Fix line table regression

Simon pointed out a line table regression, and after a couple of false
starts, I was able to reproduce it by hand using his instructions.

The bug is that most of the code in do_mixed_source_and_assembly uses
unrelocated addresses, but one spot does:

  pc = low;

... after the text offset has been removed.

This patch fixes the problem by introducing a new type to represent
unrelocated addresses in the line table.  This prevents this sort of
bug to some degree (it's still possible to manipulate a CORE_ADDR in a
bad way, this is unavoidable).

However, this did let the compiler flag a few spots in that function,
and now it's not possible to compare an unrelocated address from a
line table with an ordinary CORE_ADDR.

Regression tested on x86-64 Fedora 36, though note this setup never
reproduced the bug in the first place.  I also tested it by hand on
the disasm-optim test program.

1 files changed, 15 insertions, 9 deletions

diff --git a/gdb/disasm.c b/gdb/disasm.c
index 71d3b97..03cd4b7 100644
--- a/gdb/disasm.c
+++ b/gdb/disasm.c
@@ -594,8 +594,11 @@ do_mixed_source_and_assembly_deprecated
     alloca (nlines * sizeof (struct deprecated_dis_line_entry));
 
   struct objfile *objfile = symtab->compunit ()->objfile ();
-  low -= objfile->text_section_offset ();
-  high -= objfile->text_section_offset ();
+
+  unrelocated_addr unrel_low
+    = unrelocated_addr (low - objfile->text_section_offset ());
+  unrelocated_addr unrel_high
+    = unrelocated_addr (high - objfile->text_section_offset ());
 
   /* Copy linetable entries for this function into our data
      structure, creating end_pc's and setting out_of_order as
@@ -603,11 +606,11 @@ do_mixed_source_and_assembly_deprecated
 
   /* First, skip all the preceding functions.  */
 
-  for (i = 0; i < nlines - 1 && le[i].raw_pc () < low; i++);
+  for (i = 0; i < nlines - 1 && le[i].raw_pc () < unrel_low; i++);
 
   /* Now, copy all entries before the end of this function.  */
 
-  for (; i < nlines - 1 && le[i].raw_pc () < high; i++)
+  for (; i < nlines - 1 && le[i].raw_pc () < unrel_high; i++)
     {
       if (le[i] == le[i + 1])
 	continue;		/* Ignore duplicates.  */
@@ -627,7 +630,7 @@ do_mixed_source_and_assembly_deprecated
   /* If we're on the last line, and it's part of the function,
      then we need to get the end pc in a special way.  */
 
-  if (i == nlines - 1 && le[i].raw_pc () < high)
+  if (i == nlines - 1 && le[i].raw_pc () < unrel_high)
     {
       mle[newlines].line = le[i].line;
       mle[newlines].start_pc = le[i].pc (objfile);
@@ -739,8 +742,11 @@ do_mixed_source_and_assembly (struct gdbarch *gdbarch,
   htab_up dis_line_table (allocate_dis_line_table ());
 
   struct objfile *objfile = main_symtab->compunit ()->objfile ();
-  low -= objfile->text_section_offset ();
-  high -= objfile->text_section_offset ();
+
+  unrelocated_addr unrel_low
+    = unrelocated_addr (low - objfile->text_section_offset ());
+  unrelocated_addr unrel_high
+    = unrelocated_addr (high - objfile->text_section_offset ());
 
   pc = low;
 
@@ -755,10 +761,10 @@ do_mixed_source_and_assembly (struct gdbarch *gdbarch,
   first_le = NULL;
 
   /* Skip all the preceding functions.  */
-  for (i = 0; i < nlines && le[i].raw_pc () < low; i++)
+  for (i = 0; i < nlines && le[i].raw_pc () < unrel_low; i++)
     continue;
 
-  if (i < nlines && le[i].raw_pc () < high)
+  if (i < nlines && le[i].raw_pc () < unrel_high)
     first_le = &le[i];
 
   /* Add lines for every pc value.  */