And use that to speed up the libgcc unwinder.
* gcc/debug.h (dwarf_reg_sizes_constant): Declare.
* gcc/dwarf2cfi.cc (dwarf_reg_sizes_constant): New function.
* gcc/c-family/c-cppbuiltin.c
(__LIBGCC_DWARF_REG_SIZES_CONSTANT__): Define if constant is
known.
libgcc/
* unwind-dw2.c (dwarf_reg_size): New function.
(_Unwind_GetGR, _Unwind_SetGR, _Unwind_SetGRPtr)
(_Unwind_SetSpColumn, uw_install_context_1): Use it.
(uw_init_context_1): Do not initialize dwarf_reg_size_table
if not in use.
---
gcc/c-family/c-cppbuiltin.cc | 6 ++++++
gcc/debug.h | 2 ++
gcc/dwarf2cfi.cc | 23 ++++++++++++++++++++
libgcc/unwind-dw2.c | 41 +++++++++++++++++++++++++-----------
4 files changed, 60 insertions(+), 12 deletions(-)
diff --git a/gcc/c-family/c-cppbuiltin.cc b/gcc/c-family/c-cppbuiltin.cc
index cdb658f6ac9..ab98bf3b059 100644
--- a/gcc/c-family/c-cppbuiltin.cc
+++ b/gcc/c-family/c-cppbuiltin.cc
@@ -1515,6 +1515,12 @@ c_cpp_builtins (cpp_reader *pfile)
#endif
builtin_define_with_int_value ("__LIBGCC_DWARF_FRAME_REGISTERS__",
DWARF_FRAME_REGISTERS);
+ {
+ int value = dwarf_reg_sizes_constant ();
+ if (value > 0)
+ builtin_define_with_int_value ("__LIBGCC_DWARF_REG_SIZES_CONSTANT__",
+ value);
+ }
#ifdef EH_RETURN_STACKADJ_RTX
cpp_define (pfile, "__LIBGCC_EH_RETURN_STACKADJ_RTX__");
#endif
diff --git a/gcc/debug.h b/gcc/debug.h
index fe85115d5f3..6bcc8da1f76 100644
--- a/gcc/debug.h
+++ b/gcc/debug.h
@@ -245,6 +245,8 @@ extern const struct gcc_debug_hooks vmsdbg_debug_hooks;
/* Dwarf2 frame information. */
+extern int dwarf_reg_sizes_constant ();
+
extern void dwarf2out_begin_prologue (unsigned int, unsigned int,
const char *);
extern void dwarf2out_vms_end_prologue (unsigned int, const char *);
diff --git a/gcc/dwarf2cfi.cc b/gcc/dwarf2cfi.cc
index b29173b2156..d45d20478b4 100644
--- a/gcc/dwarf2cfi.cc
+++ b/gcc/dwarf2cfi.cc
@@ -334,6 +334,29 @@ generate_dwarf_reg_sizes (poly_uint16 *sizes)
targetm.init_dwarf_reg_sizes_extra (sizes);
}
+/* Return 0 if the DWARF register sizes are not constant, otherwise
+ return the size constant. */
+
+int
+dwarf_reg_sizes_constant ()
+{
+ poly_uint16 *sizes = XALLOCAVEC (poly_uint16, DWARF_FRAME_REGISTERS);
+ generate_dwarf_reg_sizes (sizes);
+
+ int result;
+ for (unsigned int i = 0; i < DWARF_FRAME_REGISTERS; i++)
+ {
+ unsigned short value;
+ if (!sizes[i].is_constant (&value))
+ return 0;
+ if (i == 0)
+ result = value;
+ else if (result != value)
+ return 0;
+ }
+ return result;
+}
+
/* Generate code to initialize the dwarf register size table located
at the provided ADDRESS. */
diff --git a/libgcc/unwind-dw2.c b/libgcc/unwind-dw2.c
index eaceace2029..c370121bb29 100644
--- a/libgcc/unwind-dw2.c
+++ b/libgcc/unwind-dw2.c
@@ -148,9 +148,25 @@ struct _Unwind_Context
char by_value[__LIBGCC_DWARF_FRAME_REGISTERS__+1];
};
+#ifdef __LIBGCC_DWARF_REG_SIZES_CONSTANT__
+static inline unsigned char
+dwarf_reg_size (int index __attribute__ ((__unused__)))
+{
+ return __LIBGCC_DWARF_REG_SIZES_CONSTANT__;
+}
+#else
/* Byte size of every register managed by these routines. */
static unsigned char dwarf_reg_size_table[__LIBGCC_DWARF_FRAME_REGISTERS__+1];
+
+static inline unsigned char
+dwarf_reg_size (unsigned index)
+{
+ gcc_assert (index < sizeof (dwarf_reg_size_table));
+ return dwarf_reg_size_table[index];
+}
+#endif
+
/* Read unaligned data from the instruction buffer. */
@@ -232,8 +248,7 @@ _Unwind_GetGR (struct _Unwind_Context *context, int regno)
#endif
index = DWARF_REG_TO_UNWIND_COLUMN (regno);
- gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
- size = dwarf_reg_size_table[index];
+ size = dwarf_reg_size (index);
val = context->reg[index];
if (_Unwind_IsExtendedContext (context) && context->by_value[index])
@@ -280,8 +295,7 @@ _Unwind_SetGR (struct _Unwind_Context *context, int index,
_Unwind_Word val)
void *ptr;
index = DWARF_REG_TO_UNWIND_COLUMN (index);
- gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
- size = dwarf_reg_size_table[index];
+ size = dwarf_reg_size (index);
if (_Unwind_IsExtendedContext (context) && context->by_value[index])
{
@@ -329,9 +343,8 @@ _Unwind_SetGRValue (struct _Unwind_Context *context, int
index,
_Unwind_Word val)
{
index = DWARF_REG_TO_UNWIND_COLUMN (index);
- gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
/* Return column size may be smaller than _Unwind_Context_Reg_Val. */
- gcc_assert (dwarf_reg_size_table[index] <= sizeof (_Unwind_Context_Reg_Val));
+ gcc_assert (dwarf_reg_size (index) <= sizeof (_Unwind_Context_Reg_Val));
context->by_value[index] = 1;
context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);
@@ -1387,7 +1400,7 @@ static inline void
_Unwind_SetSpColumn (struct _Unwind_Context *context, void *cfa,
_Unwind_SpTmp *tmp_sp)
{
- int size = dwarf_reg_size_table[__builtin_dwarf_sp_column ()];
+ int size = dwarf_reg_size (__builtin_dwarf_sp_column ());
if (size == sizeof(_Unwind_Ptr))
tmp_sp->ptr = (_Unwind_Ptr) cfa;
@@ -1573,11 +1586,13 @@ uw_advance_context (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
} \
while (0)
+#ifndef __LIBGCC_DWARF_REG_SIZES_CONSTANT__
static inline void
init_dwarf_reg_size_table (void)
{
__builtin_init_dwarf_reg_size_table (dwarf_reg_size_table);
}
+#endif
static void __attribute__((noinline))
uw_init_context_1 (struct _Unwind_Context *context,
@@ -1596,16 +1611,18 @@ uw_init_context_1 (struct _Unwind_Context *context,
code = uw_frame_state_for (context, &fs);
gcc_assert (code == _URC_NO_REASON);
-#if __GTHREADS
+#ifndef __LIBGCC_DWARF_REG_SIZES_CONSTANT__
+# if __GTHREADS
{
static __gthread_once_t once_regsizes = __GTHREAD_ONCE_INIT;
if (__gthread_once (&once_regsizes, init_dwarf_reg_size_table) != 0
&& dwarf_reg_size_table[0] == 0)
init_dwarf_reg_size_table ();
}
-#else
+# else
if (dwarf_reg_size_table[0] == 0)
init_dwarf_reg_size_table ();
+# endif
#endif
/* Force the frame state to use the known cfa value. */
@@ -1682,20 +1699,20 @@ uw_install_context_1 (struct _Unwind_Context *current,
{
_Unwind_Word w;
_Unwind_Ptr p;
- if (dwarf_reg_size_table[i] == sizeof (_Unwind_Word))
+ if (dwarf_reg_size (i) == sizeof (_Unwind_Word))
{
w = (_Unwind_Internal_Ptr) t;
memcpy (c, &w, sizeof (_Unwind_Word));
}
else
{
- gcc_assert (dwarf_reg_size_table[i] == sizeof (_Unwind_Ptr));
+ gcc_assert (dwarf_reg_size (i) == sizeof (_Unwind_Ptr));
p = (_Unwind_Internal_Ptr) t;
memcpy (c, &p, sizeof (_Unwind_Ptr));
}
}
else if (t && c && t != c)
- memcpy (c, t, dwarf_reg_size_table[i]);
+ memcpy (c, t, dwarf_reg_size (i));
}
/* If the current frame doesn't have a saved stack pointer, then we
--
2.38.1
