From cde452e270e500db776e75d0bdda0b32d9c37981 Mon Sep 17 00:00:00 2001
From: Georg-Johann Lay <avr@gjlay.de>
Date: Thu, 30 Jan 2025 12:05:19 +0100
Subject: [PATCH] AVR: Only provide a built-in when it is available.
Some built-ins are not available for C++ since they are using
named address-spaces or fixed-point types.
gcc/
* config/avr/builtins.def (AVR_FIRST_C_ONLY_BUILTIN_ID): New macro.
* config/avr/avr-protos.h (avr_builtin_supported_p): New.
* config/avr/avr.cc (avr_builtin_supported_p): New function.
(avr_init_builtins): Only provide a built-in when it is supported.
* config/avr/avr-c.cc (avr_cpu_cpp_builtins): Only define the
__BUILTIN_AVR_<NAME> build-in defines when the associated built-in
function is supported.
* doc/extend.texi (AVR Built-in Functions): Add a note that
following built-ins are supported for only for GNU-C.
---
gcc/config/avr/avr-c.cc | 3 ++-
gcc/config/avr/avr-protos.h | 1 +
gcc/config/avr/avr.cc | 25 ++++++++++++++++++++++---
gcc/config/avr/builtins.def | 7 +++++++
gcc/doc/extend.texi | 18 ++++++++++--------
5 files changed, 42 insertions(+), 12 deletions(-)
diff --git a/gcc/config/avr/avr-c.cc b/gcc/config/avr/avr-c.cc
index 53f15f2be7b3..f4236555bf6c 100644
--- a/gcc/config/avr/avr-c.cc
+++ b/gcc/config/avr/avr-c.cc
@@ -500,7 +500,8 @@ avr_cpu_cpp_builtins (cpp_reader *pfile)
not a specific builtin is available. */
#define DEF_BUILTIN(NAME, N_ARGS, TYPE, CODE, LIBNAME, ATTRS) \
- cpp_define (pfile, "__BUILTIN_AVR_" #NAME);
+ if (avr_builtin_supported_p (AVR_BUILTIN_ ## NAME)) \
+ cpp_define (pfile, "__BUILTIN_AVR_" #NAME);
#include "builtins.def"
#undef DEF_BUILTIN
diff --git a/gcc/config/avr/avr-protos.h b/gcc/config/avr/avr-protos.h
index 83137c7f6f63..6f37c48143ec 100644
--- a/gcc/config/avr/avr-protos.h
+++ b/gcc/config/avr/avr-protos.h
@@ -21,6 +21,7 @@
extern bool avr_function_arg_regno_p (int r);
extern void avr_cpu_cpp_builtins (cpp_reader * pfile);
+extern bool avr_builtin_supported_p (unsigned id);
extern enum reg_class avr_regno_reg_class (int r);
extern void asm_globalize_label (FILE *file, const char *name);
extern void avr_adjust_reg_alloc_order (void);
diff --git a/gcc/config/avr/avr.cc b/gcc/config/avr/avr.cc
index 656d3e7389b4..2b550e7761c8 100644
--- a/gcc/config/avr/avr.cc
+++ b/gcc/config/avr/avr.cc
@@ -15689,6 +15689,24 @@ avr_bdesc[AVR_BUILTIN_COUNT] =
};
+/* Some of our built-in function are available for GNU-C only:
+ - Built-ins that use named address-spaces.
+ - Built-ins that use fixed-point types. */
+
+bool
+avr_builtin_supported_p (unsigned id)
+{
+ const bool uses_as = id == AVR_BUILTIN_FLASH_SEGMENT;
+
+ // We don't support address-spaces on Reduced Tiny.
+ if (AVR_TINY && uses_as)
+ return false;
+
+ return (lang_GNU_C ()
+ || id < AVR_FIRST_C_ONLY_BUILTIN_ID);
+}
+
+
/* Implement `TARGET_BUILTIN_DECL'. */
static tree
@@ -15891,9 +15909,10 @@ avr_init_builtins (void)
char *name = (char *) alloca (1 + strlen (Name)); \
\
gcc_assert (id < AVR_BUILTIN_COUNT); \
- avr_bdesc[id].fndecl \
- = add_builtin_function (avr_tolower (name, Name), TYPE, id, \
- BUILT_IN_MD, LIBNAME, ATTRS); \
+ avr_bdesc[id].fndecl = avr_builtin_supported_p (id) \
+ ? add_builtin_function (avr_tolower (name, Name), TYPE, id, \
+ BUILT_IN_MD, LIBNAME, ATTRS) \
+ : NULL_TREE; \
}
#include "builtins.def"
#undef DEF_BUILTIN
diff --git a/gcc/config/avr/builtins.def b/gcc/config/avr/builtins.def
index 61dbc3a6c1be..ad75fe9c267c 100644
--- a/gcc/config/avr/builtins.def
+++ b/gcc/config/avr/builtins.def
@@ -34,6 +34,8 @@
ATTRS: Function attributes like "attr_const" for the `const' attribute
or "NULL_TREE" for no attribute. */
+#define AVR_FIRST_C_ONLY_BUILTIN_ID AVR_BUILTIN_FLASH_SEGMENT
+
/* Mapped to respective instruction. */
DEF_BUILTIN (NOP, -1, void_ftype_void, nothing, NULL, NULL_TREE)
@@ -56,6 +58,11 @@ DEF_BUILTIN (DELAY_CYCLES, -1, void_ftype_uintSI, nothing, NULL, NULL_TREE)
DEF_BUILTIN (NOPS, -1, void_ftype_uintSI, nothing, NULL, NULL_TREE)
DEF_BUILTIN (MASK1, 2, uintQI_ftype_uintQI_uintQI, gen_mask1, NULL, attr_const)
DEF_BUILTIN (INSERT_BITS, 3, uintQI_ftype_uintSI_uintQI_uintQI, insert_bits, NULL, attr_const)
+
+/* All following built-ins are C only, see avr.cc::avr_builtin_C_only_p()
+ * since they are using named address-spaces or fixed-point types, none
+ * of which are supported for C++. */
+
DEF_BUILTIN (FLASH_SEGMENT, 1, intQI_ftype_const_memx_ptr, flash_segment, NULL, attr_const)
/* ISO/IEC TR 18037 "Embedded C"
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 2764597a479b..c6e7bc37f7dc 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -17369,14 +17369,6 @@ might increase delay time. @var{ticks} must be a compile-time
integer constant; delays with a variable number of cycles are not supported.
@enddefbuiltin
-@defbuiltin{int8_t __builtin_avr_flash_segment (const __memx void*)}
-This built-in takes a byte address to the 24-bit
-@ref{AVR Named Address Spaces,address space} @code{__memx} and returns
-the number of the flash segment (the 64 KiB chunk) where the address
-points to. Counting starts at @code{0}.
-If the address does not point to flash memory, return @code{-1}.
-@enddefbuiltin
-
@defbuiltin{uint8_t __builtin_avr_insert_bits (uint32_t @var{map}, uint8_t @var{bits}, uint8_t @var{val})}
Insert bits from @var{bits} into @var{val} and return the resulting
value. The nibbles of @var{map} determine how the insertion is
@@ -17445,6 +17437,16 @@ Insert @var{count} @code{NOP} instructions.
The number of instructions must be a compile-time integer constant.
@enddefbuiltin
+@b{All of the following built-in functions are only available for GNU-C}
+
+@defbuiltin{int8_t __builtin_avr_flash_segment (const __memx void*)}
+This built-in takes a byte address to the 24-bit
+@ref{AVR Named Address Spaces,named address space} @code{__memx} and returns
+the number of the flash segment (the 64 KiB chunk) where the address
+points to. Counting starts at @code{0}.
+If the address does not point to flash memory, return @code{-1}.
+@enddefbuiltin
+
@noindent
There are many more AVR-specific built-in functions that are used to
implement the ISO/IEC TR 18037 ``Embedded C'' fixed-point functions of
--
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