From 68a91eb7ac94f0e0c6e9ebd7ad148c80cbc227df Mon Sep 17 00:00:00 2001
From: Nagaraju Mekala <nmekala@xilix.com>
Date: Mon, 6 Feb 2017 15:53:08 +0530
Subject: [PATCH] Fixup debug_loc sections after linker relaxation Adds a new
 reloctype R_MICROBLAZE_32_NONE, used for passing reloc info from the
 assembler to the linker when the linker manages to fully resolve a local
 symbol reference.

This is a workaround for design flaws in the assembler to
linker interface with regards to linker relaxation.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Nagaraju Mekala <nagaraju.mekala@xilinx.com>

---
 bfd/bfd-in2.h              |  9 ++++++--
 bfd/elf32-microblaze.c     | 53 ++++++++++++++++++++++++++++++++++------------
 bfd/libbfd.h               |  1 +
 bfd/reloc.c                |  6 ++++++
 binutils/readelf.c         |  4 ++++
 gas/config/tc-microblaze.c |  5 ++++-
 include/elf/microblaze.h   |  2 ++
 7 files changed, 64 insertions(+), 16 deletions(-)

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index e251d7e..fe6933a 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -5867,10 +5867,15 @@ value relative to the read-write small data area anchor  */
 expressions of the form "Symbol Op Symbol"  */
   BFD_RELOC_MICROBLAZE_32_SYM_OP_SYM,
 
-/* This is a 64 bit reloc that stores the 32 bit pc relative
+/* This is a 32 bit reloc that stores the 32 bit pc relative
 value in two words (with an imm instruction).  No relocation is
 done here - only used for relaxing  */
-  BFD_RELOC_MICROBLAZE_64_NONE,
+  BFD_RELOC_MICROBLAZE_32_NONE,
+
+/* This is a 64 bit reloc that stores the 32 bit pc relative
+ *  +value in two words (with an imm instruction).  No relocation is
+ *   +done here - only used for relaxing  */
+    BFD_RELOC_MICROBLAZE_64_NONE,
 
 /* This is a 64 bit reloc that stores the 32 bit pc relative
 value in two words (with an imm instruction).  The relocation is
diff --git a/bfd/elf32-microblaze.c b/bfd/elf32-microblaze.c
index 359484d..1c69c26 100644
--- a/bfd/elf32-microblaze.c
+++ b/bfd/elf32-microblaze.c
@@ -176,7 +176,21 @@ static reloc_howto_type microblaze_elf_howto_raw[] =
 	  0x0000ffff,		/* Dest Mask.  */
 	  FALSE),		/* PC relative offset?  */
 
-   /* This reloc does nothing.	Used for relaxation.  */
+   HOWTO (R_MICROBLAZE_32_NONE,   /* Type.  */
+          0,         /* Rightshift.  */
+          2,            /* Size (0 = byte, 1 = short, 2 = long).  */
+          32,           /* Bitsize.  */
+          TRUE,         /* PC_relative.  */
+          0,           /* Bitpos.  */
+          complain_overflow_bitfield,  /* Complain on overflow.  */
+          NULL,                  /* Special Function.  */
+          "R_MICROBLAZE_32_NONE",/* Name.  */
+          FALSE,       /* Partial Inplace.  */
+          0,          /* Source Mask.  */
+          0,         /* Dest Mask.  */
+          FALSE),       /* PC relative offset?  */
+
+   /* This reloc does nothing.  Used for relaxation.  */
    HOWTO (R_MICROBLAZE_64_NONE,	/* Type.  */
 	  0,			/* Rightshift.  */
 	  3,			/* Size (0 = byte, 1 = short, 2 = long).  */
@@ -562,6 +576,9 @@ microblaze_elf_reloc_type_lookup (bfd * abfd ATTRIBUTE_UNUSED,
     case BFD_RELOC_NONE:
       microblaze_reloc = R_MICROBLAZE_NONE;
       break;
+    case BFD_RELOC_MICROBLAZE_32_NONE:
+      microblaze_reloc = R_MICROBLAZE_32_NONE;
+      break;
     case BFD_RELOC_MICROBLAZE_64_NONE:
       microblaze_reloc = R_MICROBLAZE_64_NONE;
       break;
@@ -1918,6 +1935,7 @@ microblaze_elf_relax_section (bfd *abfd,
 		}
 	      break;
 	    case R_MICROBLAZE_NONE:
+	    case R_MICROBLAZE_32_NONE:
 	      {
 		/* This was a PC-relative instruction that was
 		   completely resolved.  */
@@ -1926,12 +1944,18 @@ microblaze_elf_relax_section (bfd *abfd,
 		target_address = irel->r_addend + irel->r_offset;
 		sfix = calc_fixup (irel->r_offset, 0, sec);
 		efix = calc_fixup (target_address, 0, sec);
+
+		/* Validate the in-band val.  */
+		val = bfd_get_32 (abfd, contents + irel->r_offset);
+		if (val != irel->r_addend && ELF32_R_TYPE (irel->r_info) == R_MICROBLAZE_32_NONE) {
+		       fprintf(stderr, "%d: CORRUPT relax reloc %x %lx\n", __LINE__, val, irel->r_addend);
+		}
 		irel->r_addend -= (efix - sfix);
 		/* Should use HOWTO.  */
 		microblaze_bfd_write_imm_value_32 (abfd, contents + irel->r_offset,
 						   irel->r_addend);
-	      }
-	      break;
+		}
+		break;
 	    case R_MICROBLAZE_64_NONE:
 	      {
 		/* This was a PC-relative 64-bit instruction that was
@@ -1973,12 +1997,16 @@ microblaze_elf_relax_section (bfd *abfd,
 	  irelscanend = irelocs + o->reloc_count;
 	  for (irelscan = irelocs; irelscan < irelscanend; irelscan++)
 	    {
-              if (ELF32_R_TYPE (irelscan->r_info) == (int) R_MICROBLAZE_NONE)
+             if (1 && ELF32_R_TYPE (irelscan->r_info) == (int) R_MICROBLAZE_32_NONE)
                 {
                   unsigned int val;
 
                   isym = isymbuf + ELF32_R_SYM (irelscan->r_info);
 
+                  /* hax: We only do the following fixup for debug location lists.  */
+                  if (strcmp(".debug_loc", o->name))
+                    continue;
+
                   /* This was a PC-relative instruction that was completely resolved.  */
                   if (ocontents == NULL)
                     {
@@ -1999,18 +2027,17 @@ microblaze_elf_relax_section (bfd *abfd,
                                                          (file_ptr) 0,
                                                          o->rawsize))
                               goto error_return;
-                          elf_section_data (o)->this_hdr.contents = ocontents;
-                        }
-                    }
-                 irelscan->r_addend -= calc_fixup (irelscan->r_addend
-                                                    + isym->st_value, sec);
+		          elf_section_data (o)->this_hdr.contents = ocontents;
+		        }
+		    }
                   val = bfd_get_32 (abfd, ocontents + irelscan->r_offset);
+                  if (val != irelscan->r_addend) {
+                    fprintf(stderr, "%d: CORRUPT relax reloc! %x %lx\n", __LINE__, val, irelscan->r_addend);
+                  }
+                  irelscan->r_addend -= calc_fixup (irelscan->r_addend, 0, sec);
                   microblaze_bfd_write_imm_value_32 (abfd, ocontents + irelscan->r_offset,
                                                      irelscan->r_addend);
               }
-              if (ELF32_R_TYPE (irelscan->r_info) == (int) R_MICROBLAZE_64_NONE) {
-                  fprintf(stderr, "Unhandled NONE 64\n");
-              }
 	      if (ELF32_R_TYPE (irelscan->r_info) == (int) R_MICROBLAZE_32)
 		{
 		  isym = isymbuf + ELF32_R_SYM (irelscan->r_info);
@@ -2070,7 +2097,7 @@ microblaze_elf_relax_section (bfd *abfd,
 			      elf_section_data (o)->this_hdr.contents = ocontents;
 			    }
 			}
-		      irelscan->r_addend -= calc_fixup (irel->r_addend
+              irelscan->r_addend -= calc_fixup (irelscan->r_addend
 							+ isym->st_value,
 							0,
 							sec);
diff --git a/bfd/libbfd.h b/bfd/libbfd.h
index 36284d7..feb9fad 100644
--- a/bfd/libbfd.h
+++ b/bfd/libbfd.h
@@ -2901,6 +2901,7 @@ static const char *const bfd_reloc_code_real_names[] = { "@@uninitialized@@",
   "BFD_RELOC_MICROBLAZE_32_ROSDA",
   "BFD_RELOC_MICROBLAZE_32_RWSDA",
   "BFD_RELOC_MICROBLAZE_32_SYM_OP_SYM",
+  "BFD_RELOC_MICROBLAZE_32_NONE",
   "BFD_RELOC_MICROBLAZE_64_NONE",
   "BFD_RELOC_MICROBLAZE_64_GOTPC",
   "BFD_RELOC_MICROBLAZE_64_GOT",
diff --git a/bfd/reloc.c b/bfd/reloc.c
index e6446a7..87753ae 100644
--- a/bfd/reloc.c
+++ b/bfd/reloc.c
@@ -6796,6 +6796,12 @@ ENUMDOC
   This is a 32 bit reloc for the microblaze to handle
   expressions of the form "Symbol Op Symbol"
 ENUM
+  BFD_RELOC_MICROBLAZE_32_NONE
+ENUMDOC
+  This is a 32 bit reloc that stores the 32 bit pc relative
+  value in two words (with an imm instruction).  No relocation is
+  done here - only used for relaxing
+ENUM
   BFD_RELOC_MICROBLAZE_64_NONE
 ENUMDOC
   This is a 64 bit reloc that stores the 32 bit pc relative
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 9df3742..1bbc2d1 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -13020,6 +13020,10 @@ is_none_reloc (Filedata * filedata, unsigned int reloc_type)
 	      || reloc_type == 32 /* R_AVR_DIFF32.  */);
     case EM_METAG:
       return reloc_type == 3; /* R_METAG_NONE.  */
+    case EM_MICROBLAZE:
+      return reloc_type == 30 /* R_MICROBLAZE_32_NONE.  */
+             || reloc_type == 0 /* R_MICROBLAZE_NONE.  */
+             || reloc_type == 9; /* R_MICROBLAZE_64_NONE.  */
     case EM_NDS32:
       return (reloc_type == 0       /* R_XTENSA_NONE.  */
 	      || reloc_type == 204  /* R_NDS32_DIFF8.  */
diff --git a/gas/config/tc-microblaze.c b/gas/config/tc-microblaze.c
index 3e72840..fa665b4 100644
--- a/gas/config/tc-microblaze.c
+++ b/gas/config/tc-microblaze.c
@@ -2201,7 +2201,9 @@ md_apply_fix (fixS *   fixP,
       /* This fixup has been resolved.  Create a reloc in case the linker
 	 moves code around due to relaxing.  */
       if (fixP->fx_r_type == BFD_RELOC_64_PCREL)
-	fixP->fx_r_type = BFD_RELOC_MICROBLAZE_64_NONE;
+	    fixP->fx_r_type = BFD_RELOC_MICROBLAZE_64_NONE;
+      else if (fixP->fx_r_type == BFD_RELOC_32)
+        fixP->fx_r_type = BFD_RELOC_MICROBLAZE_32_NONE;
       else
 	fixP->fx_r_type = BFD_RELOC_NONE;
       fixP->fx_addsy = section_symbol (absolute_section);
@@ -2426,6 +2428,7 @@ tc_gen_reloc (asection * section ATTRIBUTE_UNUSED, fixS * fixp)
   switch (fixp->fx_r_type)
     {
     case BFD_RELOC_NONE:
+    case BFD_RELOC_MICROBLAZE_32_NONE: 
     case BFD_RELOC_MICROBLAZE_64_NONE:
     case BFD_RELOC_32:
     case BFD_RELOC_MICROBLAZE_32_LO:
diff --git a/include/elf/microblaze.h b/include/elf/microblaze.h
index 830b5ad..6ee0966 100644
--- a/include/elf/microblaze.h
+++ b/include/elf/microblaze.h
@@ -61,6 +61,8 @@ START_RELOC_NUMBERS (elf_microblaze_reloc_type)
   RELOC_NUMBER (R_MICROBLAZE_TEXTPCREL_64, 30)  /* PC-relative TEXT offset.  */
   RELOC_NUMBER (R_MICROBLAZE_TEXTREL_64, 31)    /* TEXT Entry offset 64-bit.  */
   RELOC_NUMBER (R_MICROBLAZE_TEXTREL_32_LO, 32) /* TEXT Entry offset 32-bit.  */
+  RELOC_NUMBER (R_MICROBLAZE_32_NONE, 33)
+   
 END_RELOC_NUMBERS (R_MICROBLAZE_max)
 
 /* Global base address names.  */