diff options
Diffstat (limited to 'src/runtime/mranges.go')
| -rw-r--r-- | src/runtime/mranges.go | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/src/runtime/mranges.go b/src/runtime/mranges.go index 468a73057b..e574c2f518 100644 --- a/src/runtime/mranges.go +++ b/src/runtime/mranges.go @@ -69,6 +69,31 @@ func (a addrRange) subtract(b addrRange) addrRange { return a } +var ( + // minOffAddr is the minimum address in the offset space, and + // it corresponds to the virtual address -arenaBaseOffset. + // + // We don't initialize this with offAddrFromRaw because allocation + // may happen during bootstrapping, and we rely on this value + // being initialized. + // + // As a result, creating this value in Go is tricky because of + // overflow not being allowed in constants. In order to get + // the value we want, we take arenaBaseOffset and do a manual + // two's complement negation, then mask that into what can fit + // into a uintptr. + minOffAddr = offAddr{((^arenaBaseOffset) + 1) & uintptrMask} + + // maxOffAddr is the maximum address in the offset address + // space, and it corresponds to the virtual address + // ^uintptr(0) - arenaBaseOffset. + // + // We don't initialize this with offAddrFromRaw because allocation + // may happen during bootstrapping, and we rely on this value + // being initialized. + maxOffAddr = offAddr{^uintptr(0) - arenaBaseOffset} +) + // offAddr represents an address in a contiguous view // of the address space on systems where the address space is // segmented. On other systems, it's just a normal address. @@ -268,7 +293,7 @@ func (a *addrRanges) removeGreaterEqual(addr uintptr) { } if r := a.ranges[pivot-1]; r.contains(addr) { removed += r.size() - r = r.subtract(makeAddrRange(addr, maxSearchAddr)) + r = r.subtract(makeAddrRange(addr, maxOffAddr.addr())) if r.size() == 0 { pivot-- } else { |