Move ASSERT() macro file text to PMEM (esp8266#3477)

Every assert() includes a __FILE__ constant string to RODATA which
can be quite large as it includes the complete path as well as
the filename.

Move that string into PMEM, and update the postmortem to work with
either PMEM or RAM strings for dumping abort/assert/exception
information.

cores/esp8266/core_esp8266_postmortem.c

@@ -27,12 +27,14 @@
 #include "user_interface.h"
 #include "esp8266_peri.h"
 #include "cont.h"
+#include "pgmspace.h"
 
 extern void __real_system_restart_local();
 extern void gdb_do_break();
 
 extern cont_t g_cont;
 
+// These will be pointers to PROGMEM const strings
 static const char* s_panic_file = 0;
 static int s_panic_line = 0;
 static const char* s_panic_func = 0;
@@ -55,6 +57,14 @@ extern void __custom_crash_callback( struct rst_info * rst_info, uint32_t stack,
 
 extern void custom_crash_callback( struct rst_info * rst_info, uint32_t stack, uint32_t stack_end ) __attribute__ ((weak, alias("__custom_crash_callback")));
 
+static void ets_puts_P(const char *romString) {
+    char c = pgm_read_byte(romString++);
+    while (c) {
+        ets_putc(c);
+        c = pgm_read_byte(romString++);
+    }
+}
+
 void __wrap_system_restart_local() {
     if (crash_for_gdb) *((int*)0) = 0;
     register uint32_t sp asm("a1");
@@ -71,17 +81,21 @@ void __wrap_system_restart_local() {
     ets_install_putc1(&uart_write_char_d);
 
     if (s_panic_line) {
-        ets_printf("\nPanic %s:%d %s\n", s_panic_file, s_panic_line, s_panic_func);
+        ets_puts_P(PSTR("\nPanic "));
+        ets_puts_P(s_panic_file);
+        ets_printf(":%d ", s_panic_line);
+        ets_puts_P(s_panic_func);
+        ets_puts_P(PSTR("\n"));
     }
     else if (s_abort_called) {
-        ets_printf("Abort called\n");
+        ets_puts_P(PSTR("Abort called\n"));
     }
     else if (rst_info.reason == REASON_EXCEPTION_RST) {
         ets_printf("\nException (%d):\nepc1=0x%08x epc2=0x%08x epc3=0x%08x excvaddr=0x%08x depc=0x%08x\n",
             rst_info.exccause, rst_info.epc1, rst_info.epc2, rst_info.epc3, rst_info.excvaddr, rst_info.depc);
     }
     else if (rst_info.reason == REASON_SOFT_WDT_RST) {
-        ets_printf("\nSoft WDT reset\n");
+        ets_puts_P(PSTR("\nSoft WDT reset\n"));
     }
 
     uint32_t cont_stack_start = (uint32_t) &(g_cont.stack);
@@ -103,11 +117,11 @@ void __wrap_system_restart_local() {
     }
 
     if (sp > cont_stack_start && sp < cont_stack_end) {
-        ets_printf("\nctx: cont \n");
+        ets_puts_P(PSTR("\nctx: cont \n"));
         stack_end = cont_stack_end;
     }
     else {
-        ets_printf("\nctx: sys \n");
+        ets_puts_P(("\nctx: sys \n"));
         stack_end = 0x3fffffb0;
         // it's actually 0x3ffffff0, but the stuff below ets_run
         // is likely not really relevant to the crash
@@ -126,7 +140,7 @@ void __wrap_system_restart_local() {
 
 
 static void print_stack(uint32_t start, uint32_t end) {
-    ets_printf("\n>>>stack>>>\n");
+    ets_puts_P(PSTR("\n>>>stack>>>\n"));
     for (uint32_t pos = start; pos < end; pos += 0x10) {
         uint32_t* values = (uint32_t*)(pos);
 
@@ -136,7 +150,7 @@ static void print_stack(uint32_t start, uint32_t end) {
         ets_printf("%08x:  %08x %08x %08x %08x %c\n",
             pos, values[0], values[1], values[2], values[3], (looksLikeStackFrame)?'<':' ');
     }
-    ets_printf("<<<stack<<<\n");
+    ets_puts_P(PSTR("<<<stack<<<\n"));
 }
 
 /*

tools/sdk/libc/xtensa-lx106-elf/include/assert.h

@@ -7,13 +7,14 @@ extern "C" {
 #endif
 
 #include "_ansi.h"
+#include <pgmspace.h>
 
 #undef assert
 
 #ifdef NDEBUG           /* required by ANSI standard */
 # define assert(__e) ((void)0)
 #else
-# define assert(__e) ((__e) ? (void)0 : __assert_func (__FILE__, __LINE__, \
+# define assert(__e) ((__e) ? (void)0 : __assert_func (PSTR(__FILE__), __LINE__, \
 						       __ASSERT_FUNC, #__e))
 
 # ifndef __ASSERT_FUNC