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hanchenye-llvm-project/lld/test/COFF/string-tail-merge.s

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COFF: Implement string tail merging. In COFF, duplicate string literals are merged by placing them in a comdat whose leader symbol name contains a specific prefix followed by the hash and partial contents of the string literal. This gives us an easy way to identify sections containing string literals in the linker: check for leader symbol names with the given prefix. Any sections that are identified in this way as containing string literals may be tail merged. We do so using the StringTableBuilder class, which is also used to tail merge string literals in the ELF linker. Tail merging is enabled only if ICF is enabled, as this provides a signal as to whether the user cares about binary size. Differential Revision: https://reviews.llvm.org/D44504 llvm-svn: 327668
2018-03-16 05:14:02 +08:00
# REQUIRES: x86
# RUN: llvm-mc -triple=x86_64-windows-msvc -filetype=obj -o %t.obj %s
# RUN: lld-link %t.obj /out:%t.exe /entry:main /subsystem:console
# RUN: llvm-objdump -s %t.exe | FileCheck %s
# CHECK: Contents of section .rdata:
# CHECK-NEXT: 140002000 68656c6c 6f20776f 726c6400 6fa26ca4 hello world.o.l.
# CHECK-NEXT: 140002010 0068656c 6c6f2077 6f726c64 00006865 .hello world..he
# CHECK-NEXT: 140002020 6c6c6f20 776f726c 64006800 65006c00 llo world.h.e.l.
# CHECK-NEXT: 140002030 6c006f00 20007700 6f007200 6c006400 l.o. .w.o.r.l.d.
# CHECK-NEXT: 140002040 0000 ..
# CHECK: Contents of section .text:
.globl main
main:
# CHECK-NEXT: 140003000 11200040 01000000 17200040 01000000
.8byte "??_C@_0M@LACCCNMM@hello?5world?$AA@"
.8byte "??_C@_05MCBCHHEJ@world?$AA@"
# CHECK-NEXT: 140003010 2a200040 01000000 36200040 01000000
.8byte "??_C@_1BI@HHJHKLLN@?$AAh?$AAe?$AAl?$AAl?$AAo?$AA?5?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
.8byte "??_C@_1M@NBBDDHIO@?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
# CHECK-NEXT: 140003020 00200040 01000000 0c200040 01000000
.8byte "??_D@not_a_string_literal"
.8byte "??_C@string_literal_with_relocs"
# CHECK-NEXT: 140003030 00100040 01000000 1e200040 01000000
.8byte "??_C@string_literal_in_wrong_section"
.8byte "??_C@overaligned_string_literal"
.section .rdata,"dr",discard,"??_C@_0M@LACCCNMM@hello?5world?$AA@"
.globl "??_C@_0M@LACCCNMM@hello?5world?$AA@"
"??_C@_0M@LACCCNMM@hello?5world?$AA@":
.asciz "hello world"
.section .rdata,"dr",discard,"??_C@_05MCBCHHEJ@world?$AA@"
.globl "??_C@_05MCBCHHEJ@world?$AA@"
"??_C@_05MCBCHHEJ@world?$AA@":
.asciz "world"
.section .rdata,"dr",discard,"??_C@_1BI@HHJHKLLN@?$AAh?$AAe?$AAl?$AAl?$AAo?$AA?5?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
.globl "??_C@_1BI@HHJHKLLN@?$AAh?$AAe?$AAl?$AAl?$AAo?$AA?5?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
.p2align 1
"??_C@_1BI@HHJHKLLN@?$AAh?$AAe?$AAl?$AAl?$AAo?$AA?5?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@":
.short 104
.short 101
.short 108
.short 108
.short 111
.short 32
.short 119
.short 111
.short 114
.short 108
.short 100
.short 0
.section .rdata,"dr",discard,"??_C@_1M@NBBDDHIO@?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
.globl "??_C@_1M@NBBDDHIO@?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@"
.p2align 1
"??_C@_1M@NBBDDHIO@?$AAw?$AAo?$AAr?$AAl?$AAd?$AA?$AA@":
.short 119
.short 111
.short 114
.short 108
.short 100
.short 0
.section .data,"drw",discard,"??_C@string_literal_in_wrong_section"
.globl "??_C@string_literal_in_wrong_section"
"??_C@string_literal_in_wrong_section":
.asciz "hello world"
.section .rdata,"dr",discard,"??_D@not_a_string_literal"
.globl "??_D@not_a_string_literal"
"??_D@not_a_string_literal":
.asciz "hello world"
.section .rdata,"dr",discard,"??_C@string_literal_with_relocs"
.globl "??_C@string_literal_with_relocs"
"??_C@string_literal_with_relocs":
.4byte main + 111 + (114 << 8) + (108 << 16) + (100 << 24) # main + "orld"
.byte 0
.section .rdata,"dr",discard,"??_C@overaligned_string_literal"
.globl "??_C@overaligned_string_literal"
.p2align 1
"??_C@overaligned_string_literal":
.asciz "hello world"