code improvement

better calling of morestack

R=r
OCL=28179
CL=28179

diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c
index 5f155ea2ebdc1ba6b1e685a4aba65665d68948c3..b26db1dcd6ab1272b68f5f21a4d30fb6bc7a5f05 100644 (file)
--- a/src/cmd/6l/pass.c
+++ b/src/cmd/6l/pass.c
@@ -483,24 +483,34 @@ dostkoff(void)
        Prog *p, *q, *q1;
        int32 autoffset, deltasp;
        int a, f, curframe, curbecome, maxbecome, pcsize;
-       Prog *pmorestack;
-       Sym *symmorestack;
+       Prog *pmorestack00, *pmorestack01, *pmorestack10, *pmorestack11;
+       Sym *symmorestack00, *symmorestack01, *symmorestack10, *symmorestack11;
+       uint32 moreconst1, moreconst2;
 
-       pmorestack = P;
-       symmorestack = lookup("sys·morestack", 0);
+       pmorestack00 = P;
+       pmorestack01 = P;
+       pmorestack10 = P;
+       pmorestack11 = P;
+
+       symmorestack00 = lookup("sys·morestack00", 0);
+       symmorestack01 = lookup("sys·morestack01", 0);
+       symmorestack10 = lookup("sys·morestack10", 0);
+       symmorestack11 = lookup("sys·morestack11", 0);
 
-       if(symmorestack->type == STEXT)
        for(p = firstp; p != P; p = p->link) {
                if(p->as == ATEXT) {
-                       if(p->from.sym == symmorestack) {
-                               pmorestack = p;
-                               p->from.scale |= NOSPLIT;
-                               break;
-                       }
+                       if(p->from.sym == symmorestack00)
+                               pmorestack00 = p;
+                       if(p->from.sym == symmorestack01)
+                               pmorestack01 = p;
+                       if(p->from.sym == symmorestack10)
+                               pmorestack10 = p;
+                       if(p->from.sym == symmorestack11)
+                               pmorestack11 = p;
                }
        }
-       if(pmorestack == P)
-               diag("sys·morestack not defined");
+       if(pmorestack00 == P || pmorestack01 == P || pmorestack10 == P || pmorestack11 == P)
+               diag("sys·morestack[01][01] not defined");
 
        curframe = 0;
        curbecome = 0;
@@ -583,14 +593,14 @@ dostkoff(void)
 
                        q = P;
                        q1 = P;
-                       if(pmorestack != P)
                        if(!(p->from.scale & NOSPLIT)) {
                                if(debug['K']) {
                                        // 6l -K means check not only for stack
                                        // overflow but stack underflow.
                                        // On underflow, INT 3 (breakpoint).
                                        // Underflow itself is rare but this also
-                                       // catches out-of-sync stack guard info.
+                                       // catches out-of-sync stack guard info
+
                                        p = appendp(p);
                                        p->as = ACMPQ;
                                        p->from.type = D_INDIR+D_R15;
@@ -646,33 +656,73 @@ dostkoff(void)
                                        q = p;
                                }
 
-                               p = appendp(p);
-                               p->as = AMOVQ;
-                               p->from.type = D_CONST;
-                               p->from.offset = 0;
-                               p->to.type = D_AX;
-                               if(q1) {
-                                       q1->pcond = p;
-                                       q1 = P;
-                               }
-
                                /* 160 comes from 3 calls (3*8) 4 safes (4*8) and 104 guard */
+                               moreconst1 = 0;
                                if(autoffset+160 > 4096)
-                                       p->from.offset = (autoffset+160) & ~7LL;
-                               p->from.offset |= textarg<<32;
+                                       moreconst1 = (autoffset+160) & ~7LL;
+                               moreconst2 = textarg;
 
+                               // four varieties (const1==0 cross const2==0)
                                p = appendp(p);
-                               p->as = AMOVQ;
-                               p->from.type = D_AX;
-                               p->to.type = D_INDIR+D_R14;
-                               p->to.offset = 8;
+                               if(moreconst1 == 0 && moreconst2 == 0) {
+                                       p->as = ACALL;
+                                       p->to.type = D_BRANCH;
+                                       p->pcond = pmorestack00;
+                                       p->to.sym = symmorestack00;
+                                       if(q1) {
+                                               q1->pcond = p;
+                                               q1 = P;
+                                       }
+                               } else
+                               if(moreconst1 != 0 && moreconst2 == 0) {
+                                       p->as = AMOVL;
+                                       p->from.type = D_CONST;
+                                       p->from.offset = moreconst1;
+                                       p->to.type = D_AX;
+                                       if(q1) {
+                                               q1->pcond = p;
+                                               q1 = P;
+                                       }
 
-                               p = appendp(p);
-                               p->as = ACALL;
-                               p->to.type = D_BRANCH;
-                               p->pcond = pmorestack;
-                               p->to.sym = symmorestack;
+                                       p = appendp(p);
+                                       p->as = ACALL;
+                                       p->to.type = D_BRANCH;
+                                       p->pcond = pmorestack10;
+                                       p->to.sym = symmorestack10;
+                               } else
+                               if(moreconst1 == 0 && moreconst2 != 0) {
+                                       p->as = AMOVL;
+                                       p->from.type = D_CONST;
+                                       p->from.offset = moreconst2;
+                                       p->to.type = D_AX;
+                                       if(q1) {
+                                               q1->pcond = p;
+                                               q1 = P;
+                                       }
+
+                                       p = appendp(p);
+                                       p->as = ACALL;
+                                       p->to.type = D_BRANCH;
+                                       p->pcond = pmorestack01;
+                                       p->to.sym = symmorestack01;
+                               } else {
 
+                                       p->as = AMOVQ;
+                                       p->from.type = D_CONST;
+                                       p->from.offset = (uint64)moreconst2 << 32;
+                                       p->from.offset |= moreconst1;
+                                       p->to.type = D_AX;
+                                       if(q1) {
+                                               q1->pcond = p;
+                                               q1 = P;
+                                       }
+
+                                       p = appendp(p);
+                                       p->as = ACALL;
+                                       p->to.type = D_BRANCH;
+                                       p->pcond = pmorestack11;
+                                       p->to.sym = symmorestack11;
+                               }
                        }
 
                        if(q != P)

diff --git a/src/runtime/amd64/asm.s b/src/runtime/amd64/asm.s
index 4557527b9ac6e5cb2feddb2d271e9fae614a9900..5efcac50e051098bad68e516ab490d7c228bc386 100644 (file)
--- a/src/runtime/amd64/asm.s
+++ b/src/runtime/amd64/asm.s
@@ -87,6 +87,30 @@ TEXT gosave(SB), 7, $0
  * support for morestack
  */
 
+// morestack trampolines
+TEXT   sys·morestack00+0(SB),7,$0
+       MOVQ    $0, AX
+       MOVQ    AX, 8(R14)
+       MOVQ    $sys·morestack+0(SB), AX
+       JMP     AX
+
+TEXT   sys·morestack01+0(SB),7,$0
+       SHLQ    $32, AX
+       MOVQ    AX, 8(R14)
+       MOVQ    $sys·morestack+0(SB), AX
+       JMP     AX
+
+TEXT   sys·morestack10+0(SB),7,$0
+       MOVLQZX AX, AX
+       MOVQ    AX, 8(R14)
+       MOVQ    $sys·morestack+0(SB), AX
+       JMP     AX
+
+TEXT   sys·morestack11+0(SB),7,$0
+       MOVQ    AX, 8(R14)
+       MOVQ    $sys·morestack+0(SB), AX
+       JMP     AX
+
 // return point when leaving new stack.  save AX, jmp to lessstack to switch back
 TEXT retfromnewstack(SB), 7, $0
        MOVQ    AX, 16(R14)     // save AX in m->cret