[ELF] Refine LMA offset propagation rule in D76995
If neither AT(lma) nor AT>lma_region is specified,
D76995 keeps `lmaOffset` (LMA - VMA) if the previous section is in the
default LMA region.
This patch additionally checks that the two sections are in the same
memory region.
Add a test case derived from https://bugs.llvm.org/show_bug.cgi?id=45313
.mdata : AT(0xfb01000) { *(.data); } > TCM
// It is odd to make .bss inherit lmaOffset, because the two sections
// are in different memory regions.
.bss : { *(.bss) } > DDR
With this patch, section VMA/LMA match GNU ld. Note, GNU ld supports
out-of-order (w.r.t sh_offset) sections and places .text and .bss in the
same PT_LOAD. We don't have that behavior.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D81986
diff --git a/lld/docs/ELF/linker_script.rst b/lld/docs/ELF/linker_script.rst
index c5115c1..0f409b2 100644
--- a/lld/docs/ELF/linker_script.rst
+++ b/lld/docs/ELF/linker_script.rst
@@ -71,7 +71,7 @@
If neither ``AT(lma)`` nor ``AT>lma_region`` is specified:
-- If the previous section is also in the default LMA region, the difference
- between the LMA and the VMA is computed to be the same as the previous
- difference.
+- If the previous section is also in the default LMA region, and the two
+ section have the same memory regions, the difference between the LMA and the
+ VMA is computed to be the same as the previous difference.
- Otherwise, the LMA is set to the VMA.
