diff options
| author | qmuntal <quimmuntal@gmail.com> | 2024-02-12 12:38:37 +0100 |
|---|---|---|
| committer | Quim Muntal <quimmuntal@gmail.com> | 2024-02-19 07:24:08 +0000 |
| commit | 35fa852d6dda69ce367e449fff78b3fc09834c97 (patch) | |
| tree | 60c0b405754a4ce87602174de600fb61a155403c /src/runtime/sys_windows_amd64.s | |
| parent | af5943f90cc919c38188067bbe006bdc148b576c (diff) | |
| download | go-35fa852d6dda69ce367e449fff78b3fc09834c97.tar.xz | |
runtime: use the right number of parameters in syscall_SyscallX on Windows
The syscall_SyscallX functions currently discard the nargs parameter
when calling syscall_SyscallN. This precludes some optimizations
down the line. For example, on amd64, a syscall that takes 0 arguments
don't need to set any of the params passing registers (CX, DX, R8, and
R9).
This CL updates all syscall_SyscallX functions so they call
syscall_SyscallN with an argument slice of the right length.
While here, remove the hack in syscall_SyscallN to support less than 4
arguments, and update instead asmstdcall on amd64 to properly handle
this case.
Change-Id: I0328e14f34c2b000fde06cc6a579b09e8c32f2b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/563315
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Run-TryBot: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Diffstat (limited to 'src/runtime/sys_windows_amd64.s')
| -rw-r--r-- | src/runtime/sys_windows_amd64.s | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s index c1b78e3976..56a2dc0bcf 100644 --- a/src/runtime/sys_windows_amd64.s +++ b/src/runtime/sys_windows_amd64.s @@ -33,14 +33,12 @@ TEXT runtime·asmstdcall(SB),NOSPLIT,$16 SUBQ $(const_maxArgs*8), SP // room for args - // Fast version, do not store args on the stack nor - // load them into registers. - CMPL CX, $0 - JE docall - // Fast version, do not store args on the stack. - CMPL CX, $4 - JLE loadregs + CMPL CX, $0; JE _0args + CMPL CX, $1; JE _1args + CMPL CX, $2; JE _2args + CMPL CX, $3; JE _3args + CMPL CX, $4; JE _4args // Check we have enough room for args. CMPL CX, $const_maxArgs @@ -53,22 +51,25 @@ TEXT runtime·asmstdcall(SB),NOSPLIT,$16 REP; MOVSQ MOVQ SP, SI -loadregs: // Load first 4 args into correspondent registers. - MOVQ 0(SI), CX - MOVQ 8(SI), DX - MOVQ 16(SI), R8 - MOVQ 24(SI), R9 // Floating point arguments are passed in the XMM // registers. Set them here in case any of the arguments // are floating point values. For details see // https://learn.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-170 - MOVQ CX, X0 - MOVQ DX, X1 - MOVQ R8, X2 +_4args: + MOVQ 24(SI), R9 MOVQ R9, X3 +_3args: + MOVQ 16(SI), R8 + MOVQ R8, X2 +_2args: + MOVQ 8(SI), DX + MOVQ DX, X1 +_1args: + MOVQ 0(SI), CX + MOVQ CX, X0 +_0args: -docall: // Call stdcall function. CALL AX |