899fdf548e
This implements https://sourceware.org/bugzilla/show_bug.cgi?id=26404 An `OVERWRITE_SECTIONS` command is a `SECTIONS` variant which contains several output section descriptions. The output sections do not have specify an order. Similar to `INSERT [BEFORE|AFTER]`, `LinkerScript::hasSectionsCommand` is not set, so the built-in rules (see `docs/ELF/linker_script.rst`) still apply. `OVERWRITE_SECTIONS` can be more convenient than `INSERT` because it does not need an anchor section. The initial syntax is intentionally narrow to facilitate backward compatible extensions in the future. Symbol assignments cannot be used. This feature is versatile. To list a few usage: * Use `section : { KEEP(...) }` to retain input sections under GC * Define encapsulation symbols (start/end) for an output section * Use `section : ALIGN(...) : { ... }` to overalign an output section (similar to ld64 `-sectalign`) When an output section is specified by both `OVERWRITE_SECTIONS` and `INSERT`, `INSERT` is processed after overwrite sections. To make this work, this patch changes `InsertCommand` to use name based matching instead of pointer based matching. (This may cause a difference when `INSERT` moves one output section more than once. Such duplicate commands should not be used in practice (seems that in GNU ld the output sections may just disappear).) A linker script can be used without -T/--script. The traditional `SECTIONS` commands are concatenated, so a wrong rule can be more noticeable from the section order. This feature if misused can be less noticeable, just like `INSERT`. Differential Revision: https://reviews.llvm.org/D103303
137 lines
5.9 KiB
Plaintext
137 lines
5.9 KiB
Plaintext
# REQUIRES: x86
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# RUN: rm -rf %t && split-file %s %t
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# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o
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## There is no main linker script. OVERWRITE_SECTIONS defines output section
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## descriptions and follows the usual orphan placement rules.
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# RUN: ld.lld %t/overwrite1.lds %t/a.o -o %t1
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# RUN: llvm-readelf -S %t1 | FileCheck %s --check-prefix=CHECK1
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# CHECK1: Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK1-NEXT: NULL [[#%x,]] [[#%x,]] 000000
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# CHECK1-NEXT: .text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 4
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# CHECK1-NEXT: .foo.text PROGBITS [[#%x,]] [[#%x,]] 000002 00 WAX 0 0 8
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# CHECK1-NEXT: .data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK1-NEXT: .comment PROGBITS {{.*}}
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# RUN: ld.lld %t/overwrite1.lds %t/overwrite1.lds %t/a.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=WARN1
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# WARN1: warning: OVERWRITE_SECTIONS specifies duplicate .foo.text
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## The output section description order (.foo.data .foo.text) does not affect
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## the output order.
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# RUN: ld.lld %t/overwrite2.lds %t/a.o -o %t2
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# RUN: llvm-readelf -S -s %t2 | FileCheck %s --check-prefix=CHECK2
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# CHECK2: [Nr] Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK2-NEXT: [ 0] NULL [[#%x,]] [[#%x,]] 000000
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# CHECK2-NEXT: [ 1] .text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 4
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# CHECK2-NEXT: [ 2] .foo.text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 1
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# CHECK2-NEXT: [ 3] .data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK2-NEXT: [ 4] .foo.data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK2-NEXT: [ 5] .comment PROGBITS {{.*}}
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# CHECK2: Num: Value Size Type Bind Vis Ndx Name
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# CHECK2: [[#]]: [[#%x,ADDR:]] 0 NOTYPE GLOBAL DEFAULT 4 FOO_DATA_START
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# CHECK2-NEXT: [[#]]: {{0*}}[[#ADDR+1]] 0 NOTYPE GLOBAL DEFAULT 4 FOO_DATA_END
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# CHECK2-NEXT: [[#]]: [[#%x,ADDR:]] 0 NOTYPE GLOBAL DEFAULT 2 FOO_TEXT_START
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# CHECK2-NEXT: [[#]]: {{0*}}[[#ADDR+1]] 0 NOTYPE GLOBAL DEFAULT 2 FOO_TEXT_END
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## OVERWRITE_SECTIONS is processed before the main script. The main script
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## specifies the output order. The alignment of .foo.text is specified by
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## OVERWRITE_SECTIONS insteaad of the main script.
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# RUN: ld.lld -T %t/main.lds %t/overwrite1.lds %t/a.o -o %t3 2>&1 | count 0
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# RUN: llvm-readelf -S %t3 | FileCheck %s --check-prefix=CHECK3
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# RUN: ld.lld %t/overwrite1.lds -T %t/main.lds %t/a.o -o %t3 2>&1 | count 0
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# RUN: llvm-readelf -S %t3 | FileCheck %s --check-prefix=CHECK3
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# CHECK3: Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK3-NEXT: NULL [[#%x,]] [[#%x,]] 000000
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# CHECK3-NEXT: .data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK3-NEXT: .text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 4
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# CHECK3-NEXT: .foo.text PROGBITS [[#%x,]] [[#%x,]] 000002 00 WAX 0 0 8
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# CHECK3-NEXT: .comment PROGBITS {{.*}}
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# RUN: ld.lld -T %t/main.lds %t/overwrite1.lds %t/a.o -o %t3 --verbose 2>&1 | FileCheck %s --check-prefix=VERBOSE3
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# VERBOSE3: {{.*}}overwrite1.lds:[[#]] overwrites .foo.text
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## If INSERT commands are specified, INSERT commands are processed after overwrite sections.
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# RUN: ld.lld %t/insert.lds %t/overwrite2.lds %t/a.o -o %t4
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# RUN: llvm-readelf -S -s %t4 | FileCheck %s --check-prefix=CHECK4
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# CHECK4: [Nr] Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK4-NEXT: [ 0] NULL [[#%x,]] [[#%x,]] 000000
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# CHECK4-NEXT: [ 1] .text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 4
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# CHECK4-NEXT: [ 2] .data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK4-NEXT: [ 3] .foo.data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK4-NEXT: [ 4] .foo.text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 1
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# CHECK4-NEXT: [ 5] .comment PROGBITS {{.*}}
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# CHECK4: Num: Value Size Type Bind Vis Ndx Name
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# CHECK4: [[#]]: [[#%x,ADDR:]] 0 NOTYPE GLOBAL DEFAULT 4 FOO_TEXT_START
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# CHECK4-NEXT: [[#]]: {{0*}}[[#ADDR+1]] 0 NOTYPE GLOBAL DEFAULT 4 FOO_TEXT_END
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# CHECK4-NEXT: [[#]]: [[#%x,ADDR:]] 0 NOTYPE GLOBAL DEFAULT 3 FOO_DATA_START
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# CHECK4-NEXT: [[#]]: {{0*}}[[#ADDR+1]] 0 NOTYPE GLOBAL DEFAULT 3 FOO_DATA_END
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## OVERWRITE_SECTIONS describes a section used as an anchor of an insert command.
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## Place .foo.data as an orphan, then insert .foo.text after .foo.data.
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# RUN: ld.lld %t/insert.lds %t/overwrite3.lds %t/a.o -o %t5
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# RUN: llvm-readelf -S -s %t4 | FileCheck %s --check-prefix=CHECK5
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# CHECK5: [Nr] Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK5-NEXT: [ 0] NULL [[#%x,]] [[#%x,]] 000000
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# CHECK5-NEXT: [ 1] .text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 4
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# CHECK5-NEXT: [ 2] .data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK5-NEXT: [ 3] .foo.data PROGBITS [[#%x,]] [[#%x,]] 000001 00 WA 0 0 1
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# CHECK5-NEXT: [ 4] .foo.text PROGBITS [[#%x,]] [[#%x,]] 000001 00 AX 0 0 1
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# CHECK5-NEXT: [ 5] .comment PROGBITS {{.*}}
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#--- a.s
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.globl _start
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_start:
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.section .foo.text,"ax"; .byte 1
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.section .foo.data,"aw"; .byte 2
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.section .text.1,"ax"; .byte 3
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.section .data.1,"aw"; .byte 4
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#--- main.lds
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SECTIONS {
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.data : { *(.data*) }
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.foo.data : { *(.foo.data) }
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.text : { *(.text*) }
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.foo.text : ALIGN(16) { *(.foo.text) }
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}
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#--- overwrite1.lds
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OVERWRITE_SECTIONS {
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.foo.text : ALIGN(8) { *(.foo.data .foo.text) }
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}
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#--- overwrite2.lds
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OVERWRITE_SECTIONS {
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.foo.data : { FOO_DATA_START = .; *(.foo.data) FOO_DATA_END = .; }
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.foo.text : { FOO_TEXT_START = .; *(.foo.text) FOO_TEXT_END = .; }
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}
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#--- overwrite3.lds
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OVERWRITE_SECTIONS {
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.foo.data : {}
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}
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#--- insert.lds
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SECTIONS { .foo.text : {} } INSERT AFTER .foo.data;
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#--- err1.lds
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## TODO Fix the diagnostic 'malformed number'
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# RUN: not ld.lld %t/err1.lds %t/a.o -o /dev/null 2>&1 | FileCheck %s -DFILE=%t/err1.lds --check-prefix=ERR1
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# ERR1: error: [[FILE]]:[[#@LINE+2]]: malformed number: =
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OVERWRITE_SECTIONS {
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A = 1;
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}
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