* NEWS: Mention LMA default change.
* ld.texinfo (Output Section LMA): Update default description. (Location Counter): Clarify backward movement. * ldlang.c (lang_size_sections_1): Leave non-alloc sections with default lma equal to vma. Warn on backward movement of dot.
This commit is contained in:
Alan Modra
parent
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4 changed files with 53 additions and 11 deletions
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@ -1,3 +1,11 @@
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2006-08-22 Alan Modra <amodra@bigpond.net.au>
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* NEWS: Mention LMA default change.
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* ld.texinfo (Output Section LMA): Update default description.
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(Location Counter): Clarify backward movement.
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* ldlang.c (lang_size_sections_1): Leave non-alloc sections with
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default lma equal to vma. Warn on backward movement of dot.
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2006-08-22 Pedro Alves <pedro_alves@portugalmail.pt>
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* Makefile.am: Split arm-wince into its own emulation.
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6
ld/NEWS
6
ld/NEWS
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@ -1,4 +1,10 @@
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-*- text -*-
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* The default output section LMA has changed for allocatable sections from
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being equal to VMA, to keeping the difference between LMA and VMA the same as
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the previous output section in the same region. This is a more useful
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default when using overlays and other cases where you specify an LMA
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differing from the VMA for some sections.
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* New switch: --print-gc-sections to list any sections removed by garabge
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collection.
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@ -3764,15 +3764,20 @@ Every section has a virtual address (VMA) and a load address (LMA); see
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an output section description sets the VMA (@pxref{Output Section
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Address}).
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The linker will normally set the LMA equal to the VMA. You can change
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that by using the @code{AT} keyword. The expression @var{lma} that
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follows the @code{AT} keyword specifies the load address of the
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section.
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The expression @var{lma} that follows the @code{AT} keyword specifies
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the load address of the section.
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Alternatively, with @samp{AT>@var{lma_region}} expression, you may
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specify a memory region for the section's load address. @xref{MEMORY}.
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Note that if the section has not had a VMA assigned to it then the
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linker will use the @var{lma_region} as the VMA region as well.
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If neither @code{AT} nor @code{AT>} is specified for an allocatable
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section, the linker will set the LMA such that the difference between
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VMA and LMA for the section is the same as the preceding output
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section in the same region. If there is no preceding output section
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or the section is not allocatable, the linker will set the LMA equal
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to the VMA.
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@xref{Output Section Region}.
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@cindex ROM initialized data
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@ -4586,7 +4591,9 @@ anywhere that an ordinary symbol is allowed in an expression.
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@cindex holes
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Assigning a value to @code{.} will cause the location counter to be
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moved. This may be used to create holes in the output section. The
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location counter may never be moved backwards.
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location counter may not be moved backwards inside an output section,
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and may not be moved backwards outside of an output section if so
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doing creates areas with overlapping LMAs.
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@smallexample
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SECTIONS
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33
ld/ldlang.c
33
ld/ldlang.c
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@ -4400,16 +4400,30 @@ lang_size_sections_1
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lma = align_power (lma, os->section_alignment);
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os->bfd_section->lma = lma;
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}
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else if (r->last_os != NULL)
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else if (r->last_os != NULL
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&& (os->bfd_section->flags & SEC_ALLOC) != 0)
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{
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bfd_vma lma;
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asection *last;
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last = r->last_os->output_section_statement.bfd_section;
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/* If dot moved backwards (which is invalid according
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to ld docs) then leave lma equal to vma. This
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keeps users of buggy ld scripts happy. */
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if (dot >= last->vma)
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/* A backwards move of dot should be accompanied by
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an explicit assignment to the section LMA (ie.
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os->load_base set) because backwards moves normally
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create overlapping LMAs. */
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if (dot < last->vma)
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{
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einfo (_("%P: warning: dot moved backwards before `%s'\n"),
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os->name);
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/* If dot moved backwards then leave lma equal to
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vma. This is the old default lma, which might
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just happen to work when the backwards move is
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sufficiently large. Nag anyway, so people fix
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their linker scripts. */
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}
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else
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{
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/* If the current vma overlaps the previous section,
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then set the current lma to that at the end of
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@ -4440,9 +4454,16 @@ lang_size_sections_1
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lma region. We use this to set the lma for
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following sections. Overlays or other linker
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script assignment to lma might mean that the
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default lma == vma is incorrect. */
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default lma == vma is incorrect.
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To avoid warnings about dot moving backwards when using
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-Ttext, don't start tracking sections until we find one
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of non-zero size or with lma set differently to vma. */
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if (((os->bfd_section->flags & SEC_HAS_CONTENTS) != 0
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|| (os->bfd_section->flags & SEC_THREAD_LOCAL) == 0)
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&& (os->bfd_section->flags & SEC_ALLOC) != 0
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&& (os->bfd_section->size != 0
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|| os->bfd_section->vma != os->bfd_section->lma
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|| r->last_os != NULL)
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&& os->lma_region == NULL
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&& !link_info.relocatable)
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r->last_os = s;
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