all: delete riscv64 non-register ABI fallback path

Change-Id: I9e997b59ffb868575b780b9660df1f5ac322b79a
Reviewed-on: https://go-review.googlesource.com/c/go/+/443556
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: David Chase <drchase@google.com>

7 files changed, 5 insertions, 185 deletions

diff --git a/src/internal/bytealg/compare_riscv64.s b/src/internal/bytealg/compare_riscv64.s
index e616577d53..44a743d3af 100644
--- a/src/internal/bytealg/compare_riscv64.s
+++ b/src/internal/bytealg/compare_riscv64.s
@@ -6,13 +6,6 @@
 #include "textflag.h"
 
 TEXT ·Compare<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-56
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	a_base+0(FP), X10
-	MOV	a_len+8(FP), X11
-	MOV	b_base+24(FP), X12
-	MOV	b_len+32(FP), X13
-	MOV	$ret+48(FP), X14
-#else
 	// X10 = a_base
 	// X11 = a_len
 	// X12 = a_cap (unused)
@@ -21,17 +14,9 @@ TEXT ·Compare<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-56
 	// X15 = b_cap (unused)
 	MOV	X13, X12
 	MOV	X14, X13
-#endif
 	JMP	compare<>(SB)
 
 TEXT runtime·cmpstring<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-40
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	a_base+0(FP), X10
-	MOV	a_len+8(FP), X11
-	MOV	b_base+16(FP), X12
-	MOV	b_len+24(FP), X13
-	MOV	$ret+32(FP), X14
-#endif
 	// X10 = a_base
 	// X11 = a_len
 	// X12 = b_base
@@ -199,7 +184,4 @@ cmp:
 	SLTU	X8, X9, X6
 cmp_ret:
 	SUB	X5, X6, X10
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X10, (X14)
-#endif
 	RET
diff --git a/src/internal/bytealg/count_riscv64.s b/src/internal/bytealg/count_riscv64.s
index a15d07d768..d123cbd7c6 100644
--- a/src/internal/bytealg/count_riscv64.s
+++ b/src/internal/bytealg/count_riscv64.s
@@ -6,17 +6,11 @@
 #include "textflag.h"
 
 TEXT ·Count<ABIInternal>(SB),NOSPLIT,$0-40
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	b_base+0(FP), X10
-	MOV	b_len+8(FP), X11
-	MOVBU	c+24(FP), X12	// byte to count
-#else
 	// X10 = b_base
 	// X11 = b_len
 	// X12 = b_cap (unused)
 	// X13 = byte to count (want in X12)
 	AND	$0xff, X13, X12
-#endif
 	MOV	ZERO, X14	// count
 	ADD	X10, X11	// end
 
@@ -29,19 +23,10 @@ loop:
 	JMP	loop
 
 done:
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X14, ret+32(FP)
-#else
 	MOV	X14, X10
-#endif
 	RET
 
 TEXT ·CountString<ABIInternal>(SB),NOSPLIT,$0-32
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	s_base+0(FP), X10
-	MOV	s_len+8(FP), X11
-	MOVBU	c+16(FP), X12	// byte to count
-#endif
 	// X10 = s_base
 	// X11 = s_len
 	// X12 = byte to count
@@ -58,9 +43,5 @@ loop:
 	JMP	loop
 
 done:
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X14, ret+24(FP)
-#else
 	MOV	X14, X10
-#endif
 	RET
diff --git a/src/internal/bytealg/equal_riscv64.s b/src/internal/bytealg/equal_riscv64.s
index 1e070beb3e..3834083ec9 100644
--- a/src/internal/bytealg/equal_riscv64.s
+++ b/src/internal/bytealg/equal_riscv64.s
@@ -9,12 +9,6 @@
 
 // func memequal(a, b unsafe.Pointer, size uintptr) bool
 TEXT runtime·memequal<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	a+0(FP), X10
-	MOV	b+8(FP), X11
-	MOV	size+16(FP), X12
-	MOV	$ret+24(FP), X13
-#endif
 	// X10 = a_base
 	// X11 = b_base
 	// X12 = size
@@ -23,11 +17,6 @@ TEXT runtime·memequal<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25
 // func memequal_varlen(a, b unsafe.Pointer) bool
 TEXT runtime·memequal_varlen<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-17
 	MOV	8(CTXT), X12    // compiler stores size at offset 8 in the closure
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	a+0(FP), X10
-	MOV	b+8(FP), X11
-	MOV	$ret+16(FP), X13
-#endif
 	// X10 = a_base
 	// X11 = b_base
 	JMP	memequal<>(SB)
@@ -128,17 +117,8 @@ loop1:
 	JMP	loop1
 
 not_eq:
-#ifndef GOEXPERIMENT_regabiargs
-	MOVB	ZERO, (X13)
-#else
 	MOVB	ZERO, X10
-#endif
 	RET
 eq:
-#ifndef GOEXPERIMENT_regabiargs
 	MOV	$1, X10
-	MOVB	X10, (X13)
-#else
-	MOV	$1, X10
-#endif
 	RET
diff --git a/src/internal/bytealg/indexbyte_riscv64.s b/src/internal/bytealg/indexbyte_riscv64.s
index a20396592b..8be78ed950 100644
--- a/src/internal/bytealg/indexbyte_riscv64.s
+++ b/src/internal/bytealg/indexbyte_riscv64.s
@@ -6,11 +6,6 @@
 #include "textflag.h"
 
 TEXT ·IndexByte<ABIInternal>(SB),NOSPLIT,$0-40
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	b_base+0(FP), X10
-	MOV	b_len+8(FP), X11
-	MOVBU	c+24(FP), X13	// byte to find
-#endif
 	// X10 = b_base
 	// X11 = b_len
 	// X12 = b_cap (unused)
@@ -27,24 +22,13 @@ loop:
 	BNE	X13, X14, loop
 
 	SUB	X12, X10		// remove base
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X10, ret+32(FP)
-#endif
 	RET
 
 notfound:
 	MOV	$-1, X10
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X10, ret+32(FP)
-#endif
 	RET
 
 TEXT ·IndexByteString<ABIInternal>(SB),NOSPLIT,$0-32
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	s_base+0(FP), X10
-	MOV	s_len+8(FP), X11
-	MOVBU	c+16(FP), X12	// byte to find
-#endif
 	// X10 = b_base
 	// X11 = b_len
 	// X12 = byte to find
@@ -60,14 +44,8 @@ loop:
 	BNE	X12, X14, loop
 
 	SUB	X13, X10		// remove base
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X10, ret+24(FP)
-#endif
 	RET
 
 notfound:
 	MOV	$-1, X10
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	X10, ret+24(FP)
-#endif
 	RET
diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s
index 389851beb9..31b81aea12 100644
--- a/src/runtime/asm_riscv64.s
+++ b/src/runtime/asm_riscv64.s
@@ -268,11 +268,7 @@ TEXT runtime·procyield(SB),NOSPLIT,$0-0
 
 // func mcall(fn func(*g))
 TEXT runtime·mcall<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-8
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	X10, CTXT
-#else
-	MOV	fn+0(FP), CTXT
-#endif
 
 	// Save caller state in g->sched
 	MOV	X2, (g_sched+gobuf_sp)(g)
@@ -644,7 +640,6 @@ TEXT ·checkASM(SB),NOSPLIT,$0-1
 	MOV	T0, ret+0(FP)
 	RET
 
-#ifdef GOEXPERIMENT_regabiargs
 // spillArgs stores return values from registers to a *internal/abi.RegArgs in X25.
 TEXT ·spillArgs(SB),NOSPLIT,$0-0
 	MOV	X10, (0*8)(X25)
@@ -716,13 +711,6 @@ TEXT ·unspillArgs(SB),NOSPLIT,$0-0
 	MOVD	(30*8)(X25), F22
 	MOVD	(31*8)(X25), F23
 	RET
-#else
-TEXT ·spillArgs(SB),NOSPLIT,$0-0
-	RET
-
-TEXT ·unspillArgs(SB),NOSPLIT,$0-0
-	RET
-#endif
 
 // gcWriteBarrier performs a heap pointer write and informs the GC.
 //
@@ -832,157 +820,72 @@ flush:
 // corresponding runtime handler.
 // The tail call makes these stubs disappear in backtraces.
 TEXT runtime·panicIndex<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicIndex<ABIInternal>(SB)
 TEXT runtime·panicIndexU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicIndexU<ABIInternal>(SB)
 TEXT runtime·panicSliceAlen<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceAlen<ABIInternal>(SB)
 TEXT runtime·panicSliceAlenU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceAlenU<ABIInternal>(SB)
 TEXT runtime·panicSliceAcap<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceAcap<ABIInternal>(SB)
 TEXT runtime·panicSliceAcapU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceAcapU<ABIInternal>(SB)
 TEXT runtime·panicSliceB<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceB<ABIInternal>(SB)
 TEXT runtime·panicSliceBU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceBU<ABIInternal>(SB)
 TEXT runtime·panicSlice3Alen<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T2, X10
 	MOV	T3, X11
-#else
-	MOV	T2, x+0(FP)
-	MOV	T3, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3Alen<ABIInternal>(SB)
 TEXT runtime·panicSlice3AlenU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T2, X10
 	MOV	T3, X11
-#else
-	MOV	T2, x+0(FP)
-	MOV	T3, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3AlenU<ABIInternal>(SB)
 TEXT runtime·panicSlice3Acap<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T2, X10
 	MOV	T3, X11
-#else
-	MOV	T2, x+0(FP)
-	MOV	T3, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3Acap<ABIInternal>(SB)
 TEXT runtime·panicSlice3AcapU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T2, X10
 	MOV	T3, X11
-#else
-	MOV	T2, x+0(FP)
-	MOV	T3, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3AcapU<ABIInternal>(SB)
 TEXT runtime·panicSlice3B<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3B<ABIInternal>(SB)
 TEXT runtime·panicSlice3BU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T1, X10
 	MOV	T2, X11
-#else
-	MOV	T1, x+0(FP)
-	MOV	T2, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3BU<ABIInternal>(SB)
 TEXT runtime·panicSlice3C<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3C<ABIInternal>(SB)
 TEXT runtime·panicSlice3CU<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T0, X10
 	MOV	T1, X11
-#else
-	MOV	T0, x+0(FP)
-	MOV	T1, y+8(FP)
-#endif
 	JMP	runtime·goPanicSlice3CU<ABIInternal>(SB)
 TEXT runtime·panicSliceConvert<ABIInternal>(SB),NOSPLIT,$0-16
-#ifdef GOEXPERIMENT_regabiargs
 	MOV	T2, X10
 	MOV	T3, X11
-#else
-	MOV	T2, x+0(FP)
-	MOV	T3, y+8(FP)
-#endif
 	JMP	runtime·goPanicSliceConvert<ABIInternal>(SB)
 
 DATA	runtime·mainPC+0(SB)/8,$runtime·main<ABIInternal>(SB)
diff --git a/src/runtime/memclr_riscv64.s b/src/runtime/memclr_riscv64.s
index 4cf0f5488f..d12b545b1e 100644
--- a/src/runtime/memclr_riscv64.s
+++ b/src/runtime/memclr_riscv64.s
@@ -8,10 +8,8 @@
 
 // void runtime·memclrNoHeapPointers(void*, uintptr)
 TEXT runtime·memclrNoHeapPointers<ABIInternal>(SB),NOSPLIT,$0-16
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	ptr+0(FP), X10
-	MOV	n+8(FP), X11
-#endif
+	// X10 = ptr
+	// X11 = n
 
 	// If less than 8 bytes, do single byte zeroing.
 	MOV	$8, X9
diff --git a/src/runtime/memmove_riscv64.s b/src/runtime/memmove_riscv64.s
index 538aee3642..79d90c1adb 100644
--- a/src/runtime/memmove_riscv64.s
+++ b/src/runtime/memmove_riscv64.s
@@ -8,11 +8,9 @@
 
 // void runtime·memmove(void*, void*, uintptr)
 TEXT runtime·memmove<ABIInternal>(SB),NOSPLIT,$-0-24
-#ifndef GOEXPERIMENT_regabiargs
-	MOV	to+0(FP), A0
-	MOV	from+8(FP), A1
-	MOV	n+16(FP), A2
-#endif
+	// A0 = to
+	// A1 = from
+	// A2 = n
 	ADD	A1, A2, T5
 
 	// If the destination is ahead of the source, start at the end of the