binutils-gdb/ld/testsuite/ld-elf/orphan-9.s

        .text
        .byte 0, 0, 0, 0, 0, 0, 0, 0

        .data
        .byte 0, 0, 0, 0, 0, 0, 0, 0

        .section ".data.1", "aw"
        .byte 0, 0, 0, 0, 0, 0, 0, 0

        .section ".rodata", "a"
        .byte 0, 0, 0, 0, 0, 0, 0, 0
ld: better handling of lma region for orphan sections When picking an lma_region for an orphan section we currently create a new lang_output_section_statement_type and then populate this with the orphan section. The problem is that the lang_output_section_statement_type has a prev pointer that links back to the previous output section. For non-orphan output sections, that are created in linker script order, the prev pointer will point to the output section that appears previous in linker script order, as you'd probably expect. The problem is that orphan sections are placed after processing the linker script, and so, in the case of an output section created for an orphan input section, the prev pointer actually points to the last output section created. This causes some unexpected behaviour when the orphan section is not placed after the last non-orphan section that was created. For example, consider this linker script: MEMORY { TEXT : ORIGIN = 0x200, LENGTH = 0x10 RODATA : ORIGIN = 0x400, LENGTH = 0x10 } SECTIONS { .text : {(.text) } AT>TEXT .data : AT(0x300) { (.data) } .rodata : { (.rodata) } AT>RODATA } If we are processing an orphan section '.data.1' and decide to place this after '.data', then the output section created will have a prev pointer that references the '.rodata' output section. The result of this is that '.data.1' will actually be assigned to the RODATA lma region, which is probably not the expected behaviour. The reason why '.data.1' is placed into the lma region of the '.rodata' section is that lma region propagation is done at the time we create the output section, based on the previous output section pointer, which is really just a last-output-section-created pointer at that point in time, though the prev point is fixed up later to reflect the true order of the output sections. The solution I propose in this commit is to move the propagation of lma regions into a separate pass of the linker, rather than performing this as part of the enter/exit of output sections during linker script parsing. During this later phase we have all of the output sections to hand, and the prev/next points have been fixed up by this point to reflect the actual placement ordering. There's a new test to cover this issue that passes on a range of targets, however, some targets generate additional sections, or have stricter memory region size requirements that make it harder to come up with a generic pass pattern, that still tests the required features. For now I've set the test to ignore these targets. ld/ChangeLog: ldlang.c (lang_leave_output_section_statement): Move lma_region logic to... (lang_propagate_lma_regions): ...this new function. (lang_process): Call new function. * testsuite/ld-elf/orphan-9.d: New file. * testsuite/ld-elf/orphan-9.ld: New file. * testsuite/ld-elf/orphan-9.s: New file. * NEWS: Mention change in behaviour. 2017-01-18 03:12:54 +08:00			`.text`
			`.byte 0, 0, 0, 0, 0, 0, 0, 0`

			`.data`
			`.byte 0, 0, 0, 0, 0, 0, 0, 0`

			`.section ".data.1", "aw"`
			`.byte 0, 0, 0, 0, 0, 0, 0, 0`

			`.section ".rodata", "a"`
			`.byte 0, 0, 0, 0, 0, 0, 0, 0`