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160 changes: 73 additions & 87 deletions winsup/cygwin/autoload.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -64,44 +64,34 @@ bool NO_COPY wsock_started;
* DLL name (n bytes) asciz string containing the name of the DLL.
*/

/* LoadDLLprime is used to prime the DLL info information, providing an
additional initialization routine to call prior to calling the first
function. */
#if defined(__x86_64__)
#define LoadDLLprime(dllname, init_also, no_resolve_on_fork) __asm__ (" \n\
.ifndef " #dllname "_primed \n\
.section .data_cygwin_nocopy,\"w\" \n\
.align 8 \n\
."#dllname "_info: \n\
.quad _std_dll_init \n\
.quad " #no_resolve_on_fork " \n\
.long -1 \n\
.align 8 \n\
.quad " #init_also " \n\
.string16 \"" #dllname ".dll\" \n\
.text \n\
.set " #dllname "_primed, 1 \n\
.endif \n\
");
# define WORD64 ".quad"
#elif defined(__aarch64__)
#define LoadDLLprime(dllname, init_also, no_resolve_on_fork) __asm__ ( "\n\
# define WORD64 ".xword"
#else
# error unimplemented for this target
#endif

/* LoadDLLprime is used to prime the DLL info information, providing an
additional initialization routine to call prior to calling the first
function. WORD64 stands in for .quad/.xword, and .balign (which means
"align to N bytes" on both targets - "x64" and "arm64) is used for
alignment. */
#define LoadDLLprime(dllname, init_also, no_resolve_on_fork) __asm__ ("\n\
.ifndef " #dllname "_primed \n\
.section .data_cygwin_nocopy,\"w\" \n\
.balign 8 \n\
." #dllname "_info: \n\
.xword _std_dll_init \n\
.xword " #no_resolve_on_fork " \n\
.long -1 \n\
.balign 8 \n\
.xword " #init_also " \n\
.balign 8 \n\
." #dllname "_info: \n\
" WORD64 " _std_dll_init \n\
" WORD64 " " #no_resolve_on_fork " \n\
.long -1 \n\
.balign 8 \n\
" WORD64 " " #init_also " \n\
.string16 \"" #dllname ".dll\" \n\
.text \n\
.text \n\
.set " #dllname "_primed, 1 \n\
.endif \n\
.endif \n\
");
#else
#error unimplemented for this target
#endif

/* Standard DLL load macro. May invoke a fatal error if the function isn't
found. */
Expand Down Expand Up @@ -149,28 +139,28 @@ _win32_" #name ": \n\
.p2align 4 \n\
" #name ": \n\
_win32_" #name ": \n\
adr x16, 3f \n\
ldr x16, [x16] \n\
br x16 \n\
adr x16, 3f // x16 = &func_addr slot (label 3 == func_info+12)\n\
ldr x16, [x16] // x16 = *(&func_addr) = 1b first time, real addr later\n\
br x16 // fast-path branch into the resolved DLL func\n\
1: \n\
sub sp, sp, #80 \n\
sub sp, sp, #80 // reserve 80B frame for caller's arg regs + LR\n\
stp x0, x1, [sp, #0] \n\
stp x2, x3, [sp, #16] \n\
stp x4, x5, [sp, #32] \n\
stp x6, x7, [sp, #48] \n\
stp x8, x30, [sp, #64] \n\
adr x16, 2f \n\
ldur x17, [x16] \n\
ldr x17, [x17] \n\
blr x17 \n\
stp x8, x30, [sp, #64] // x30 here == label 2 == &func_info\n\
adr x16, 2f // x16 = &func_info\n\
ldr x17, [x16] // x17 = func_info->dll (= dll_info*)\n\
ldr x17, [x17] // x17 = dll_info->load_state (e.g. _std_dll_init)\n\
blr x17 // call thunk; LR = label 2 = arg to std_dll_init\n\
2: \n\
.xword ." #dllname "_info \n\
.hword " #notimp " \n\
.hword ((" #err ") & 0xffff) \n\
3: \n\
.xword 1b \n\
.asciz \"" #name "\" \n\
.text \n\
.xword ." #dllname "_info // +0 func_info.dll\n\
.hword " #notimp " // +8 func_info.decoration[lo]\n\
.hword ((" #err ") & 0xffff) // +10 func_info.decoration[hi]\n\
3: \n\
.xword 1b // +12 func_info.func_addr (patched by dll_func_load)\n\
.asciz \"" #name "\" // +20 func_info.name (asciz)\n\
.text \n\
");
#else
#error unimplemented for this target
Expand Down Expand Up @@ -261,55 +251,51 @@ msg1: \n\
\n\
.text \n\
.p2align 2 \n\
noload: \n\
ldr x2, [sp] // func_info* \n\
ldr w3, [x2, #8] // decoration \n\
tbz w3, #0, 1f \n\
\n\
asr w4, w3, #16 \n\
str w4, [sp, #8] \n\
mov w0, #127 // ERROR_PROC_NOT_FOUND \n\
noload: \n\
ldr x2, [sp] // x2 = func_info* (pushed by dll_chain)\n\
ldr w3, [x2, #8] // w3 = func_info.decoration\n\
tbz w3, #0, 1f // notimp bit clear -> fatal\n\
asr w4, w3, #16 // w4 = err (sign-extend high half)\n\
str w4, [sp, #8] // spill into dll_chain's xzr slot\n\
mov w0, #127 // ERROR_PROC_NOT_FOUND\n\
bl SetLastError \n\
ldr w0, [sp, #8] \n\
ldr x30, [sp, #88] \n\
add sp, sp, #96 \n\
ret \n\
1: \n\
add x1, x2, #20 \n\
ldur x3, [x2] \n\
ldr x2, [x3, #8] \n\
adrp x0, msg1 \n\
add x0, x0, #:lo12:msg1 \n\
bl api_fatal \n\
ldr w0, [sp, #8] // reload err as return value\n\
ldr x30, [sp, #88] // restore caller LR (16 + 72)\n\
add sp, sp, #96 // drop dll_chain (16) + trampoline (80) frames\n\
ret \n\
1: \n\
add x1, x2, #20 // x1 = &func_info.name\n\
ldr x3, [x2] // x3 = dll_info*\n\
ldr x2, [x3, #8] // x2 = dll_info->handle\n\
adrp x0, msg1 \n\
add x0, x0, #:lo12:msg1\n\
bl api_fatal // never returns \n\
\n\
.globl dll_func_load \n\
dll_func_load: \n\
ldr x2, [sp] \n\
ldur x3, [x2] \n\
ldr x0, [x3, #8] \n\
add x1, x2, #20 \n\
dll_func_load: \n\
ldr x2, [sp] // x2 = func_info* (pushed by dll_chain)\n\
ldr x3, [x2] // x3 = dll_info*\n\
ldr x0, [x3, #8] // x0 = dll handle (arg1 to GetProcAddress)\n\
add x1, x2, #20 // x1 = &func_info.name (arg2)\n\
bl GetProcAddress \n\
cbz x0, noload \n\
\n\
ldr x2, [sp] \n\
add x3, x2, #12 \n\
str x0, [x3] \n\
\n\
sub x16, x2, #52 \n\
\n\
add sp, sp, #16 \n\
ldp x0, x1, [sp, #0] \n\
cbz x0, noload // 0 -> not found, jump to error path\n\
ldr x2, [sp] // reload func_info*\n\
str x0, [x2, #12] // patch func_addr slot (label 3)\n\
sub x16, x2, #52 // x16 = trampoline entry; '#52' = 12B prologue\n\
// + 40B slow path; sync with LoadDLLfuncEx3\n\
add sp, sp, #16 // drop dll_chain frame\n\
ldp x0, x1, [sp, #0] // restore caller's arg regs\n\
ldp x2, x3, [sp, #16] \n\
ldp x4, x5, [sp, #32] \n\
ldp x6, x7, [sp, #48] \n\
ldp x8, x30, [sp, #64] \n\
add sp, sp, #80 \n\
br x16 \n\
ldp x8, x30, [sp, #64]\n\
add sp, sp, #80 // drop trampoline frame\n\
br x16 // re-enter trampoline; fast path now hits real func\n\
\n\
.global dll_chain \n\
dll_chain: \n\
stp x0, xzr, [sp, #-16]! \n\
br x1 \n\
stp x0, xzr, [sp, #-16]! // x0 = func_info* (= ret.high); push for dll_func_load\n\
br x1 // x1 = dll->init (= ret.low); tail-call resolver\n\
");
#else
#error unimplemented for this target
Expand Down Expand Up @@ -781,4 +767,4 @@ LoadDLLfunc (PdhAddEnglishCounterW, pdh)
LoadDLLfunc (PdhCollectQueryData, pdh)
LoadDLLfunc (PdhGetFormattedCounterValue, pdh)
LoadDLLfunc (PdhOpenQueryW, pdh)
}
}