[binutils-gdb] IBM Z: Fix pcrel relocs for symA-symB expressions

[binutils-gdb] IBM Z: Fix pcrel relocs for symA-symB expressions

[Andreas Krebbel]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=d32e20f0bf7dcafd712e532e1274f64f613088e6

commit d32e20f0bf7dcafd712e532e1274f64f613088e6
Author: Andreas Krebbel <krebbel@linux.ibm.com>
Date:   Mon Jul 3 19:51:51 2023 +0200

    IBM Z: Fix pcrel relocs for symA-symB expressions
    
    The code in md_apply_fix which tries to deduce from the operand type
    which reloc to apply currently does the wrong thing for absolute
    relocs which have been re-written by fixup_segment as pc-relative to
    implement a subtraction of a local and an external symbol.
    
    In all these cases we wrongly emit an absolute reloc because we ignore
    the fx_pcrel flag in md_apply_fix. However, only for the last one we
    actually support a pc relative relocation of the proper size and can
    implement it accordingly. For the other 3 we have to issue an error.
    
    foo:
      cli   0(%r2),undef-foo
      la    %r2,undef-foo(%r2)
      lay   %r2,undef-foo(%r2)
      lhi   %r2,undef-foo

Diff:
---
 gas/config/tc-s390.c               | 14 ++++++++++----
 gas/testsuite/gas/s390/esa-reloc.d |  2 +-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/gas/config/tc-s390.c b/gas/config/tc-s390.c
index 955851946f9..765a9a2e6bd 100644
--- a/gas/config/tc-s390.c
+++ b/gas/config/tc-s390.c
@@ -2291,25 +2291,25 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
 	 We are only prepared to turn a few of the operands into
 	 relocs.  */
       fixP->fx_offset = value;
-      if (operand->bits == 12 && operand->shift == 20)
+      if (operand->bits == 12 && operand->shift == 20 && !fixP->fx_pcrel)
 	{
 	  fixP->fx_size = 2;
 	  fixP->fx_where += 2;
 	  fixP->fx_r_type = BFD_RELOC_390_12;
 	}
-      else if (operand->bits == 12 && operand->shift == 36)
+      else if (operand->bits == 12 && operand->shift == 36 && !fixP->fx_pcrel)
 	{
 	  fixP->fx_size = 2;
 	  fixP->fx_where += 4;
 	  fixP->fx_r_type = BFD_RELOC_390_12;
 	}
-      else if (operand->bits == 20 && operand->shift == 20)
+      else if (operand->bits == 20 && operand->shift == 20 && !fixP->fx_pcrel)
 	{
 	  fixP->fx_size = 4;
 	  fixP->fx_where += 2;
 	  fixP->fx_r_type = BFD_RELOC_390_20;
 	}
-      else if (operand->bits == 8 && operand->shift == 8)
+      else if (operand->bits == 8 && operand->shift == 8 && !fixP->fx_pcrel)
 	{
 	  fixP->fx_size = 1;
 	  fixP->fx_where += 1;
@@ -2334,6 +2334,12 @@ md_apply_fix (fixS *fixP, valueT *valP, segT seg ATTRIBUTE_UNUSED)
 	      fixP->fx_offset += 2;
 	      fixP->fx_pcrel_adjust = 2;
 	    }
+	  else if (fixP->fx_pcrel)
+	    {
+	      fixP->fx_r_type = BFD_RELOC_16_PCREL;
+	      fixP->fx_offset += 2;
+	      fixP->fx_pcrel_adjust = 2;
+	    }
 	  else
 	    fixP->fx_r_type = BFD_RELOC_16;
 	}
diff --git a/gas/testsuite/gas/s390/esa-reloc.d b/gas/testsuite/gas/s390/esa-reloc.d
index c9da92870d5..0b13cb626a6 100644
--- a/gas/testsuite/gas/s390/esa-reloc.d
+++ b/gas/testsuite/gas/s390/esa-reloc.d
@@ -23,7 +23,7 @@ Disassembly of section .text:
   22:	a7 08 00 00 [ 	]*lhi	%r0,0
 [ 	]*24: R_390_GOT16	test_R_390_GOT16
   26:	a7 08 00 00 [ 	]*lhi	%r0,0
-[ 	]*28: R_390_16	test_R_390_PC16\+0x26
+[ 	]*28: R_390_PC16	test_R_390_PC16\+0x28
   2a:	a7 e5 00 00 [ 	]*bras	%r14,2a <foo\+0x2a>
 [ 	]*2c: R_390_PC16DBL	test_R_390_PC16DBL\+0x2
   2e:	a7 e5 00 00 [ 	]*bras	%r14,2e <foo\+0x2e>