diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86FrameLowering.cpp | 18 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/x86-shrink-wrap-unwind.ll | 83 |
2 files changed, 94 insertions, 7 deletions
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index 8f21fb49728..a6d395b92a0 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -2030,6 +2030,10 @@ void X86FrameLowering::adjustForSegmentedStacks( unsigned TlsReg, TlsOffset; DebugLoc DL; + // To support shrink-wrapping we would need to insert the new blocks + // at the right place and update the branches to PrologueMBB. + assert(&(*MF.begin()) == &PrologueMBB && "Shrink-wrapping not supported yet"); + unsigned ScratchReg = GetScratchRegister(Is64Bit, IsLP64, MF, true); assert(!MF.getRegInfo().isLiveIn(ScratchReg) && "Scratch register is live-in"); @@ -2270,6 +2274,11 @@ void X86FrameLowering::adjustForHiPEPrologue( MachineFunction &MF, MachineBasicBlock &PrologueMBB) const { MachineFrameInfo *MFI = MF.getFrameInfo(); DebugLoc DL; + + // To support shrink-wrapping we would need to insert the new blocks + // at the right place and update the branches to PrologueMBB. + assert(&(*MF.begin()) == &PrologueMBB && "Shrink-wrapping not supported yet"); + // HiPE-specific values const unsigned HipeLeafWords = 24; const unsigned CCRegisteredArgs = Is64Bit ? 6 : 5; @@ -2583,7 +2592,14 @@ bool X86FrameLowering::canUseAsEpilogue(const MachineBasicBlock &MBB) const { bool X86FrameLowering::enableShrinkWrapping(const MachineFunction &MF) const { // If we may need to emit frameless compact unwind information, give // up as this is currently broken: PR25614. - return MF.getFunction()->hasFnAttribute(Attribute::NoUnwind) || hasFP(MF); + return (MF.getFunction()->hasFnAttribute(Attribute::NoUnwind) || hasFP(MF)) && + // The lowering of segmented stack and HiPE only support entry blocks + // as prologue blocks: PR26107. + // This limitation may be lifted if we fix: + // - adjustForSegmentedStacks + // - adjustForHiPEPrologue + MF.getFunction()->getCallingConv() != CallingConv::HiPE && + !MF.shouldSplitStack(); } MachineBasicBlock::iterator X86FrameLowering::restoreWin32EHStackPointers( diff --git a/llvm/test/CodeGen/X86/x86-shrink-wrap-unwind.ll b/llvm/test/CodeGen/X86/x86-shrink-wrap-unwind.ll index 7c00f407b1e..eb87f7101d7 100644 --- a/llvm/test/CodeGen/X86/x86-shrink-wrap-unwind.ll +++ b/llvm/test/CodeGen/X86/x86-shrink-wrap-unwind.ll @@ -1,11 +1,5 @@ ; RUN: llc %s -o - | FileCheck %s --check-prefix=CHECK ; -; This test checks that we do not use shrink-wrapping when -; the function does not have any frame pointer and may unwind. -; This is a workaround for a limitation in the emission of -; the CFI directives, that are not correct in such case. -; PR25614 -; ; Note: This test cannot be merged with the shrink-wrapping tests ; because the booleans set on the command line take precedence on ; the target logic that disable shrink-wrapping. @@ -13,6 +7,12 @@ target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128" target triple = "x86_64-apple-macosx" +; This test checks that we do not use shrink-wrapping when +; the function does not have any frame pointer and may unwind. +; This is a workaround for a limitation in the emission of +; the CFI directives, that are not correct in such case. +; PR25614 +; ; No shrink-wrapping should occur here, until the CFI information are fixed. ; CHECK-LABEL: framelessUnwind: ; @@ -151,3 +151,74 @@ false: } attributes #2 = { "no-frame-pointer-elim"="false" nounwind } + + +; Check that we generate correct code for segmented stack. +; We used to emit the code at the entry point of the function +; instead of just before the prologue. +; For now, shrink-wrapping is disabled on segmented stack functions: PR26107. +; +; CHECK-LABEL: segmentedStack: +; CHECK: cmpq +; CHECK-NEXT: ja [[ENTRY_LABEL:LBB[0-9_]+]] +; +; CHECK: callq ___morestack +; CHECK-NEXT: retq +; +; CHECK: [[ENTRY_LABEL]]: +; Prologue +; CHECK: push +; +; In PR26107, we use to drop these two basic blocks, because +; the segmentedStack entry block was jumping directly to +; the place where the prologue is actually needed, which is +; the call to memcmp. +; Then, those two basic blocks did not have any predecessors +; anymore and were removed. +; +; Check if vk1 is null +; CHECK: testq %rdi, %rdi +; CHECK-NEXT: je [[STRINGS_EQUAL:LBB[0-9_]+]] +; +; Check if vk2 is null +; CHECK: testq %rsi, %rsi +; CHECK-NEXT: je [[STRINGS_EQUAL]] +; +; CHECK: [[STRINGS_EQUAL]] +; CHECK-NEXT: popq +define zeroext i1 @segmentedStack(i8* readonly %vk1, i8* readonly %vk2, i64 %key_size) #5 { +entry: + %cmp.i = icmp eq i8* %vk1, null + %cmp1.i = icmp eq i8* %vk2, null + %brmerge.i = or i1 %cmp.i, %cmp1.i + %cmp1.mux.i = and i1 %cmp.i, %cmp1.i + br i1 %brmerge.i, label %__go_ptr_strings_equal.exit, label %if.end4.i + +if.end4.i: ; preds = %entry + %tmp = getelementptr inbounds i8, i8* %vk1, i64 8 + %tmp1 = bitcast i8* %tmp to i64* + %tmp2 = load i64, i64* %tmp1, align 8 + %tmp3 = getelementptr inbounds i8, i8* %vk2, i64 8 + %tmp4 = bitcast i8* %tmp3 to i64* + %tmp5 = load i64, i64* %tmp4, align 8 + %cmp.i.i = icmp eq i64 %tmp2, %tmp5 + br i1 %cmp.i.i, label %land.rhs.i.i, label %__go_ptr_strings_equal.exit + +land.rhs.i.i: ; preds = %if.end4.i + %tmp6 = bitcast i8* %vk2 to i8** + %tmp7 = load i8*, i8** %tmp6, align 8 + %tmp8 = bitcast i8* %vk1 to i8** + %tmp9 = load i8*, i8** %tmp8, align 8 + %call.i.i = tail call i32 @memcmp(i8* %tmp9, i8* %tmp7, i64 %tmp2) #5 + %cmp4.i.i = icmp eq i32 %call.i.i, 0 + br label %__go_ptr_strings_equal.exit + +__go_ptr_strings_equal.exit: ; preds = %land.rhs.i.i, %if.end4.i, %entry + %retval.0.i = phi i1 [ %cmp1.mux.i, %entry ], [ false, %if.end4.i ], [ %cmp4.i.i, %land.rhs.i.i ] + ret i1 %retval.0.i +} + +; Function Attrs: nounwind readonly +declare i32 @memcmp(i8* nocapture, i8* nocapture, i64) #5 + +attributes #5 = { nounwind readonly ssp uwtable "split-stack" } |
