76c0063eeb
String tables in unstripped executable files are fairly large in size. For example, lld's executable file is about 34.4 MB in my environment, and of which 3.5 MB is the string table. Efficiency of string table construction matters. Previously, the string table was built in an inefficient way. We used StringTableBuilder to build that and enabled string tail merging, although tail merging is not effective for the symbol table (you can only make the string table 0.3% smaller for lld.) Tail merging is computation intensive task and slow. This patch eliminates string tail merging. I changed the way of adding strings to the string table in this patch too. Previously, strings were added using add() and the same strings were then passed to getOffset() to get their offsets in the string table. In this way, getOffset() needs to look up a hash table to get offsets for given strings. This is a violation of "we look up the symbol table (or a hash table) only once for each symbol" dogma of the new LLD's design. Hash table lookup for long C++ mangled names is slow. I eliminated that lookup in this patch. In total, this patch improves link time of lld itself about 12% (3.50 seconds -> 3.08 seconds.) llvm-svn: 257017
120 lines
4.6 KiB
ArmAsm
120 lines
4.6 KiB
ArmAsm
# REQUIRES: x86
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# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
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# Empty SECTIONS command.
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# RUN: echo "SECTIONS {}" > %t.script
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# RUN: ld.lld -o %t1 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t1 | \
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# RUN: FileCheck -check-prefix=SEC-DEFAULT %s
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# SECTIONS command with the same order as default.
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# RUN: echo "SECTIONS { \
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# RUN: .text : { *(.text) } \
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# RUN: .data : { *(.data) } }" > %t.script
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# RUN: ld.lld -o %t2 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t2 | \
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# RUN: FileCheck -check-prefix=SEC-DEFAULT %s
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# Idx Name Size
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# SEC-DEFAULT: 1 .text 0000000e {{[0-9a-f]*}} TEXT DATA
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# SEC-DEFAULT: 2 .data 00000020 {{[0-9a-f]*}} DATA
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# SEC-DEFAULT: 3 other 00000003 {{[0-9a-f]*}} DATA
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# SEC-DEFAULT: 4 .bss 00000002 {{[0-9a-f]*}} BSS
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# SEC-DEFAULT: 5 .shstrtab 00000002 {{[0-9a-f]*}}
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# SEC-DEFAULT: 6 .symtab 00000030 {{[0-9a-f]*}}
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# SEC-DEFAULT: 7 .shstrtab 0000003c {{[0-9a-f]*}}
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# SEC-DEFAULT: 8 .strtab 00000008 {{[0-9a-f]*}}
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# Sections are put in order specified in linker script.
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# RUN: echo "SECTIONS { \
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# RUN: .bss : { *(.bss) } \
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# RUN: other : { *(other) } \
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# RUN: .shstrtab : { *(.shstrtab) } \
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# RUN: .symtab : { *(.symtab) } \
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# RUN: .strtab : { *(.strtab) } \
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# RUN: .data : { *(.data) } \
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# RUN: .text : { *(.text) } }" > %t.script
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# RUN: ld.lld -o %t3 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t3 | \
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# RUN: FileCheck -check-prefix=SEC-ORDER %s
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# Idx Name Size
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# SEC-ORDER: 1 .bss 00000002 {{[0-9a-f]*}} BSS
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# SEC-ORDER: 2 other 00000003 {{[0-9a-f]*}} DATA
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# SEC-ORDER: 3 .shstrtab 00000002 {{[0-9a-f]*}}
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# SEC-ORDER: 4 .shstrtab 0000003c {{[0-9a-f]*}}
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# SEC-ORDER: 5 .symtab 00000030 {{[0-9a-f]*}}
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# SEC-ORDER: 6 .strtab 00000008 {{[0-9a-f]*}}
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# SEC-ORDER: 7 .data 00000020 {{[0-9a-f]*}} DATA
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# SEC-ORDER: 8 .text 0000000e {{[0-9a-f]*}} TEXT DATA
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# .text and .data have swapped names but proper sizes and types.
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# RUN: echo "SECTIONS { \
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# RUN: .data : { *(.text) } \
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# RUN: .text : { *(.data) } }" > %t.script
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# RUN: ld.lld -o %t4 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t4 | \
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# RUN: FileCheck -check-prefix=SEC-SWAP-NAMES %s
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# Idx Name Size
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# SEC-SWAP-NAMES: 1 .data 0000000e {{[0-9a-f]*}} TEXT DATA
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# SEC-SWAP-NAMES: 2 .text 00000020 {{[0-9a-f]*}} DATA
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# SEC-SWAP-NAMES: 3 other 00000003 {{[0-9a-f]*}} DATA
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# SEC-SWAP-NAMES: 4 .bss 00000002 {{[0-9a-f]*}} BSS
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# SEC-SWAP-NAMES: 5 .shstrtab 00000002 {{[0-9a-f]*}}
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# SEC-SWAP-NAMES: 6 .symtab 00000030 {{[0-9a-f]*}}
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# SEC-SWAP-NAMES: 7 .shstrtab 0000003c {{[0-9a-f]*}}
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# SEC-SWAP-NAMES: 8 .strtab 00000008 {{[0-9a-f]*}}
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# .shstrtab from the input object file is discarded.
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# RUN: echo "SECTIONS { \
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# RUN: /DISCARD/ : { *(.shstrtab) } }" > %t.script
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# RUN: ld.lld -o %t5 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t5 | \
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# RUN: FileCheck -check-prefix=SEC-DISCARD %s
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# Idx Name Size
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# SEC-DISCARD: 1 .text 0000000e {{[0-9a-f]*}} TEXT DATA
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# SEC-DISCARD: 2 .data 00000020 {{[0-9a-f]*}} DATA
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# SEC-DISCARD: 3 other 00000003 {{[0-9a-f]*}} DATA
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# SEC-DISCARD: 4 .bss 00000002 {{[0-9a-f]*}} BSS
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# SEC-DISCARD: 5 .symtab 00000030 {{[0-9a-f]*}}
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# SEC-DISCARD: 6 .shstrtab 00000032 {{[0-9a-f]*}}
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# SEC-DISCARD: 7 .strtab 00000008 {{[0-9a-f]*}}
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# Multiple SECTIONS command specifying additional input section descriptions
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# for the same output section description - input sections are merged into
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# one output section.
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# RUN: echo "SECTIONS { \
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# RUN: .text : { *(.text) } \
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# RUN: .data : { *(.data) } } \
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# RUN: SECTIONS { \
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# RUN: .data : { *(other) } }" > %t.script
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# RUN: ld.lld -o %t6 --script %t.script %t
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# RUN: llvm-objdump -section-headers %t6 | \
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# RUN: FileCheck -check-prefix=SEC-MULTI %s
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# Idx Name Size
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# SEC-MULTI: 1 .text 0000000e {{[0-9a-f]*}} TEXT DATA
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# SEC-MULTI: 2 .data 00000023 {{[0-9a-f]*}} DATA
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# SEC-MULTI: 3 .bss 00000002 {{[0-9a-f]*}} BSS
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# SEC-MULTI: 4 .shstrtab 00000002 {{[0-9a-f]*}}
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# SEC-MULTI: 5 .symtab 00000030 {{[0-9a-f]*}}
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# SEC-MULTI: 6 .shstrtab 00000036 {{[0-9a-f]*}}
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# SEC-MULTI: 7 .strtab 00000008 {{[0-9a-f]*}}
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.globl _start;
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_start:
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mov $60, %rax
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mov $42, %rdi
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.section .data,"aw"
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.quad 10, 10, 20, 20
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.section other,"aw"
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.short 10
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.byte 20
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.section .shstrtab,""
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.short 20
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.section .bss,"",@nobits
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.short 0
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