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runtime: fix -d=checkptr failure for testing/quick

This CL extends checkptrBase to recognize pointers into the stack and
data/bss sections. I was meaning to do this eventually anyway, but
it's also an easy way to workaround #35068.

Updates #35068.

Change-Id: Ib47f0aa800473a4fbc249da52ff03bec32c3ebe2
Reviewed-on: https://go-review.googlesource.com/c/go/+/202639
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Matthew Dempsky 2019-10-22 11:59:00 -07:00
parent 7d84245a9c
commit 5a5854c2d1

View File

@ -64,9 +64,41 @@ func checkptrArithmetic(p unsafe.Pointer, originals []unsafe.Pointer) {
panic(ptrArithError{p, originals})
}
// checkptrBase returns the base address for the allocation containing
// the address p.
//
// Importantly, if p1 and p2 point into the same variable, then
// checkptrBase(p1) == checkptrBase(p2). However, the converse/inverse
// is not necessarily true as allocations can have trailing padding,
// and multiple variables may be packed into a single allocation.
func checkptrBase(p unsafe.Pointer) uintptr {
base, _, _ := findObject(uintptr(p), 0, 0)
// TODO(mdempsky): If base == 0, then check if p points to the
// stack or a global variable.
// stack
if gp := getg(); gp.stack.lo <= uintptr(p) && uintptr(p) < gp.stack.hi {
// TODO(mdempsky): Walk the stack to identify the
// specific stack frame or even stack object that p
// points into.
//
// In the mean time, use "1" as a pseudo-address to
// represent the stack. This is an invalid address on
// all platforms, so it's guaranteed to be distinct
// from any of the addresses we might return below.
return 1
}
// heap (must check after stack because of #35068)
if base, _, _ := findObject(uintptr(p), 0, 0); base != 0 {
return base
}
// data or bss
for _, datap := range activeModules() {
if datap.data <= uintptr(p) && uintptr(p) < datap.edata {
return datap.data
}
if datap.bss <= uintptr(p) && uintptr(p) < datap.ebss {
return datap.bss
}
}
return 0
}