[binutils-gdb] PR gas/20312: Do not pad sections to alignment on failed assembly

[Maciej W.Rozycki <macro at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=93a24ba79b59ec343611c16cd0024a116a705274

commit 93a24ba79b59ec343611c16cd0024a116a705274
Author: Maciej W. Rozycki <macro@imgtec.com>
Date:   Wed Jun 29 01:38:50 2016 +0100

    PR gas/20312: Do not pad sections to alignment on failed assembly
    
    Correct a regression from commit 85024cd8bcb9 ("Run write_object_file
    after errors") causing unsuccessful assembly, which may be due to any
    reason, such as supplying a valid source like this:
    
    	.text
    	.byte	0
    	.err
    
    to terminate with an assertion failure like:
    
    test.s: Assembler messages:
    test.s:3: Error: .err encountered
    ../as-new: BFD (GNU Binutils) 2.24.51.20140628 internal error, aborting at .../gas/write.c line 608 in size_seg
    ../as-new: Please report this bug.
    
    on targets whose default text section alignment is above 0, typically
    RISC machines.
    
    This is due to an attempt to set last text section's frag alignment to
    0, requested from `subsegs_finish_section' where `frag_align_code
    (alignment, 0)' is called with `alignment' set to 0 rather than the
    section alignment if `had_errors' has returned true.  The call to
    `subsegs_finish_section' is made from `subsegs_finish' from
    `write_object_file' at unsuccessful completion, which previously wasn't
    made.
    
    Always set last section's frag alignment from the section alignment
    then, forcing no section padding instead if completing unsuccessfully,
    so that in that case alignment padding is still suppressed from any
    listing generated, fixing assertion failures for these targets:
    
    alpha-linuxecoff  -FAIL: all pr20312
    arm-aout  -FAIL: all pr20312
    mips-freebsd  -FAIL: all pr20312
    mips-img-linux  -FAIL: all pr20312
    mips-linux  -FAIL: all pr20312
    mips-mti-linux  -FAIL: all pr20312
    mips-netbsd  -FAIL: all pr20312
    mips-sgi-irix5  -FAIL: all pr20312
    mips-sgi-irix6  -FAIL: all pr20312
    mips-vxworks  -FAIL: all pr20312
    mips64-freebsd  -FAIL: all pr20312
    mips64-img-linux  -FAIL: all pr20312
    mips64-linux  -FAIL: all pr20312
    mips64-mti-linux  -FAIL: all pr20312
    mips64-openbsd  -FAIL: all pr20312
    mips64el-freebsd  -FAIL: all pr20312
    mips64el-img-linux  -FAIL: all pr20312
    mips64el-linux  -FAIL: all pr20312
    mips64el-mti-linux  -FAIL: all pr20312
    mips64el-openbsd  -FAIL: all pr20312
    mipsel-freebsd  -FAIL: all pr20312
    mipsel-img-linux  -FAIL: all pr20312
    mipsel-linux  -FAIL: all pr20312
    mipsel-mti-linux  -FAIL: all pr20312
    mipsel-netbsd  -FAIL: all pr20312
    mipsel-vxworks  -FAIL: all pr20312
    mipsisa32-linux  -FAIL: all pr20312
    mipsisa32el-linux  -FAIL: all pr20312
    mipsisa64-linux  -FAIL: all pr20312
    mipsisa64el-linux  -FAIL: all pr20312
    sh-pe  -FAIL: all pr20312
    sparc-aout  -FAIL: all pr20312
    
    	gas/
    	PR gas/20312
    	* write.c (subsegs_finish_section): Force no section padding to
    	alignment on failed assembly, always set last frag's alignment
    	from section.
    	* testsuite/gas/all/pr20312.l: New list test.
    	* testsuite/gas/all/pr20312.s: New test source.
    	* testsuite/gas/all/gas.exp: Run the new test

Diff:
---
 gas/ChangeLog                   | 10 ++++++++++
 gas/testsuite/gas/all/gas.exp   |  2 ++
 gas/testsuite/gas/all/pr20312.l |  2 ++
 gas/testsuite/gas/all/pr20312.s |  3 +++
 gas/write.c                     | 32 ++++++++++++++++----------------
 5 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 04a84fa..300d5ca 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2016-06-30  Maciej W. Rozycki  <macro@imgtec.com>
+
+	PR gas/20312
+	* write.c (subsegs_finish_section): Force no section padding to
+	alignment on failed assembly, always set last frag's alignment
+	from section.
+	* testsuite/gas/all/pr20312.l: New list test.
+	* testsuite/gas/all/pr20312.s: New test source.
+	* testsuite/gas/all/gas.exp: Run the new test
+
 2016-06-30  Matthew Wahab  <matthew.wahab@arm.com>
 
 	* testsuite/gas/arm/armv8_2+rdma.d: New.
diff --git a/gas/testsuite/gas/all/gas.exp b/gas/testsuite/gas/all/gas.exp
index d5d2445..bfb13ed 100644
--- a/gas/testsuite/gas/all/gas.exp
+++ b/gas/testsuite/gas/all/gas.exp
@@ -448,6 +448,8 @@ if [is_elf_format] {
 
 run_dump_test quoted-sym-names
 
+run_list_test pr20312
+
 load_lib gas-dg.exp
 dg-init
 dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/err-*.s $srcdir/$subdir/warn-*.s]] "" ""
diff --git a/gas/testsuite/gas/all/pr20312.l b/gas/testsuite/gas/all/pr20312.l
new file mode 100644
index 0000000..47328e7
--- /dev/null
+++ b/gas/testsuite/gas/all/pr20312.l
@@ -0,0 +1,2 @@
+.*: Assembler messages:
+.*:3: Error: \.err encountered
diff --git a/gas/testsuite/gas/all/pr20312.s b/gas/testsuite/gas/all/pr20312.s
new file mode 100644
index 0000000..d88c6ba
--- /dev/null
+++ b/gas/testsuite/gas/all/pr20312.s
@@ -0,0 +1,3 @@
+	.text
+	.byte	0
+	.err
diff --git a/gas/write.c b/gas/write.c
index 8873e55..c502b08 100644
--- a/gas/write.c
+++ b/gas/write.c
@@ -1732,31 +1732,31 @@ subsegs_finish_section (asection *s)
        frchainP != NULL;
        frchainP = frchainP->frch_next)
     {
-      int alignment = 0;
+      int alignment;
 
       subseg_set (s, frchainP->frch_subseg);
 
       /* This now gets called even if we had errors.  In that case,
 	 any alignment is meaningless, and, moreover, will look weird
 	 if we are generating a listing.  */
-      if (!had_errors ())
-	{
-	  alignment = SUB_SEGMENT_ALIGN (now_seg, frchainP);
-	  if ((bfd_get_section_flags (now_seg->owner, now_seg) & SEC_MERGE)
-	      && now_seg->entsize)
-	    {
-	      unsigned int entsize = now_seg->entsize;
-	      int entalign = 0;
+      if (had_errors ())
+	do_not_pad_sections_to_alignment = 1;
 
-	      while ((entsize & 1) == 0)
-		{
-		  ++entalign;
-		  entsize >>= 1;
-		}
+      alignment = SUB_SEGMENT_ALIGN (now_seg, frchainP);
+      if ((bfd_get_section_flags (now_seg->owner, now_seg) & SEC_MERGE)
+	  && now_seg->entsize)
+	{
+	  unsigned int entsize = now_seg->entsize;
+	  int entalign = 0;
 
-	      if (entalign > alignment)
-		alignment = entalign;
+	  while ((entsize & 1) == 0)
+	    {
+	      ++entalign;
+	      entsize >>= 1;
 	    }
+
+	  if (entalign > alignment)
+	    alignment = entalign;
 	}
 
       if (subseg_text_p (now_seg))