7f0e6c31c2
Allow disabling either the full auto import feature, or just forbidding the cases that require runtime fixups. As long as all auto imported variables are referenced from separate .refptr$<name> sections, we can alias them on top of the IAT entries and don't actually need any runtime fixups via pseudo relocations. LLVM generates references to variables in .refptr stubs, if it isn't known that the variable for sure is defined in the same object module. Runtime pseudo relocs are needed if the addresses of auto imported variables are used in constant initializers though. Fixing up runtime pseudo relocations requires the use of VirtualProtect (which is disallowed in WinStore/UWP apps) or VirtualProtectFromApp. To allow any risk of ambiguity, allow rejecting cases that would require this at the linker stage. This adds support for the --disable-runtime-pseudo-reloc and --disable-auto-import options in the MinGW driver (matching GNU ld.bfd) with corresponding lld private options in the COFF driver. Differential Revision: https://reviews.llvm.org/D78923
78 lines
2.8 KiB
ArmAsm
78 lines
2.8 KiB
ArmAsm
# REQUIRES: x86
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# RUN: echo -e ".global variable\n.global DllMainCRTStartup\n.text\nDllMainCRTStartup:\nret\n.data\nvariable:\n.long 42" > %t-lib.s
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# RUN: llvm-mc -triple=x86_64-windows-gnu %t-lib.s -filetype=obj -o %t-lib.obj
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# RUN: lld-link -out:%t-lib.dll -dll -entry:DllMainCRTStartup %t-lib.obj -lldmingw -implib:%t-lib.lib
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# RUN: llvm-mc -triple=x86_64-windows-gnu %s -defsym listptrs=1 -filetype=obj -o %t.obj
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# RUN: lld-link -lldmingw -out:%t.exe -entry:main %t.obj %t-lib.lib -verbose
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# RUN: llvm-readobj --coff-imports %t.exe | FileCheck -check-prefix=IMPORTS %s
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# RUN: llvm-objdump -d %t.exe | FileCheck --check-prefix=DISASM %s
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# RUN: llvm-objdump -s %t.exe | FileCheck --check-prefix=CONTENTS %s
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## Check that we can autoimport these variables with pseudo relocs disabled.
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# RUN: llvm-mc -triple=x86_64-windows-gnu %s -defsym listptrs=0 -filetype=obj -o %t.noptrs.obj
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# RUN: lld-link -lldmingw -runtime-pseudo-reloc:no -out:%t.exe -entry:main %t.noptrs.obj %t-lib.lib
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## Check that we can't autoimport them with autoimport disabled.
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# RUN: not lld-link -lldmingw -auto-import:no -out:%t.exe -entry:main %t.noptrs.obj %t-lib.lib 2>&1 | FileCheck --check-prefix=NO-AUTOIMPORT %s
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# IMPORTS: Import {
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# IMPORTS-NEXT: Name: autoimport-refptr.s.tmp-lib.dll
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# IMPORTS-NEXT: ImportLookupTableRVA: 0x2050
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# IMPORTS-NEXT: ImportAddressTableRVA: 0x2060
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# IMPORTS-NEXT: Symbol: variable (0)
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# IMPORTS-NEXT: }
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# DISASM: Disassembly of section .text:
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# DISASM-EMPTY:
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# DISASM: <.text>:
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# Relative offset at 0x1002 pointing at the IAT at 0x2060
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# DISASM: 140001000: 48 8b 05 59 10 00 00 movq 4185(%rip), %rax
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# DISASM: 140001007: 8b 00 movl (%rax), %eax
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# Relative offset at 0x100b pointing at the .refptr.localvar stub at
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# 0x2000
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# DISASM: 140001009: 48 8b 0d f0 0f 00 00 movq 4080(%rip), %rcx
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# DISASM: 140001010: 03 01 addl (%rcx), %eax
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# DISASM: 140001012: c3 retq
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# relocs: pointing at an empty list of runtime pseudo relocs.
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# localvar: 42
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# CONTENTS: Contents of section .data:
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# CONTENTS: 140003000 08200040 01000000 08200040 01000000
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# CONTENTS: 140003010 2a000000
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# NO-AUTOIMPORT: error: undefined symbol: variable
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.global main
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.global localvar
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.text
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main:
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movq .refptr.variable(%rip), %rax
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movl (%rax), %eax
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movq .refptr.localvar(%rip), %rcx
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addl (%rcx), %eax
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ret
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.data
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.if listptrs==1
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relocs:
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.quad __RUNTIME_PSEUDO_RELOC_LIST__
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.quad __RUNTIME_PSEUDO_RELOC_LIST_END__
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.endif
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localvar:
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.int 42
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# Normally the compiler wouldn't emit a stub for a variable that is
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# emitted in the same translation unit.
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.section .rdata$.refptr.localvar,"dr",discard,.refptr.localvar
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.global .refptr.localvar
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.refptr.localvar:
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.quad localvar
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.section .rdata$.refptr.variable,"dr",discard,.refptr.variable
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.global .refptr.variable
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.refptr.variable:
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.quad variable
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