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Fix line table regression

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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.
This commit is contained in:
Tom Tromey
2023-03-16 14:41:31 -06:00
parent 152d9c48a2
commit 48e0f38c30
15 changed files with 78 additions and 50 deletions
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24
gdb/disasm.c
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@@ -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. */