Force inlining of inline print[ln] methods

Add GCC __attribute__ ((__always_inline__)) to inlined methods in Print.h.
This seems necessary since not doing so increases the executable size
(probably because that would create several function definitions),
even with LTO optimizations.
This change combined with the inlining of print/printf methods seems to reduce
the executable size for most applications by a fair amount.
(Note that the `inline` keyword does not imply actual inlining.)

Author: cousteaulecommandant

Diff for: hardware/arduino/avr/cores/arduino/Print.h

@@ -31,6 +31,8 @@
 #define OCT 8
 #define BIN 2
 
+#define _always_inline __attribute__ ((__always_inline__)) // undefined at end
+
 class Print
 {
   private:
@@ -61,22 +63,24 @@ class Print
     size_t print(unsigned long, int = DEC);
     size_t print(double, int = 2);
 
-    size_t print(const char str[])   { return write(str); }
-    size_t print(const char c)       { return write(c); }
-    size_t print(const Printable &x) { return x.printTo(*this); }
+    _always_inline size_t print(const char str[])   { return write(str); }
+    _always_inline size_t print(const char c)       { return write(c); }
+    _always_inline size_t print(const Printable &x) { return x.printTo(*this); }
 
-    size_t print(  signed char  n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(  signed short n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(  signed int   n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(unsigned char  n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(unsigned short n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(unsigned int   n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(    float      n, int f = 2  ) { return print((    double   ) n, f); }
+    _always_inline size_t print(  signed char  n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(  signed short n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(  signed int   n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(unsigned char  n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(unsigned short n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(unsigned int   n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(    float      n, int f = 2  ) { return print((    double   ) n, f); }
 
     size_t println(void);
 
-    template<typename T> size_t println(const T &arg)      { size_t t = print(arg);  return t + println(); }
-    template<typename T> size_t println(const T &n, int f) { size_t t = print(n, f); return t + println(); }
+    template<typename T> _always_inline size_t println(const T &arg)      { size_t t = print(arg);  return t + println(); }
+    template<typename T> _always_inline size_t println(const T &n, int f) { size_t t = print(n, f); return t + println(); }
 };
 
+#undef _always_inline
+
 #endif

Diff for: hardware/arduino/sam/cores/arduino/Print.h

@@ -31,6 +31,8 @@
 #define OCT 8
 #define BIN 2
 
+#define _always_inline __attribute__ ((__always_inline__)) // undefined at end
+
 class Print
 {
   private:
@@ -61,22 +63,24 @@ class Print
     size_t print(unsigned long, int = DEC);
     size_t print(double, int = 2);
 
-    size_t print(const char str[])   { return write(str); }
-    size_t print(const char c)       { return write(c); }
-    size_t print(const Printable &x) { return x.printTo(*this); }
+    _always_inline size_t print(const char str[])   { return write(str); }
+    _always_inline size_t print(const char c)       { return write(c); }
+    _always_inline size_t print(const Printable &x) { return x.printTo(*this); }
 
-    size_t print(  signed char  n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(  signed short n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(  signed int   n, int f = DEC) { return print((  signed long) n, f); }
-    size_t print(unsigned char  n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(unsigned short n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(unsigned int   n, int f = DEC) { return print((unsigned long) n, f); }
-    size_t print(    float      n, int f = 2  ) { return print((    double   ) n, f); }
+    _always_inline size_t print(  signed char  n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(  signed short n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(  signed int   n, int f = DEC) { return print((  signed long) n, f); }
+    _always_inline size_t print(unsigned char  n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(unsigned short n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(unsigned int   n, int f = DEC) { return print((unsigned long) n, f); }
+    _always_inline size_t print(    float      n, int f = 2  ) { return print((    double   ) n, f); }
 
     size_t println(void);
 
-    template<typename T> size_t println(const T &arg)      { size_t t = print(arg);  return t + println(); }
-    template<typename T> size_t println(const T &n, int f) { size_t t = print(n, f); return t + println(); }
+    template<typename T> _always_inline size_t println(const T &arg)      { size_t t = print(arg);  return t + println(); }
+    template<typename T> _always_inline size_t println(const T &n, int f) { size_t t = print(n, f); return t + println(); }
 };
 
+#undef _always_inline
+
 #endif