#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/CommandLine.h"
using namespace llvm;
+static cl::opt<bool>
+ForceStackAlign("force-align-stack",
+ cl::desc("Force align the stack to the minimum alignment"
+ " needed for the function."),
+ cl::init(false), cl::Hidden);
+
X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
const TargetInstrInfo &tii)
: X86GenRegisterInfo(tm.getSubtarget<X86Subtarget>().is64Bit() ?
if (0 && requiresRealignment && MFI->hasVarSizedObjects())
report_fatal_error(
"Stack realignment in presense of dynamic allocas is not supported");
-
+
+ // If we've requested that we force align the stack do so now.
+ if (ForceStackAlign)
+ return canRealignStack(MF);
+
return requiresRealignment && canRealignStack(MF);
}
bool HasFP = hasFP(MF);
DebugLoc DL;
+ // If we're forcing a stack realignment we can't rely on just the frame
+ // info, we need to know the ABI stack alignment as well in case we
+ // have a call out. Otherwise just make sure we have some alignment - we'll
+ // go with the minimum SlotSize.
+ if (ForceStackAlign) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else if (MaxAlign < SlotSize)
+ MaxAlign = SlotSize;
+ }
+
// Add RETADDR move area to callee saved frame size.
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t NumBytes = 0;
+ // If we're forcing a stack realignment we can't rely on just the frame
+ // info, we need to know the ABI stack alignment as well in case we
+ // have a call out. Otherwise just make sure we have some alignment - we'll
+ // go with the minimum.
+ if (ForceStackAlign) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else
+ MaxAlign = MaxAlign ? MaxAlign : 4;
+ }
+
if (hasFP(MF)) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
--- /dev/null
+; RUN: llc < %s -relocation-model=static -force-align-stack | FileCheck %s
+; Tests to make sure that we always align the stack out to the minimum needed -
+; in this case 16-bytes.
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
+target triple = "i386-apple-darwin10.3"
+
+define void @a() nounwind ssp {
+entry:
+; CHECK: _a:
+; CHECK: andl $-16, %esp
+ %z = alloca <16 x i8> ; <<16 x i8>*> [#uses=2]
+ %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
+ store <16 x i8> zeroinitializer, <16 x i8>* %z, align 16
+ call void @b(<16 x i8>* %z) nounwind
+ br label %return
+
+return: ; preds = %entry
+ ret void
+}
+
+declare void @b(<16 x i8>*)