diff mbox

Fix compilation errors with libstdc++v3 for AVR target and allow --enable-libstdcxx

Message ID CADfx-VTnMiG=b7yBKPXxO=ATrEBJ=1O5HEEVN2jMz_J-ExESRA@mail.gmail.com
State New
Headers show

Commit Message

Felipe Magno de Almeida Nov. 10, 2016, 3:51 p.m. UTC 
On Thu, Nov 10, 2016 at 1:39 PM, Felipe Magno de Almeida
<felipe.m.almeida@gmail.com> wrote:
> Hello,

>

> Sorry for top-posting, but this is a ping for the attached patch.

>

> The patch doesn't seem to have been applied nor refused. So I'm

> pinging to see if I need to change something? I already have a

> copyright assignment now.

>

> I'm attaching a updated patch that doesn't conflict in the Changelog

> file.


Reattaching the patch with the correct git commit descriptions.

> Regards,


[snip]

> --

> Felipe Magno de Almeida


Kind regards,
-- 
Felipe Magno de Almeida

Comments

Jonathan Wakely Dec. 6, 2016, 3:08 p.m. UTC | #1 
On 10/11/16 13:51 -0200, Felipe Magno de Almeida wrote:
>--- a/libstdc++-v3/include/bits/locale_facets_nonio.tcc

>+++ b/libstdc++-v3/include/bits/locale_facets_nonio.tcc

>@@ -659,30 +659,38 @@ _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11

> 		  // Abbreviated weekday name [tm_wday]

> 		  const char_type*  __days1[7];

> 		  __tp._M_days_abbreviated(__days1);

>-		  __beg = _M_extract_name(__beg, __end, __tm->tm_wday, __days1,

>+                  __tm->tm_wday = __mem;

>+		  __beg = _M_extract_name(__beg, __end, __mem, __days1,

> 					  7, __io, __tmperr);

>+                  __mem = __tm->tm_wday;

> 		  break;


Isn't this backwards?

You assign a garbage value to tm_wday, read into __mem, then assign
the garbage back to it.

Has this change been tested?
Jonathan Wakely Dec. 6, 2016, 5:59 p.m. UTC | #2 
On 10/11/16 13:51 -0200, Felipe Magno de Almeida wrote:
>Subject: [PATCH 1/3] Add #ifdef case for 16 bits in cow-stdexcept.cc

>

>Added #ifdef case for when void* is 16 bits so it compiles in AVR

>target.


I've committed this patch.

>From 7ed4af72fe0bdee1a38c7487955590fb64f76a5d Mon Sep 17 00:00:00 2001

>From: Felipe Magno de Almeida <felipe@expertisesolutions.com.br>

>Date: Thu, 15 Sep 2016 18:52:57 -0300

>Subject: [PATCH 2/3] Use temporary int objects to access struct tm members

>

>Call _M_extract_* functions family through temporary int objects, so

>it doesn't convert from lvalue to rvalue through a temporary in AVR

>because of the incompatible types used in AVR-Libc.

>

>This fixes compilation errors with AVR-Libc while compiling libstdc++

>for AVR target.


This one has problems, see my earlier email.


>Subject: [PATCH 3/3] Enable libstdc++ compilation in AVR targets

>

>Enable libstdc++ compilation in AVR targets with AVR-Libc. Most

>floating point math functions are already defined in AVR-Libc, so

>defines are in place to avoid multiple definition of these functions.


I've committed this one too.
Jonathan Wakely Dec. 6, 2016, 6:11 p.m. UTC | #3 
On 10/11/16 13:51 -0200, Felipe Magno de Almeida wrote:
>@@ -752,11 +770,13 @@ _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11

> 		  // Seconds. [tm_sec]

> 		  // [00, 60] in C99 (one leap-second), [00, 61] in C89.

> #if _GLIBCXX_USE_C99

>-		  __beg = _M_extract_num(__beg, __end, __tm->tm_sec, 0, 60, 2,

>+                  __mem = __tm->tm_sec;

>+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 60, 2,

> #else

>-		  __beg = _M_extract_num(__beg, __end, __tm->tm_sec, 0, 61, 2,

>+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 61, 2,

> #endif

> 					 __io, __tmperr);

>+                  __tm->tm_sec = __mem;

> 		  break;

> 		case 't':

> 		  if (__ctype.narrow(*__beg, 0) == '\t')


This part looks wrong too. The assignment to __mem should be outside
the #if condition.
Jonathan Wakely Sept. 29, 2023, 2:07 p.m. UTC | #4 
On Tue, 6 Dec 2016 at 17:59, Jonathan Wakely wrote:
> >Subject: [PATCH 3/3] Enable libstdc++ compilation in AVR targets
> >
> >Enable libstdc++ compilation in AVR targets with AVR-Libc. Most
> >floating point math functions are already defined in AVR-Libc, so
> >defines are in place to avoid multiple definition of these functions.
>
> I've committed this one too.


Hi Felipe,

Back in 2006 we committed a patch from you that made this change:

--- a/libstdc++-v3/crossconfig.m4
+++ b/libstdc++-v3/crossconfig.m4
@@ -9,6 +9,32 @@ case "${host}" in
     # This is a freestanding configuration; there is nothing to do here.
     ;;

+  avr*-*-*)
+    AC_DEFINE(HAVE_ACOSF)
+    AC_DEFINE(HAVE_ASINF)
+    AC_DEFINE(HAVE_ATAN2F)
+    AC_DEFINE(HAVE_ATANF)
+    AC_DEFINE(HAVE_CEILF)
+    AC_DEFINE(HAVE_COSF)
+    AC_DEFINE(HAVE_COSHF)
+    AC_DEFINE(HAVE_EXPF)
+    AC_DEFINE(HAVE_FABSF)
+    AC_DEFINE(HAVE_FLOORF)
+    AC_DEFINE(HAVE_FMODF)
+    AC_DEFINE(HAVE_FREXPF)
+    AC_DEFINE(HAVE_SQRTF)
+    AC_DEFINE(HAVE_HYPOTF)
+    AC_DEFINE(HAVE_LDEXPF)
+    AC_DEFINE(HAVE_LOG10F)
+    AC_DEFINE(HAVE_LOGF)
+    AC_DEFINE(HAVE_MODFF)
+    AC_DEFINE(HAVE_POWF)
+    AC_DEFINE(HAVE_SINF)
+    AC_DEFINE(HAVE_SINHF)
+    AC_DEFINE(HAVE_TANF)
+    AC_DEFINE(HAVE_TANHF)
+    ;;
+
   mips*-sde-elf*)
     # These definitions are for the SDE C library rather than newlib.
     SECTION_FLAGS='-ffunction-sections -fdata-sections'

I'm testing a change today which causes a build failure on avr,
because of your config change.

I've filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111639 about
this, could you take a look please?

You said that AVR has those math functions, so we don't need to define
them in libstdc++-v3/src/c++98/math_stubs_float.cc but I don't think
that's true. It doesn't have them, it has macros like this:

extern double acos(double __x) __ATTR_CONST__;
#define acosf    acos        /**< The alias for acos().    */

That does indeed cause build failures in math_stubs_float.cc, but not
because of duplicate definitions of acosf etc.

And the macro definitions are not acceptable definitions of those
functions for a C++ library.

I've proposed a fix in the bug report.
Jonathan Wakely Sept. 29, 2023, 2:30 p.m. UTC | #5 
On Fri, 29 Sept 2023 at 15:07, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Tue, 6 Dec 2016 at 17:59, Jonathan Wakely wrote:
> > >Subject: [PATCH 3/3] Enable libstdc++ compilation in AVR targets
> > >
> > >Enable libstdc++ compilation in AVR targets with AVR-Libc. Most
> > >floating point math functions are already defined in AVR-Libc, so
> > >defines are in place to avoid multiple definition of these functions.
> >
> > I've committed this one too.
>
>
> Hi Felipe,
>
> Back in 2006 we committed a patch from you that made this change:

Oops, sorry for the typo, I meant 2016 of course!


>
> --- a/libstdc++-v3/crossconfig.m4
> +++ b/libstdc++-v3/crossconfig.m4
> @@ -9,6 +9,32 @@ case "${host}" in
>      # This is a freestanding configuration; there is nothing to do here.
>      ;;
>
> +  avr*-*-*)
> +    AC_DEFINE(HAVE_ACOSF)
> +    AC_DEFINE(HAVE_ASINF)
> +    AC_DEFINE(HAVE_ATAN2F)
> +    AC_DEFINE(HAVE_ATANF)
> +    AC_DEFINE(HAVE_CEILF)
> +    AC_DEFINE(HAVE_COSF)
> +    AC_DEFINE(HAVE_COSHF)
> +    AC_DEFINE(HAVE_EXPF)
> +    AC_DEFINE(HAVE_FABSF)
> +    AC_DEFINE(HAVE_FLOORF)
> +    AC_DEFINE(HAVE_FMODF)
> +    AC_DEFINE(HAVE_FREXPF)
> +    AC_DEFINE(HAVE_SQRTF)
> +    AC_DEFINE(HAVE_HYPOTF)
> +    AC_DEFINE(HAVE_LDEXPF)
> +    AC_DEFINE(HAVE_LOG10F)
> +    AC_DEFINE(HAVE_LOGF)
> +    AC_DEFINE(HAVE_MODFF)
> +    AC_DEFINE(HAVE_POWF)
> +    AC_DEFINE(HAVE_SINF)
> +    AC_DEFINE(HAVE_SINHF)
> +    AC_DEFINE(HAVE_TANF)
> +    AC_DEFINE(HAVE_TANHF)
> +    ;;
> +
>    mips*-sde-elf*)
>      # These definitions are for the SDE C library rather than newlib.
>      SECTION_FLAGS='-ffunction-sections -fdata-sections'
>
> I'm testing a change today which causes a build failure on avr,
> because of your config change.
>
> I've filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111639 about
> this, could you take a look please?
>
> You said that AVR has those math functions, so we don't need to define
> them in libstdc++-v3/src/c++98/math_stubs_float.cc but I don't think
> that's true. It doesn't have them, it has macros like this:
>
> extern double acos(double __x) __ATTR_CONST__;
> #define acosf    acos        /**< The alias for acos().    */
>
> That does indeed cause build failures in math_stubs_float.cc, but not
> because of duplicate definitions of acosf etc.
>
> And the macro definitions are not acceptable definitions of those
> functions for a C++ library.
>
> I've proposed a fix in the bug report.
diff mbox

Patch

From 2e62f3a4b3c307e2abec0cb0302ec601b8f693e8 Mon Sep 17 00:00:00 2001
From: Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
Date: Thu, 15 Sep 2016 15:54:50 -0300
Subject: [PATCH 1/3] Add #ifdef case for 16 bits in cow-stdexcept.cc

Added #ifdef case for when void* is 16 bits so it compiles in AVR
target.
---
 libstdc++-v3/ChangeLog                  |  4 ++++
 libstdc++-v3/src/c++11/cow-stdexcept.cc | 11 ++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index f405ccd..80d2e9d 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,7 @@ 
+2016-11-10  Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
+
+	* src/c++11/cow-stdexcept.cc: Add special case for 16 bit pointers
+
 2016-11-09  Tim Shen  <timshen@google.com>
 
 	* libstdc++-v3/include/bits/regex.h (regex_iterator::regex_iterator()):
diff --git a/libstdc++-v3/src/c++11/cow-stdexcept.cc b/libstdc++-v3/src/c++11/cow-stdexcept.cc
index 31a89df..641b372 100644
--- a/libstdc++-v3/src/c++11/cow-stdexcept.cc
+++ b/libstdc++-v3/src/c++11/cow-stdexcept.cc
@@ -208,6 +208,8 @@  extern void* _ZGTtnaX (size_t sz) __attribute__((weak));
 extern void _ZGTtdlPv (void* ptr) __attribute__((weak));
 extern uint8_t _ITM_RU1(const uint8_t *p)
   ITM_REGPARM __attribute__((weak));
+extern uint16_t _ITM_RU2(const uint16_t *p)
+  ITM_REGPARM __attribute__((weak));
 extern uint32_t _ITM_RU4(const uint32_t *p)
   ITM_REGPARM __attribute__((weak));
 extern uint64_t _ITM_RU8(const uint64_t *p)
@@ -272,12 +274,15 @@  _txnal_cow_string_C1_for_exceptions(void* that, const char* s,
 static void* txnal_read_ptr(void* const * ptr)
 {
   static_assert(sizeof(uint64_t) == sizeof(void*)
-		|| sizeof(uint32_t) == sizeof(void*),
-		"Pointers must be 32 bits or 64 bits wide");
+		|| sizeof(uint32_t) == sizeof(void*)
+		|| sizeof(uint16_t) == sizeof(void*),
+		"Pointers must be 16 bits, 32 bits or 64 bits wide");
 #if __UINTPTR_MAX__ == __UINT64_MAX__
   return (void*)_ITM_RU8((const uint64_t*)ptr);
-#else
+#elif __UINTPTR_MAX__ == __UINT32_MAX__
   return (void*)_ITM_RU4((const uint32_t*)ptr);
+#else
+  return (void*)_ITM_RU2((const uint16_t*)ptr);
 #endif
 }
 
-- 
2.10.2


From 7ed4af72fe0bdee1a38c7487955590fb64f76a5d Mon Sep 17 00:00:00 2001
From: Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
Date: Thu, 15 Sep 2016 18:52:57 -0300
Subject: [PATCH 2/3] Use temporary int objects to access struct tm members

Call _M_extract_* functions family through temporary int objects, so
it doesn't convert from lvalue to rvalue through a temporary in AVR
because of the incompatible types used in AVR-Libc.

This fixes compilation errors with AVR-Libc while compiling libstdc++
for AVR target.
---
 libstdc++-v3/ChangeLog                            |  5 +++
 libstdc++-v3/include/bits/locale_facets_nonio.tcc | 44 ++++++++++++++++-------
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 80d2e9d..80c75c6 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@ 
 2016-11-10  Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
 
+	* include/bits/locale_facets_nonio.tcc: Avoid compilation errors
+	with non-standard struct tm.
+
+2016-11-10  Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
+
 	* src/c++11/cow-stdexcept.cc: Add special case for 16 bit pointers
 
 2016-11-09  Tim Shen  <timshen@google.com>
diff --git a/libstdc++-v3/include/bits/locale_facets_nonio.tcc b/libstdc++-v3/include/bits/locale_facets_nonio.tcc
index 1a4f9a0..cc9d2df 100644
--- a/libstdc++-v3/include/bits/locale_facets_nonio.tcc
+++ b/libstdc++-v3/include/bits/locale_facets_nonio.tcc
@@ -659,30 +659,38 @@  _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
 		  // Abbreviated weekday name [tm_wday]
 		  const char_type*  __days1[7];
 		  __tp._M_days_abbreviated(__days1);
-		  __beg = _M_extract_name(__beg, __end, __tm->tm_wday, __days1,
+                  __tm->tm_wday = __mem;
+		  __beg = _M_extract_name(__beg, __end, __mem, __days1,
 					  7, __io, __tmperr);
+                  __mem = __tm->tm_wday;
 		  break;
 		case 'A':
 		  // Weekday name [tm_wday].
 		  const char_type*  __days2[7];
 		  __tp._M_days(__days2);
-		  __beg = _M_extract_name(__beg, __end, __tm->tm_wday, __days2,
+                  __mem = __tm->tm_wday;
+		  __beg = _M_extract_name(__beg, __end, __mem, __days2,
 					  7, __io, __tmperr);
+                  __tm->tm_wday = __mem;
 		  break;
 		case 'h':
 		case 'b':
 		  // Abbreviated month name [tm_mon]
 		  const char_type*  __months1[12];
 		  __tp._M_months_abbreviated(__months1);
-		  __beg = _M_extract_name(__beg, __end, __tm->tm_mon, 
+                  __mem = __tm->tm_mon;
+		  __beg = _M_extract_name(__beg, __end, __mem, 
 					  __months1, 12, __io, __tmperr);
+                  __tm->tm_mon = __mem;
 		  break;
 		case 'B':
 		  // Month name [tm_mon].
 		  const char_type*  __months2[12];
 		  __tp._M_months(__months2);
-		  __beg = _M_extract_name(__beg, __end, __tm->tm_mon, 
+                  __mem = __tm->tm_mon;
+		  __beg = _M_extract_name(__beg, __end, __mem, 
 					  __months2, 12, __io, __tmperr);
+                  __tm->tm_mon = __mem;
 		  break;
 		case 'c':
 		  // Default time and date representation.
@@ -693,18 +701,22 @@  _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
 		  break;
 		case 'd':
 		  // Day [01, 31]. [tm_mday]
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_mday, 1, 31, 2,
+                  __mem = __tm->tm_mday;
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 31, 2,
 					 __io, __tmperr);
+                  __tm->tm_mday = __mem;
 		  break;
 		case 'e':
 		  // Day [1, 31], with single digits preceded by
 		  // space. [tm_mday]
+                  __mem = __tm->tm_mday;
 		  if (__ctype.is(ctype_base::space, *__beg))
-		    __beg = _M_extract_num(++__beg, __end, __tm->tm_mday, 1, 9,
+		    __beg = _M_extract_num(++__beg, __end, __mem, 1, 9,
 					   1, __io, __tmperr);
 		  else
-		    __beg = _M_extract_num(__beg, __end, __tm->tm_mday, 10, 31,
+		    __beg = _M_extract_num(__beg, __end, __mem, 10, 31,
 					   2, __io, __tmperr);
+                  __tm->tm_mday = __mem;
 		  break;
 		case 'D':
 		  // Equivalent to %m/%d/%y.[tm_mon, tm_mday, tm_year]
@@ -715,13 +727,17 @@  _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
 		  break;
 		case 'H':
 		  // Hour [00, 23]. [tm_hour]
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_hour, 0, 23, 2,
+                  __mem = __tm->tm_hour;
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 23, 2,
 					 __io, __tmperr);
+                  __tm->tm_hour = __mem;
 		  break;
 		case 'I':
 		  // Hour [01, 12]. [tm_hour]
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_hour, 1, 12, 2,
+                  __mem = __tm->tm_hour;
+		  __beg = _M_extract_num(__beg, __end, __mem, 1, 12, 2,
 					 __io, __tmperr);
+                  __tm->tm_hour = __mem;
 		  break;
 		case 'm':
 		  // Month [01, 12]. [tm_mon]
@@ -732,8 +748,10 @@  _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
 		  break;
 		case 'M':
 		  // Minute [00, 59]. [tm_min]
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_min, 0, 59, 2,
+                  __mem = __tm->tm_min;
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 59, 2,
 					 __io, __tmperr);
+                  __tm->tm_min = __mem;
 		  break;
 		case 'n':
 		  if (__ctype.narrow(*__beg, 0) == '\n')
@@ -752,11 +770,13 @@  _GLIBCXX_END_NAMESPACE_LDBL_OR_CXX11
 		  // Seconds. [tm_sec]
 		  // [00, 60] in C99 (one leap-second), [00, 61] in C89.
 #if _GLIBCXX_USE_C99
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_sec, 0, 60, 2,
+                  __mem = __tm->tm_sec;
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 60, 2,
 #else
-		  __beg = _M_extract_num(__beg, __end, __tm->tm_sec, 0, 61, 2,
+		  __beg = _M_extract_num(__beg, __end, __mem, 0, 61, 2,
 #endif
 					 __io, __tmperr);
+                  __tm->tm_sec = __mem;
 		  break;
 		case 't':
 		  if (__ctype.narrow(*__beg, 0) == '\t')
-- 
2.10.2


From 5bec19a49d6ae7e18327bb1b323275f78ef5aa42 Mon Sep 17 00:00:00 2001
From: Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
Date: Thu, 15 Sep 2016 16:05:02 -0300
Subject: [PATCH 3/3] Enable libstdc++ compilation in AVR targets

Enable libstdc++ compilation in AVR targets with AVR-Libc. Most
floating point math functions are already defined in AVR-Libc, so
defines are in place to avoid multiple definition of these functions.
---
 libstdc++-v3/ChangeLog      |  5 +++++
 libstdc++-v3/configure      | 49 +++++++++++++++++++++++++++++++++++++++++++++
 libstdc++-v3/crossconfig.m4 | 26 ++++++++++++++++++++++++
 3 files changed, 80 insertions(+)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 80c75c6..ca2736f 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@ 
 2016-11-10  Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
 
+	* crossconfig.m4: Add avr target for cross-compilation
+	* configure: Regenerate
+
+2016-11-10  Felipe Magno de Almeida <felipe@expertisesolutions.com.br>
+
 	* include/bits/locale_facets_nonio.tcc: Avoid compilation errors
 	with non-standard struct tm.
 
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 8481a48..5e3f783 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -28840,6 +28840,55 @@  case "${host}" in
     # This is a freestanding configuration; there is nothing to do here.
     ;;
 
+  avr*-*-*)
+    $as_echo "#define HAVE_ACOSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ASINF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ATAN2F 1" >>confdefs.h
+
+    $as_echo "#define HAVE_ATANF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_CEILF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_COSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_COSHF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_EXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FABSF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FLOORF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FMODF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_FREXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SQRTF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_HYPOTF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LDEXPF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LOG10F 1" >>confdefs.h
+
+    $as_echo "#define HAVE_LOGF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_MODFF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_POWF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SINF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_SINHF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_TANF 1" >>confdefs.h
+
+    $as_echo "#define HAVE_TANHF 1" >>confdefs.h
+
+    ;;
+
   mips*-sde-elf*)
     # These definitions are for the SDE C library rather than newlib.
     SECTION_FLAGS='-ffunction-sections -fdata-sections'
diff --git a/libstdc++-v3/crossconfig.m4 b/libstdc++-v3/crossconfig.m4
index 6abc84f..2b955ec 100644
--- a/libstdc++-v3/crossconfig.m4
+++ b/libstdc++-v3/crossconfig.m4
@@ -9,6 +9,32 @@  case "${host}" in
     # This is a freestanding configuration; there is nothing to do here.
     ;;
 
+  avr*-*-*)
+    AC_DEFINE(HAVE_ACOSF)
+    AC_DEFINE(HAVE_ASINF)
+    AC_DEFINE(HAVE_ATAN2F)
+    AC_DEFINE(HAVE_ATANF)
+    AC_DEFINE(HAVE_CEILF)
+    AC_DEFINE(HAVE_COSF)
+    AC_DEFINE(HAVE_COSHF)
+    AC_DEFINE(HAVE_EXPF)
+    AC_DEFINE(HAVE_FABSF)
+    AC_DEFINE(HAVE_FLOORF)
+    AC_DEFINE(HAVE_FMODF)
+    AC_DEFINE(HAVE_FREXPF)
+    AC_DEFINE(HAVE_SQRTF)
+    AC_DEFINE(HAVE_HYPOTF)
+    AC_DEFINE(HAVE_LDEXPF)
+    AC_DEFINE(HAVE_LOG10F)
+    AC_DEFINE(HAVE_LOGF)
+    AC_DEFINE(HAVE_MODFF)
+    AC_DEFINE(HAVE_POWF)
+    AC_DEFINE(HAVE_SINF)
+    AC_DEFINE(HAVE_SINHF)
+    AC_DEFINE(HAVE_TANF)
+    AC_DEFINE(HAVE_TANHF)
+    ;;
+
   mips*-sde-elf*)
     # These definitions are for the SDE C library rather than newlib.
     SECTION_FLAGS='-ffunction-sections -fdata-sections'
-- 
2.10.2