runtime: record full frame size for arm _sfloat2

With preemption, _sfloat2 can show up in stack traces.
Write the function prototype in a way that accurately
shows the frame size and the fact that it might contain
pointers.

R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11523043

diff --git a/src/pkg/runtime/softfloat_arm.c b/src/pkg/runtime/softfloat_arm.c
index 56a73fce5c48e9d01598d03d46aaf61401d66b91..f021c929fffc739f64ea5f6405b262ea055ee2ec 100644 (file)
--- a/src/pkg/runtime/softfloat_arm.c
+++ b/src/pkg/runtime/softfloat_arm.c
@@ -576,23 +576,44 @@ done:
        return 0;
 }
 
-// The ... here is because there are actually 16 registers
-// being passed (r0, r1, and so on) amd we are too lazy
-// to list them all.
+typedef struct Sfregs Sfregs;
+
+// NOTE: These are all recorded as pointers because they are possibly live registers,
+// and we don't know what they contain. Recording them as pointers should be
+// safer than not.
+struct Sfregs
+{
+       uint32 *r0;
+       uint32 *r1;
+       uint32 *r2;
+       uint32 *r3;
+       uint32 *r4;
+       uint32 *r5;
+       uint32 *r6;
+       uint32 *r7;
+       uint32 *r8;
+       uint32 *r9;
+       uint32 *r10;
+       uint32 *r11;
+       uint32 *r12;
+       uint32 *r13;
+       uint32 cspr;
+};
+
 #pragma textflag 7
 uint32*
-runtime·_sfloat2(uint32 *lr, uint32 r0, ...)
+runtime·_sfloat2(uint32 *lr, Sfregs regs)
 {
        uint32 skip;
 
-       skip = stepflt(lr, &r0);
+       skip = stepflt(lr, (uint32*)&regs.r0);
        if(skip == 0) {
                runtime·printf("sfloat2 %p %x\n", lr, *lr);
                fabort(); // not ok to fail first instruction
        }
 
        lr += skip;
-       while(skip = stepflt(lr, &r0))
+       while(skip = stepflt(lr, (uint32*)&regs.r0))
                lr += skip;
        return lr;
 }