cmd/cc, runtime: convert C compilers to use Go calling convention
To date, the C compilers and Go compilers differed only in how
values were returned from functions. This made it difficult to call
Go from C or C from Go if return values were involved. It also made
assembly called from Go and assembly called from C different.
This CL changes the C compiler to use the Go conventions, passing
results on the stack, after the arguments.
[Exception: this does not apply to C ... functions, because you can't
know where on the stack the arguments end.]
By doing this, the CL makes it possible to rewrite C functions into Go
one at a time, without worrying about which languages call that
function or which languages it calls.
This CL also updates all the assembly files in package runtime to use
the new conventions. Argument references of the form 40(SP) have
been rewritten to the form name+10(FP) instead, and there are now
Go func prototypes for every assembly function called from C or Go.
This means that 'go vet runtime' checks effectively every assembly
function, and go vet's output was used to automate the bulk of the
conversion.
Some functions, like seek and nsec on Plan 9, needed to be rewritten.
Many assembly routines called from C were reading arguments
incorrectly, using MOVL instead of MOVQ or vice versa, especially on
the less used systems like openbsd.
These were found by go vet and have been corrected too.
If we're lucky, this may reduce flakiness on those systems.
Tested on:
darwin/386
darwin/amd64
linux/arm
linux/386
linux/amd64
If this breaks another system, the bug is almost certainly in the
sys_$GOOS_$GOARCH.s file, since the rest of the CL is tested
by the combination of the above systems.
LGTM=dvyukov, iant
R=golang-codereviews, 0intro, dave, alex.brainman, dvyukov, iant
CC=golang-codereviews, josharian, r
https://golang.org/cl/135830043
diff --git a/src/pkg/runtime/sys_netbsd_arm.s b/src/pkg/runtime/sys_netbsd_arm.s
index acf01cf..bf133a2 100644
--- a/src/pkg/runtime/sys_netbsd_arm.s
+++ b/src/pkg/runtime/sys_netbsd_arm.s
@@ -28,11 +28,13 @@
MOVW 4(FP), R1
MOVW 8(FP), R2
SWI $0xa00005
+ MOVW R0, ret+12(FP)
RET
TEXT runtime·close(SB),NOSPLIT,$-8
MOVW 0(FP), R0
SWI $0xa00006
+ MOVW R0, ret+4(FP)
RET
TEXT runtime·read(SB),NOSPLIT,$-8
@@ -40,6 +42,7 @@
MOVW 4(FP), R1
MOVW 8(FP), R2
SWI $0xa00003
+ MOVW R0, ret+12(FP)
RET
TEXT runtime·write(SB),NOSPLIT,$-4
@@ -47,14 +50,16 @@
MOVW 4(FP), R1 // arg 2 - buf
MOVW 8(FP), R2 // arg 3 - nbyte
SWI $0xa00004 // sys_write
+ MOVW R0, ret+12(FP)
RET
// int32 lwp_create(void *context, uintptr flags, void *lwpid)
TEXT runtime·lwp_create(SB),NOSPLIT,$0
- MOVW context+0(FP), R0
+ MOVW ctxt+0(FP), R0
MOVW flags+4(FP), R1
MOVW lwpid+8(FP), R2
SWI $0xa00135 // sys__lwp_create
+ MOVW R0, ret+12(FP)
RET
TEXT runtime·osyield(SB),NOSPLIT,$0
@@ -67,16 +72,19 @@
MOVW 8(FP), R2 // arg 3 - hint
MOVW 12(FP), R3 // arg 4 - unparkhint
SWI $0xa001b2 // sys__lwp_park
+ MOVW R0, ret+16(FP)
RET
TEXT runtime·lwp_unpark(SB),NOSPLIT,$0
MOVW 0(FP), R0 // arg 1 - lwp
MOVW 4(FP), R1 // arg 2 - hint
SWI $0xa00141 // sys__lwp_unpark
+ MOVW R0, ret+8(FP)
RET
TEXT runtime·lwp_self(SB),NOSPLIT,$0
SWI $0xa00137 // sys__lwp_self
+ MOVW R0, ret+0(FP)
RET
TEXT runtime·lwp_tramp(SB),NOSPLIT,$0
@@ -153,9 +161,8 @@
ADD.S R2, R0
ADC R4, R1
- MOVW 0(FP), R3
- MOVW R0, 0(R3)
- MOVW R1, 4(R3)
+ MOVW R0, ret_lo+0(FP)
+ MOVW R1, ret_hi+4(FP)
RET
TEXT runtime·getcontext(SB),NOSPLIT,$-4
@@ -249,6 +256,7 @@
ADD $4, R13 // pass arg 5 and arg 6 on stack
SWI $0xa000c5 // sys_mmap
SUB $4, R13
+ MOVW R0, ret+24(FP)
RET
TEXT runtime·munmap(SB),NOSPLIT,$0
@@ -287,12 +295,14 @@
ADD $4, R13 // pass arg 5 and 6 on stack
SWI $0xa000ca // sys___sysctl
SUB $4, R13
+ MOVW R0, ret+24(FP)
RET
// int32 runtime·kqueue(void)
TEXT runtime·kqueue(SB),NOSPLIT,$0
SWI $0xa00158 // sys_kqueue
RSB.CS $0, R0
+ MOVW R0, ret+0(FP)
RET
// int32 runtime·kevent(int kq, Kevent *changelist, int nchanges, Kevent *eventlist, int nevents, Timespec *timeout)
@@ -309,6 +319,7 @@
SWI $0xa001b3 // sys___kevent50
RSB.CS $0, R0
SUB $4, R13
+ MOVW R0, ret+24(FP)
RET
// void runtime·closeonexec(int32 fd)
