diff options
| -rw-r--r-- | src/cmd/9g/ggen.c | 20 | ||||
| -rw-r--r-- | src/runtime/asm_power64x.s | 2 | ||||
| -rw-r--r-- | test/clearfat.go | 68 |
3 files changed, 82 insertions, 8 deletions
diff --git a/src/cmd/9g/ggen.c b/src/cmd/9g/ggen.c index c41d8eb41..7d9cf5050 100644 --- a/src/cmd/9g/ggen.c +++ b/src/cmd/9g/ggen.c @@ -900,7 +900,7 @@ ret: void clearfat(Node *nl) { - uint64 w, c, q, t; + uint64 w, c, q, t, boff; Node dst, end, r0, *f; Prog *p, *pl; @@ -944,6 +944,8 @@ clearfat(Node *nl) patch(gbranch(ABNE, T, 0), pl); regfree(&end); + // The loop leaves R3 on the last zeroed dword + boff = 8; } else if(q >= 4) { p = gins(ASUB, N, &dst); p->from.type = D_CONST; @@ -953,17 +955,21 @@ clearfat(Node *nl) afunclit(&p->to, f); // 4 and 128 = magic constants: see ../../runtime/asm_power64x.s p->to.offset = 4*(128-q); - } else - for(t = 0; t < q; t++) { - p = gins(AMOVD, &r0, &dst); - p->to.type = D_OREG; - p->to.offset = 8*t; + // duffzero leaves R3 on the last zeroed dword + boff = 8; + } else { + for(t = 0; t < q; t++) { + p = gins(AMOVD, &r0, &dst); + p->to.type = D_OREG; + p->to.offset = 8*t; + } + boff = 8*q; } for(t = 0; t < c; t++) { p = gins(AMOVB, &r0, &dst); p->to.type = D_OREG; - p->to.offset = t; + p->to.offset = t+boff; } reg[REGRT1]--; } diff --git a/src/runtime/asm_power64x.s b/src/runtime/asm_power64x.s index ab2db061c..2ad3e56e9 100644 --- a/src/runtime/asm_power64x.s +++ b/src/runtime/asm_power64x.s @@ -829,7 +829,7 @@ notfound: // in ../../cmd/9g/ggen.c:/^clearfat. // R0: always zero // R3 (aka REGRT1): ptr to memory to be zeroed - 8 -// R3 is updated as a side effect. +// On return, R3 points to the last zeroed dword. TEXT runtime·duffzero(SB), NOSPLIT, $-8-0 MOVDU R0, 8(R3) MOVDU R0, 8(R3) diff --git a/test/clearfat.go b/test/clearfat.go new file mode 100644 index 000000000..45d539306 --- /dev/null +++ b/test/clearfat.go @@ -0,0 +1,68 @@ +// runoutput + +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Check that {5,6,8,9}g/ggen.c:clearfat is zeroing the entire object. + +package main + +import ( + "bytes" + "fmt" + "strconv" + "strings" +) + +const ntest = 1100 + +func main() { + var decls, calls bytes.Buffer + + for i := 1; i <= ntest; i++ { + s := strconv.Itoa(i) + decls.WriteString(strings.Replace(decl, "$", s, -1)) + calls.WriteString(strings.Replace("poison$()\n\tclearfat$()\n\t", "$", s, -1)) + } + + program = strings.Replace(program, "$DECLS", decls.String(), 1) + program = strings.Replace(program, "$CALLS", calls.String(), 1) + fmt.Print(program) +} + +var program = `package main + +var count int + +$DECLS + +func main() { + $CALLS + if count != 0 { + println("failed", count, "case(s)") + } +} +` + +const decl = ` +func poison$() { + // Grow and poison the stack space that will be used by clearfat$ + var t [2*$]byte + for i := range t { + t[i] = 0xff + } +} + +func clearfat$() { + var t [$]byte + + for _, x := range t { + if x != 0 { +// println("clearfat$: index", i, "expected 0, got", x) + count++ + break + } + } +} +` |