海湾合作委员会链接器意外地向后移动位置计数器

发布于 2025-01-31 15:59:39 字数 1374 浏览 1 评论 0原文

我正在开发新的rtems bsp，并且正在修改链接脚本，我

    .rwbarrier : ALIGN_WITH_INPUT {
        . = ALIGN (bsp_section_rwbarrier_align);
    } > REGION_DATA AT > REGION_DATA

    .vector : ALIGN_WITH_INPUT {
        bsp_section_vector_begin = .;
        . = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;
        bsp_section_vector_end = .;
    } > REGION_VECTOR AT > REGION_VECTOR

让我们假设我们需要将.vector部分放在某个内存区域的中间线：

    .vector : ALIGN_WITH_INPUT {
        . = ALIGN(128);
        bsp_section_vector_begin = .;

现在我得到了此错误：

[build] linkcmds.base:xxx cannot move location counter backwards (from 0000000060022380 to 0000000060022370)

它直接指向此行，

. = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;

但是当将此行更改为：

. = . + bsp_vector_table_size;

没有错误时，链接器满足，系统异常正在工作。

我的问题是：这样的表达如何：

. = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;

以这样的方式进行评估，它试图将位置计数器向后移动？我确定bsp_vector_table_size是正数，我的实验证实了这一点。 。 =。 + 0也有效。这种兴趣是什么问题？

原文

I am developing new RTEMS BSP and I am modifying linker scripts

I modified this linker script file

    .rwbarrier : ALIGN_WITH_INPUT {
        . = ALIGN (bsp_section_rwbarrier_align);
    } > REGION_DATA AT > REGION_DATA

    .vector : ALIGN_WITH_INPUT {
        bsp_section_vector_begin = .;
        . = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;
        bsp_section_vector_end = .;
    } > REGION_VECTOR AT > REGION_VECTOR

Lets suppose that we need to put .vector section in the middle of some memory region thus we need symbol bsp_section_vector_begin to be aligned to 128, so I added this one line:

    .vector : ALIGN_WITH_INPUT {
        . = ALIGN(128);
        bsp_section_vector_begin = .;

Now I get this error:

[build] linkcmds.base:xxx cannot move location counter backwards (from 0000000060022380 to 0000000060022370)

Which is pointing directly to this line

. = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;

But when changed this line to:

. = . + bsp_vector_table_size;

There is no error, linker is satisfied and system exceptions are working.

My question is: how can such an expression like this:

. = . + DEFINED (bsp_vector_table_in_start_section) ? 0 : bsp_vector_table_size;

evaluate in a such way it try to move location counter backward? I am sure bsp_vector_table_size is positive number, and my experiment confirmed it. . = . + 0 works as well. What is wrong with this espression?

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