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[PATCH FT32]: apply unbias to references to RAM symbols


The FT32 binutils use a bias to distinguish between RAM and flash
addresses.

This fix adds an ASM_OUTPUT_SYMBOL_REF() that unbiases references to
RAM symbols.

Only references to RAM objects have the bias applied. Flash objects
(that is, objects in ADDR SPACE 1) are not biased, so for these no bias
should be applied. Likewise references in the gdb section need to use
the biased address, so references in debug sections are not unbiased.

gcc/ChangeLog:

2016-07-08  James Bowman  <james.bowman@ftdichip.com>

	* config/ft32/ft32.c (ft32_elf_encode_section_info): New function.
	* config/ft32/ft32.h (ASM_OUTPUT_SYMBOL_REF): New function.

Index: gcc/config/ft32/ft32.c
===================================================================
--- gcc/config/ft32/ft32.c	(revision 237998)
+++ gcc/config/ft32/ft32.c	(working copy)
@@ -35,6 +35,7 @@
 #include "calls.h"
 #include "expr.h"
 #include "builtins.h"
+#include "print-tree.h"
 
 /* This file should be included last.  */
 #include "target-def.h"
@@ -895,6 +896,46 @@ yes:
   return 1;
 }
 
+#undef TARGET_ENCODE_SECTION_INFO
+#define TARGET_ENCODE_SECTION_INFO  ft32_elf_encode_section_info
+
+void
+ft32_elf_encode_section_info (tree decl, rtx rtl, int first)
+{
+  enum tree_code code;
+  rtx symbol;
+
+  /* Careful not to prod global register variables.  */
+  if (!MEM_P (rtl))
+    return;
+  symbol = XEXP (rtl, 0);
+  if (GET_CODE (symbol) != SYMBOL_REF)
+    return;
+
+  default_encode_section_info (decl, rtl, first);
+
+  code = TREE_CODE (decl);
+  switch (TREE_CODE_CLASS (code))
+    {
+    case tcc_declaration:
+      {
+	tree type = TREE_TYPE (decl);
+	int is_flash = (type && TYPE_P (type) && !ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (type)));
+	if ((code == VAR_DECL) && !is_flash)
+	  SYMBOL_REF_FLAGS (symbol) |= 0x1000;
+      }
+      break;
+    case tcc_constant:
+    case tcc_exceptional:
+      if (code == STRING_CST)
+	SYMBOL_REF_FLAGS (symbol) |= 0x1000;
+    }
+
+  // debug_tree (decl);
+  // debug_rtx (rtl);
+  // printf("\n");
+}
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-ft32.h"
Index: gcc/config/ft32/ft32.h
===================================================================
--- gcc/config/ft32/ft32.h	(revision 237998)
+++ gcc/config/ft32/ft32.h	(working copy)
@@ -506,4 +506,14 @@ do { \
 
 extern int ft32_is_mem_pm(rtx o);
 
+#define ASM_OUTPUT_SYMBOL_REF(stream, sym) \
+  do { \
+    assemble_name (stream, XSTR (sym, 0)); \
+    int section_debug = in_section && \
+      (SECTION_STYLE (in_section) == SECTION_NAMED) && \
+      (in_section->named.common.flags & SECTION_DEBUG); \
+    if (!section_debug && SYMBOL_REF_FLAGS (sym) & 0x1000) \
+      asm_fprintf (stream, "-0x800000"); \
+  } while (0)
+
 #endif /* GCC_FT32_H */


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