diff options
Diffstat (limited to 'src/cmd/6l/pass.c')
| -rw-r--r-- | src/cmd/6l/pass.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c index 2357a7f77..c9b477627 100644 --- a/src/cmd/6l/pass.c +++ b/src/cmd/6l/pass.c @@ -501,10 +501,17 @@ dostkoff(void) q = p; } - /* 160 comes from 3 calls (3*8) 4 safes (4*8) and 104 guard */ + // If we ask for more stack, we'll get a minimum of StackMin bytes. + // We need a stack frame large enough to hold the top-of-stack data, + // the function arguments+results, our caller's PC, our frame, + // a word for the return PC of the next call, and then the StackLimit bytes + // that must be available on entry to any function called from a function + // that did a stack check. If StackMin is enough, don't ask for a specific + // amount: then we can use the custom functions and save a few + // instructions. moreconst1 = 0; - if(autoffset+160+textarg > 4096) - moreconst1 = (autoffset+160) & ~7LL; + if(StackTop + textarg + PtrSize + autoffset + PtrSize + StackLimit >= StackMin) + moreconst1 = autoffset; moreconst2 = textarg; // 4 varieties varieties (const1==0 cross const2==0) |