-    0,				/* unused */				\
-    (XSHAL_ABI == XTHAL_ABI_CALL0					\
-     ? CallAbiCall0Only							\
-     : CallAbiDefault),		/* call_abi */				\
-    XCHAL_DEBUGLEVEL,		/* debug_interrupt_level */		\
-    XCHAL_ICACHE_LINESIZE,	/* icache_line_bytes */			\
-    XCHAL_DCACHE_LINESIZE,	/* dcache_line_bytes */			\
-    XCHAL_DCACHE_IS_WRITEBACK,  /* dcache_writeback */			\
-    (XSHAL_ABI != XTHAL_ABI_CALL0),   /* isa_use_windowed_registers */	\
-    XCHAL_HAVE_DENSITY,		 /* isa_use_density_instructions */	\
-    XCHAL_HAVE_EXCEPTIONS,	 /* isa_use_exceptions */		\
-    XSHAL_USE_ABSOLUTE_LITERALS, /* isa_use_ext_l32r */			\
-    XCHAL_MAX_INSTRUCTION_SIZE,  /* isa_max_insn_size */		\
-    XCHAL_NUM_IBREAK,		 /* debug_num_ibreaks */		\
-    XCHAL_NUM_DBREAK,		 /* debug_num_dbreaks */		\
-    rmap,			 /* regmap */				\
-    0,				 /* num_regs */				\
-    0,				 /* num_nopriv_regs */			\
-    0,				 /* num_pseudo_regs */			\
-    XCHAL_NUM_AREGS,		 /* num_aregs */			\
-    XCHAL_NUM_CONTEXTS,		 /* num_contexts */			\
-    -1,				 /* ar_base */				\
-    -1,				 /* a0_base */				\
-    -1,				 /* wb_regnum */			\
-    -1,				 /* ws_regnum */			\
-    -1,				 /* pc_regnum */			\
-    -1,				 /* ps_regnum */			\
-    -1,				 /* lbeg_regnum */			\
-    -1,				 /* lend_regnum */			\
-    -1,				 /* lcount_regnum */			\
-    -1,				 /* sar_regnum */			\
-    -1,				 /* litbase_regnum */			\
-    -1,				 /* interrupt_regnum */			\
-    -1,				 /* interrupt2_regnum */		\
-    -1,				 /* cpenable_regnum */			\
-    -1,				 /* debugcause_regnum */		\
-    -1,				 /* exccause_regnum */			\
-    -1,				 /* excvaddr_regnum */			\
-    0,				 /* max_register_raw_size */		\
-    0,				 /* max_register_virtual_size */	\
-    0,				 /* fp_layout */			\
-    0,				 /* fp_layout_bytes */			\
-    0,				 /* gregmap */				\
-  }
-#define XTENSA_CONFIG_INSTANTIATE(rmap,spill_size)	\
-	struct gdbarch_tdep xtensa_tdep = \
-	  XTENSA_GDBARCH_TDEP_INSTANTIATE(rmap,spill_size);
-
 #ifndef XCHAL_NUM_CONTEXTS
 #define XCHAL_NUM_CONTEXTS	0
 #endif