[PATCH] D100525: [Greedy RA] Add a check to MachineVerifier

Wed Apr 14 22:11:20 PDT 2021

skatkov created this revision.
skatkov added reviewers: reames, void, jyknight, nickdesaulniers, efriedma, arsenm.
Herald added subscribers: pengfei, jfb, hiraditya.
skatkov requested review of this revision.
Herald added a subscriber: wdng.
Herald added a project: LLVM.

If Virtual Register is alive in landing pad its def must be
before the call causing the exception or it should be statepoint instruction itself and
in this case def actually means the relocation of gc pointer and is alive in
landing pad.

The test shows the triggering this check for an option under development
use-registers-for-gc-values-in-landing-pad which is off by default until
it is functionally correct.


https://reviews.llvm.org/D100525

Files:
  llvm/lib/CodeGen/MachineVerifier.cpp
  llvm/test/CodeGen/X86/statepoint-invoke-ra1.ll


Index: llvm/test/CodeGen/X86/statepoint-invoke-ra1.ll
===================================================================

--- /dev/null
+++ llvm/test/CodeGen/X86/statepoint-invoke-ra1.ll
@@ -0,0 +1,63 @@
+; REQUIRES: asserts
+; RUN: not  --crash llc -o /dev/null %s -max-registers-for-gc-values=15 -use-registers-for-gc-values-in-landing-pad=true -verify-regalloc 2>&1 | FileCheck %s
+
+; The test checks the verification catch the case when RA splits live interval in the
+; way the def is located after invoke statepoint while use is in landing pad.
+
+; CHECK: *** Bad machine code: Register not marked live out of predecessor ***
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @wombat(i8 addrspace(1)* %arg, i32 %arg1, i32 addrspace(1)* %arg2) gc "statepoint-example" personality i32* ()* @widget {
+bb:
+  %tmp = load i8 addrspace(1)*, i8 addrspace(1)* addrspace(1)* null, align 8
+  %tmp3 = load i32, i32 addrspace(1)* null, align 4
+  %tmp4 = getelementptr inbounds i32, i32 addrspace(1)* %arg2, i64 24
+  %tmp5 = load i32, i32 addrspace(1)* %tmp4, align 4
+  %tmp6 = getelementptr inbounds i32, i32 addrspace(1)* %arg2, i64 40
+  %tmp7 = load i32, i32 addrspace(1)* %tmp6, align 4
+  %tmp8 = load i32, i32 addrspace(1)* null, align 4
+  %tmp9 = load i8 addrspace(1)*, i8 addrspace(1)* addrspace(1)* undef, align 8
+  %tmp10 = getelementptr inbounds i32, i32 addrspace(1)* %arg2, i64 88
+  %tmp11 = load i32, i32 addrspace(1)* %tmp10, align 4
+  %tmp12 = getelementptr inbounds i8, i8 addrspace(1)* %arg, i64 96
+  %tmp13 = bitcast i8 addrspace(1)* %tmp12 to i8 addrspace(1)* addrspace(1)*
+  %tmp14 = load i8 addrspace(1)*, i8 addrspace(1)* addrspace(1)* %tmp13, align 8
+  %tmp15 = getelementptr inbounds i8, i8 addrspace(1)* %arg, i64 104
+  %tmp16 = bitcast i8 addrspace(1)* %tmp15 to i8 addrspace(1)* addrspace(1)*
+  %tmp17 = load i8 addrspace(1)*, i8 addrspace(1)* addrspace(1)* %tmp16, align 8
+  %tmp18 = add i32 %tmp3, -1
+  %tmp19 = load atomic i64, i64 addrspace(1)* undef unordered, align 8
+  %tmp20 = invoke token (i64, i32, i32 (i32, i8 addrspace(1)*, i32, i32, i32)*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_i32i32p1i8i32i32i32f(i64 1, i32 16, i32 (i32, i8 addrspace(1)*, i32, i32, i32)* nonnull @wombat.1, i32 5, i32 0, i32 0, i8 addrspace(1)* null, i32 undef, i32 %arg1, i32 0, i32 0, i32 0) [ "deopt"(i32 %tmp18, i8 addrspace(1)* %tmp, i32 %arg1, i32 %tmp3, i32 %tmp5, i32 %tmp7, i32 %tmp8, i8 addrspace(1)* %tmp9, i32 %tmp11, i8 addrspace(1)* %tmp14, i8 addrspace(1)* %tmp17), "gc-live"(i8 addrspace(1)* %tmp, i8 addrspace(1)* %tmp9, i8 addrspace(1)* %tmp14, i8 addrspace(1)* %tmp17) ]
+          to label %bb21 unwind label %bb26
+
+bb21:                                             ; preds = %bb
+  %tmp22 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %tmp20, i32 0, i32 0) ; (%tmp, %tmp)
+  %tmp23 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %tmp20, i32 2, i32 2) ; (%tmp14, %tmp14)
+  %tmp24 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %tmp20, i32 3, i32 3) ; (%tmp17, %tmp17)
+  %tmp25 = call token (i64, i32, void (i32)*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidi32f(i64 2882400000, i32 0, void (i32)* nonnull @quux, i32 1, i32 2, i32 10, i32 0, i32 0) [ "deopt"(i32 %tmp18, i8 addrspace(1)* %tmp22, i32 %arg1, i32 %tmp3, i32 %tmp5, i32 %tmp7, i32 %tmp8, i32 %tmp11, i8 addrspace(1)* %tmp23, i8 addrspace(1)* %tmp24), "gc-live"() ]
+  ret void
+
+bb26:                                             ; preds = %bb
+  %tmp27 = landingpad token
+          cleanup
+  %tmp28 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token %tmp27, i32 1, i32 1) ; (%tmp9, %tmp9)
+  %tmp29 = call token (i64, i32, void (i32)*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidi32f(i64 2882400000, i32 0, void (i32)* nonnull @quux, i32 1, i32 0, i32 -271, i32 0, i32 0) [ "deopt"(i32 %arg1, i32 %tmp3, i32 %tmp5, i32 %tmp8, i8 addrspace(1)* %tmp28, i32 %tmp11), "gc-live"() ]
+  unreachable
+}
+
+declare i32* @widget()
+
+declare i32 @wombat.1(i32, i8 addrspace(1)*, i32, i32, i32)
+
+declare void @quux(i32)
+
+declare token @llvm.experimental.gc.statepoint.p0f_isVoidi32f(i64 immarg, i32 immarg, void (i32)*, i32 immarg, i32 immarg, ...)
+
+; Function Attrs: nounwind readonly
+declare i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token, i32 immarg, i32 immarg) #0
+
+declare token @llvm.experimental.gc.statepoint.p0f_i32i32p1i8i32i32i32f(i64 immarg, i32 immarg, i32 (i32, i8 addrspace(1)*, i32, i32, i32)*, i32 immarg, i32 immarg, ...)
+
+attributes #0 = { nounwind readonly }
Index: llvm/lib/CodeGen/MachineVerifier.cpp
===================================================================
--- llvm/lib/CodeGen/MachineVerifier.cpp
+++ llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2972,6 +2972,15 @@
     // Check that VNI is live-out of all predecessors.
     for (const MachineBasicBlock *Pred : MFI->predecessors()) {
       SlotIndex PEnd = LiveInts->getMBBEndIdx(Pred);
+      // Predecessor of landing pad live-out on last call.
+      // If last call is a statepoint and has tied-def it is
+      // relocated gc pointer and its value is alive in landing pad.
+      if (MFI->isEHPad())
+        for (auto I = Pred->rbegin(), E = Pred->rend(); I != E; ++I)
+          if (I->isCall()) {
+            PEnd = Indexes->getInstructionIndex(*I).getBoundaryIndex();
+            break;
+          }
       const VNInfo *PVNI = LR.getVNInfoBefore(PEnd);
 
       // All predecessors must have a live-out value. However for a phi


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