From 5a96b41c7098411204a186712ff3aa988a2c8913 Mon Sep 17 00:00:00 2001 From: Philip Reames Date: Fri, 1 Aug 2014 18:26:27 +0000 Subject: [PATCH] Explicitly report runtime stack realignment in StackMap section This change adds code to explicitly mark a function which requires runtime stack realignment as not having a fixed frame size in the StackMap section. As it happens, this is not actually a functional change. The size that would be reported without the check is also "-1", but as far as I can tell, that's an accident. The code change makes this explicit. Note: There's a separate bug in handling of stackmaps and patchpoints in functions which need dynamic frame realignment. The current code assumes that offsets can be calculated from RBP, but realigned frames must use RSP. (There's a variable gap between RBP and the spill slots.) This change set does not address that issue. Reviewers: atrick, ributzka Differential Revision: http://reviews.llvm.org/D4572 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214534 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/StackMaps.cpp | 5 ++++- test/CodeGen/X86/stackmap.ll | 23 +++++++++++++++++++++-- 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/lib/CodeGen/StackMaps.cpp b/lib/CodeGen/StackMaps.cpp index 1473fc184f8..6c7547fe2b2 100644 --- a/lib/CodeGen/StackMaps.cpp +++ b/lib/CodeGen/StackMaps.cpp @@ -236,8 +236,11 @@ void StackMaps::recordStackMapOpers(const MachineInstr &MI, uint64_t ID, // Record the stack size of the current function. const MachineFrameInfo *MFI = AP.MF->getFrameInfo(); + const TargetRegisterInfo *RegInfo = AP.MF->getTarget().getRegisterInfo(); + const bool DynamicFrameSize = MFI->hasVarSizedObjects() || + RegInfo->needsStackRealignment(*(AP.MF)); FnStackSize[AP.CurrentFnSym] = - MFI->hasVarSizedObjects() ? UINT64_MAX : MFI->getStackSize(); + DynamicFrameSize ? UINT64_MAX : MFI->getStackSize(); } void StackMaps::recordStackMap(const MachineInstr &MI) { diff --git a/test/CodeGen/X86/stackmap.ll b/test/CodeGen/X86/stackmap.ll index 85670370d87..3e87ee114ba 100644 --- a/test/CodeGen/X86/stackmap.ll +++ b/test/CodeGen/X86/stackmap.ll @@ -9,11 +9,11 @@ ; CHECK-NEXT: .byte 0 ; CHECK-NEXT: .short 0 ; Num Functions -; CHECK-NEXT: .long 15 +; CHECK-NEXT: .long 16 ; Num LargeConstants ; CHECK-NEXT: .long 3 ; Num Callsites -; CHECK-NEXT: .long 19 +; CHECK-NEXT: .long 20 ; Functions and stack size ; CHECK-NEXT: .quad _constantargs @@ -46,6 +46,8 @@ ; CHECK-NEXT: .quad 8 ; CHECK-NEXT: .quad _clobberScratch ; CHECK-NEXT: .quad 56 +; CHECK-NEXT: .quad _needsStackRealignment +; CHECK-NEXT: .quad -1 ; Large Constants ; CHECK-NEXT: .quad 2147483648 @@ -464,6 +466,23 @@ define void @clobberScratch(i32 %a) { ret void } +; A stack frame which needs to be realigned at runtime (to meet alignment +; criteria for values on the stack) does not have a fixed frame size. +; CHECK-LABEL: .long L{{.*}}-_needsStackRealignment +; CHECK-NEXT: .short 0 +; 0 locations +; CHECK-NEXT: .short 0 +define void @needsStackRealignment() { + %val = alloca i64, i32 3, align 128 + tail call void (...)* @escape_values(i64* %val) +; Note: Adding any non-constant to the stackmap would fail because we +; expected to be able to address off the frame pointer. In a realigned +; frame, we must use the stack pointer instead. This is a separate bug. + tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 0) + ret void +} +declare void @escape_values(...) + declare void @llvm.experimental.stackmap(i64, i32, ...) declare void @llvm.experimental.patchpoint.void(i64, i32, i8*, i32, ...) declare i64 @llvm.experimental.patchpoint.i64(i64, i32, i8*, i32, ...) -- 2.34.1