runtime: change amd64 startup convention
Now the default startup is that the program begins at _rt0_amd64_$GOOS,
which sets DI = argc, SI = argv and jumps to _rt0_amd64.
This makes the _rt0_amd64 entry match the expected semantics for
the standard C "main" function, which we can now provide for use when
linking against a standard C library.
R=golang-dev, devon.odell, minux.ma
CC=golang-dev
https://golang.org/cl/7525043
diff --git a/src/pkg/runtime/asm_amd64.s b/src/pkg/runtime/asm_amd64.s
index 696befd..a671f39 100644
--- a/src/pkg/runtime/asm_amd64.s
+++ b/src/pkg/runtime/asm_amd64.s
@@ -6,8 +6,8 @@
TEXT _rt0_amd64(SB),7,$-8
// copy arguments forward on an even stack
- MOVQ 0(DI), AX // argc
- LEAQ 8(DI), BX // argv
+ MOVQ DI, AX // argc
+ MOVQ SI, BX // argv
SUBQ $(4*8+7), SP // 2args 2auto
ANDQ $~15, SP
MOVQ AX, 16(SP)
diff --git a/src/pkg/runtime/rt0_darwin_amd64.s b/src/pkg/runtime/rt0_darwin_amd64.s
index 4cfab58..45e69a0 100644
--- a/src/pkg/runtime/rt0_darwin_amd64.s
+++ b/src/pkg/runtime/rt0_darwin_amd64.s
@@ -2,9 +2,12 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// Darwin and Linux use the same linkage to main
-
TEXT _rt0_amd64_darwin(SB),7,$-8
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
MOVQ $_rt0_amd64(SB), AX
- MOVQ SP, DI
JMP AX
diff --git a/src/pkg/runtime/rt0_freebsd_amd64.s b/src/pkg/runtime/rt0_freebsd_amd64.s
index 5d2eeee..e6c6fb9 100644
--- a/src/pkg/runtime/rt0_freebsd_amd64.s
+++ b/src/pkg/runtime/rt0_freebsd_amd64.s
@@ -2,8 +2,12 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// Darwin and Linux use the same linkage to main
-
TEXT _rt0_amd64_freebsd(SB),7,$-8
- MOVQ $_rt0_amd64(SB), DX
- JMP DX
+ LEAQ 8(DI), SI // argv
+ MOVQ 0(DI), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
+ MOVQ $_rt0_amd64(SB), AX
+ JMP AX
diff --git a/src/pkg/runtime/rt0_linux_amd64.s b/src/pkg/runtime/rt0_linux_amd64.s
index dac9ae1..dfc9c04 100644
--- a/src/pkg/runtime/rt0_linux_amd64.s
+++ b/src/pkg/runtime/rt0_linux_amd64.s
@@ -2,9 +2,12 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-// Darwin and Linux use the same linkage to main
-
TEXT _rt0_amd64_linux(SB),7,$-8
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
MOVQ $_rt0_amd64(SB), AX
- MOVQ SP, DI
JMP AX
diff --git a/src/pkg/runtime/rt0_netbsd_amd64.s b/src/pkg/runtime/rt0_netbsd_amd64.s
index 85482b9..245a4c0f 100644
--- a/src/pkg/runtime/rt0_netbsd_amd64.s
+++ b/src/pkg/runtime/rt0_netbsd_amd64.s
@@ -2,7 +2,12 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-TEXT _rt0_amd64_netbsd(SB),7,$-8
- MOVQ $_rt0_amd64(SB), DX
- MOVQ SP, DI
- JMP DX
+TEXT _rt0_amd64_openbsd(SB),7,$-8
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
+ MOVQ $_rt0_amd64(SB), AX
+ JMP AX
diff --git a/src/pkg/runtime/rt0_openbsd_amd64.s b/src/pkg/runtime/rt0_openbsd_amd64.s
index e7fce59..245a4c0f 100644
--- a/src/pkg/runtime/rt0_openbsd_amd64.s
+++ b/src/pkg/runtime/rt0_openbsd_amd64.s
@@ -3,6 +3,11 @@
// license that can be found in the LICENSE file.
TEXT _rt0_amd64_openbsd(SB),7,$-8
- MOVQ $_rt0_amd64(SB), DX
- MOVQ SP, DI
- JMP DX
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
+ MOVQ $_rt0_amd64(SB), AX
+ JMP AX
diff --git a/src/pkg/runtime/rt0_plan9_amd64.s b/src/pkg/runtime/rt0_plan9_amd64.s
index 2b1fa2a..16e5e82 100644
--- a/src/pkg/runtime/rt0_plan9_amd64.s
+++ b/src/pkg/runtime/rt0_plan9_amd64.s
@@ -2,9 +2,10 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-TEXT _rt0_amd64_plan9(SB),7, $0
+TEXT _rt0_amd64_plan9(SB),7,$-8
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
MOVQ $_rt0_amd64(SB), AX
- MOVQ SP, DI
JMP AX
DATA runtime·isplan9(SB)/4, $1
diff --git a/src/pkg/runtime/rt0_windows_amd64.s b/src/pkg/runtime/rt0_windows_amd64.s
index dc1408a..4fc61dc 100644
--- a/src/pkg/runtime/rt0_windows_amd64.s
+++ b/src/pkg/runtime/rt0_windows_amd64.s
@@ -4,9 +4,14 @@
#include "zasm_GOOS_GOARCH.h"
-TEXT _rt0_amd64_windows(SB),7,$-8
+TEXT _rt0_amd64_darwin(SB),7,$-8
+ LEAQ 8(SP), SI // argv
+ MOVQ 0(SP), DI // argc
+ MOVQ $main(SB), AX
+ JMP AX
+
+TEXT main(SB),7,$-8
MOVQ $_rt0_amd64(SB), AX
- MOVQ SP, DI
JMP AX
DATA runtime·iswindows(SB)/4, $1
