llvm-capstone/lld/test/COFF/autoimport-refptr.s
Martin Storsjo 7a41693898 [COFF] Provide __CTOR_LIST__ and __DTOR_LIST__ symbols for MinGW
MinGW uses these kind of list terminator symbols for traversing
the constructor/destructor lists. These list terminators are
actual pointers entries in the lists, with the values 0 and
(uintptr_t)-1 (instead of just symbols pointing to the start/end
of the list).

(This mechanism exists in both the mingw-w64 crt startup code and
in libgcc; normally the mingw-w64 one is used, but a DLL build of
libgcc uses the libgcc one. Therefore it's not trivial to change
the mechanism without lots of cross-project synchronization and
potentially invalidating some combinations of old/new versions
of them.)

When mingw-w64 has been used with lld so far, the CRT startup object
files have so far provided these symbols, ending up with different,
incompatible builds of the CRT startup object files depending on
whether binutils or lld are going to be used.

In order to avoid the need of different configuration of the CRT startup
object files depending on what linker to be used, provide these symbols
in lld instead. (Mingw-w64 checks at build time whether the linker
provides these symbols or not.) This unifies this particular detail
between the two linkers.

This does disallow the use of the very latest lld with older versions
of mingw-w64 (the configure check for the list was added recently;
earlier it simply checked whether the CRT was built with gcc or clang),
and requires rebuilding the mingw-w64 CRT. But the number of users of
lld+mingw still is low enough that such a change should be tolerable,
and unifies this aspect of the toolchains, easing interoperability
between the toolchains for the future.

The actual test for this feature is added in ctors_dtors_priority.s,
but a number of other tests that checked absolute output addresses
are updated.

Differential Revision: https://reviews.llvm.org/D52053

llvm-svn: 342294
2018-09-14 22:26:59 +00:00

66 lines
2.2 KiB
ArmAsm

# REQUIRES: x86
# RUN: echo -e ".global variable\n.global DllMainCRTStartup\n.text\nDllMainCRTStartup:\nret\n.data\nvariable:\n.long 42" > %t-lib.s
# RUN: llvm-mc -triple=x86_64-windows-gnu %t-lib.s -filetype=obj -o %t-lib.obj
# RUN: lld-link -out:%t-lib.dll -dll -entry:DllMainCRTStartup %t-lib.obj -lldmingw -implib:%t-lib.lib
# RUN: llvm-mc -triple=x86_64-windows-gnu %s -filetype=obj -o %t.obj
# RUN: lld-link -lldmingw -out:%t.exe -entry:main %t.obj %t-lib.lib -verbose
# RUN: llvm-readobj -coff-imports %t.exe | FileCheck -check-prefix=IMPORTS %s
# RUN: llvm-objdump -d %t.exe | FileCheck -check-prefix=DISASM %s
# RUN: llvm-objdump -s %t.exe | FileCheck -check-prefix=CONTENTS %s
# IMPORTS: Import {
# IMPORTS-NEXT: Name: autoimport-refptr.s.tmp-lib.dll
# IMPORTS-NEXT: ImportLookupTableRVA: 0x2050
# IMPORTS-NEXT: ImportAddressTableRVA: 0x2060
# IMPORTS-NEXT: Symbol: variable (0)
# IMPORTS-NEXT: }
# DISASM: Disassembly of section .text:
# DISASM: .text:
# Relative offset at 0x1002 pointing at the IAT at 0x2060
# DISASM: 140001000: 48 8b 05 59 10 00 00 movq 4185(%rip), %rax
# DISASM: 140001007: 8b 00 movl (%rax), %eax
# Relative offset at 0x100b pointing at the .refptr.localvar stub at
# 0x2000
# DISASM: 140001009: 48 8b 0d f0 0f 00 00 movq 4080(%rip), %rcx
# DISASM: 140001010: 03 01 addl (%rcx), %eax
# DISASM: 140001012: c3 retq
# relocs: pointing at an empty list of runtime pseudo relocs.
# localvar: 42
# CONTENTS: Contents of section .data:
# CONTENTS: 140003000 08200040 01000000 08200040 01000000
# CONTENTS: 140003010 2a000000
.global main
.global localvar
.text
main:
movq .refptr.variable(%rip), %rax
movl (%rax), %eax
movq .refptr.localvar(%rip), %rcx
addl (%rcx), %eax
ret
.data
relocs:
.quad __RUNTIME_PSEUDO_RELOC_LIST__
.quad __RUNTIME_PSEUDO_RELOC_LIST_END__
localvar:
.int 42
# Normally the compiler wouldn't emit a stub for a variable that is
# emitted in the same translation unit.
.section .rdata$.refptr.localvar,"dr",discard,.refptr.localvar
.global .refptr.localvar
.refptr.localvar:
.quad localvar
.section .rdata$.refptr.variable,"dr",discard,.refptr.variable
.global .refptr.variable
.refptr.variable:
.quad variable