runtime: always use 1MB stacks on 32-bit Windows

Commit c2c07c7989 (CL 49331) changed the linker and runtime to always
use 2MB stacks on 64-bit Windows. This is the corresponding change to
make 32-bit Windows always use large (1MB) stacks because it's
difficult to detect when Windows applications will call into arbitrary
C code that may expect a large stack.

This is done as a separate change because it's possible this will
cause too much address space pressure for a 32-bit address space. On
the other hand, cgo binaries on Windows already use 1MB stacks and
there haven't been complaints.

Updates #20975.

Change-Id: I8ce583f07cb52254fb4bd47250f1ef2b789bc490
Reviewed-on: https://go-review.googlesource.com/49610
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go
index f48b35c6f99843fc95e9b7a632ac3b30fbac3459..8586c359adbb266f23e81f2370d7a1b13326728e 100644 (file)
--- a/src/cmd/link/internal/ld/pe.go
+++ b/src/cmd/link/internal/ld/pe.go
@@ -857,14 +857,10 @@ func (f *peFile) writeOptionalHeader(ctxt *Link) {
                oh64.SizeOfStackCommit = 0x00200000 - 0x2000 // account for 2 guard pages
        }
 
-       // 32-bit is trickier since there much less address space to
-       // work with. Here we use large stacks only in cgo binaries as
-       // a compromise.
+       oh.SizeOfStackReserve = 0x00100000
        if !iscgo {
-               oh.SizeOfStackReserve = 0x00020000
                oh.SizeOfStackCommit = 0x00001000
        } else {
-               oh.SizeOfStackReserve = 0x00100000
                oh.SizeOfStackCommit = 0x00100000 - 0x2000 // account for 2 guard pages
        }
 

diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go
index 025ff50a08129e262b30908d21dd83c1ede68eaf..7aeadd9ef1252f597c41ce5a5dcba88a44138178 100644 (file)
--- a/src/runtime/os_windows.go
+++ b/src/runtime/os_windows.go
@@ -623,7 +623,7 @@ func semacreate(mp *m) {
 func newosproc(mp *m, stk unsafe.Pointer) {
        const _STACK_SIZE_PARAM_IS_A_RESERVATION = 0x00010000
        // stackSize must match SizeOfStackReserve in cmd/link/internal/ld/pe.go.
-       const stackSize = 0x00200000*_64bit + 0x00020000*(1-_64bit)
+       const stackSize = 0x00200000*_64bit + 0x00100000*(1-_64bit)
        thandle := stdcall6(_CreateThread, 0, stackSize,
                funcPC(tstart_stdcall), uintptr(unsafe.Pointer(mp)),
                _STACK_SIZE_PARAM_IS_A_RESERVATION, 0)