[llvm-branch-commits] [llvm] f744390 - [Statepoint] Handle `undef` operands in statepoint.

Denis Antrushin via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Mon Jan 18 04:26:53 PST 2021


Author: Denis Antrushin
Date: 2021-01-18T15:20:54+03:00
New Revision: f7443905af1e06eaacda1e437fff8d54dc89c487

URL: https://github.com/llvm/llvm-project/commit/f7443905af1e06eaacda1e437fff8d54dc89c487
DIFF: https://github.com/llvm/llvm-project/commit/f7443905af1e06eaacda1e437fff8d54dc89c487.diff

LOG: [Statepoint] Handle `undef` operands in statepoint.

Currently when spilling statepoint register operands in FixupStatepoints
we do not pay attention that it might be `undef`. We just generate a
spill, which may lead to verifier error because we have a use without def.

To handle it, let FixupStateponts ignore `undef` register operands
completely and change them to some constant value when generating
stack map. Use same value as used by ISel for this purpose (0xFEFEFEFE).

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D94703

Added: 
    llvm/test/CodeGen/X86/statepoint-fixup-undef.mir

Modified: 
    llvm/lib/CodeGen/FixupStatepointCallerSaved.cpp
    llvm/lib/CodeGen/StackMaps.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/FixupStatepointCallerSaved.cpp b/llvm/lib/CodeGen/FixupStatepointCallerSaved.cpp
index 662bd1a3646f..f8f99b7e87f2 100644
--- a/llvm/lib/CodeGen/FixupStatepointCallerSaved.cpp
+++ b/llvm/lib/CodeGen/FixupStatepointCallerSaved.cpp
@@ -380,7 +380,9 @@ class StatepointState {
                   EndIdx = MI.getNumOperands();
          Idx < EndIdx; ++Idx) {
       MachineOperand &MO = MI.getOperand(Idx);
-      if (!MO.isReg() || MO.isImplicit())
+      // Leave `undef` operands as is, StackMaps will rewrite them
+      // into a constant.
+      if (!MO.isReg() || MO.isImplicit() || MO.isUndef())
         continue;
       Register Reg = MO.getReg();
       assert(Reg.isPhysical() && "Only physical regs are expected");

diff  --git a/llvm/lib/CodeGen/StackMaps.cpp b/llvm/lib/CodeGen/StackMaps.cpp
index 220e85fe90dc..faf07e90c39c 100644
--- a/llvm/lib/CodeGen/StackMaps.cpp
+++ b/llvm/lib/CodeGen/StackMaps.cpp
@@ -234,6 +234,12 @@ StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
     if (MOI->isImplicit())
       return ++MOI;
 
+    if (MOI->isUndef()) {
+      // Record `undef` register as constant. Use same value as ISel uses.
+      Locs.emplace_back(Location::Constant, sizeof(int64_t), 0, 0xFEFEFEFE);
+      return ++MOI;
+    }
+
     assert(Register::isPhysicalRegister(MOI->getReg()) &&
            "Virtreg operands should have been rewritten before now.");
     const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(MOI->getReg());

diff  --git a/llvm/test/CodeGen/X86/statepoint-fixup-undef.mir b/llvm/test/CodeGen/X86/statepoint-fixup-undef.mir
new file mode 100644
index 000000000000..434c8400316d
--- /dev/null
+++ b/llvm/test/CodeGen/X86/statepoint-fixup-undef.mir
@@ -0,0 +1,234 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -x mir -run-pass fixup-statepoint-caller-saved -verify-machineinstrs < %s | FileCheck %s
+# RUN: llc -x mir -start-before fixup-statepoint-caller-saved -verify-machineinstrs < %s | FileCheck %s -check-prefix=STACKMAP
+
+--- |
+  ; ModuleID = 'undef.ll'
+  source_filename = "test_undef.ll"
+  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+
+  define void @test_undef(i8 addrspace(1)* %arg1, i8 addrspace(1)* %arg2, i8 addrspace(1)* %arg3, i8 addrspace(1)* %arg4) #0 gc "statepoint-example" {
+  bb:
+    %tmp1 = lshr i32 0, undef
+    %tmp2 = load atomic i32, i32 addrspace(1)* undef unordered, align 8
+    %tmp3 = load atomic i32, i32 addrspace(1)* undef unordered, align 8
+    br label %bb7
+
+  bb7:                                              ; preds = %bb
+    %tmp4 = icmp slt i32 %tmp3, undef
+    %tmp5 = select i1 %tmp4, i32 6, i32 undef
+    %tmp6 = add i32 %tmp5, %tmp2
+    %tmp7 = call i8 addrspace(1)* @wombat()
+    %tmp20 = call token (i64, i32, void (i8 addrspace(1)*, i32, i32, i8 addrspace(1)*, i32)*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidp1i8i32i32p1i8i32f(i64 2, i32 5, void (i8 addrspace(1)*, i32, i32, i8 addrspace(1)*, i32)* nonnull @hoge, i32 5, i32 0, i8 addrspace(1)* %arg3, i32 %tmp2, i32 %tmp6, i8 addrspace(1)* %tmp7, i32 0, i32 0, i32 0) [ "deopt"(i8 addrspace(1)* %arg2, i8 addrspace(1)* %arg1, i8 addrspace(1)* %arg3, i8 addrspace(1)* %arg4, i32 %tmp2, i32 %tmp1, i32 %tmp5), "gc-live"() ]
+    ret void
+  }
+
+  declare void @hoge(i8 addrspace(1)*, i32, i32, i8 addrspace(1)*, i32) #0
+
+  declare i8 addrspace(1)* @wombat() #0
+
+  ; Function Attrs: nounwind readonly
+  declare i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token, i32 immarg, i32 immarg) #1
+
+  declare token @llvm.experimental.gc.statepoint.p0f_isVoidp1i8i32i32p1i8i32f(i64 immarg, i32 immarg, void (i8 addrspace(1)*, i32, i32, i8 addrspace(1)*, i32)*, i32 immarg, i32 immarg, ...) #0
+
+  attributes #0 = { "target-cpu"="broadwell" }
+  attributes #1 = { nounwind readonly "target-cpu"="broadwell" }
+
+...
+---
+name:            test_undef
+alignment:       16
+exposesReturnsTwice: false
+legalized:       false
+regBankSelected: false
+selected:        false
+failedISel:      false
+tracksRegLiveness: true
+hasWinCFI:       false
+registers:       []
+liveins:
+  - { reg: '$rdi', virtual-reg: '' }
+  - { reg: '$rsi', virtual-reg: '' }
+  - { reg: '$rdx', virtual-reg: '' }
+  - { reg: '$rcx', virtual-reg: '' }
+frameInfo:
+  isFrameAddressTaken: false
+  isReturnAddressTaken: false
+  hasStackMap:     false
+  hasPatchPoint:   false
+  stackSize:       0
+  offsetAdjustment: 0
+  maxAlignment:    8
+  adjustsStack:    false
+  hasCalls:        true
+  stackProtector:  ''
+  maxCallFrameSize: 4294967295
+  cvBytesOfCalleeSavedRegisters: 0
+  hasOpaqueSPAdjustment: false
+  hasVAStart:      false
+  hasMustTailInVarArgFunc: false
+  localFrameSize:  0
+  savePoint:       ''
+  restorePoint:    ''
+fixedStack:      []
+stack:
+  - { id: 0, name: '', type: default, offset: 0, size: 8, alignment: 8,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, name: '', type: default, offset: 0, size: 8, alignment: 8,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 2, name: '', type: default, offset: 0, size: 8, alignment: 8,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 3, name: '', type: default, offset: 0, size: 8, alignment: 8,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+callSites:       []
+debugValueSubstitutions: []
+constants:       []
+machineFunctionInfo: {}
+body:             |
+  ; CHECK-LABEL: name: test_undef
+  ; CHECK: bb.0.bb:
+  ; CHECK:   successors: %bb.1(0x80000000)
+  ; CHECK:   liveins: $rcx, $rdi, $rdx, $rsi
+  ; CHECK:   renamable $r15 = COPY $rcx
+  ; CHECK:   renamable $r14 = COPY $rdx
+  ; CHECK:   renamable $r13 = COPY $rsi
+  ; CHECK:   renamable $r12 = COPY $rdi
+  ; CHECK:   renamable $ebx = MOV32rm undef renamable $rax, 1, $noreg, 0, $noreg, implicit-def $rbx :: (load unordered 4 from `i32 addrspace(1)* undef`, align 8, addrspace 1)
+  ; CHECK: bb.1.bb7:
+  ; CHECK:   liveins: $rbx, $r12, $r13, $r14, $r15
+  ; CHECK:   renamable $ebp = LEA64_32r renamable $rbx, 1, $noreg, 6, $noreg
+  ; CHECK:   ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+  ; CHECK:   CALL64pcrel32 target-flags(x86-plt) @wombat, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
+  ; CHECK:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+  ; CHECK:   MOV64mr %stack.0, 1, $noreg, 0, $noreg, killed renamable $r13 :: (store 8 into %stack.0)
+  ; CHECK:   MOV64mr %stack.1, 1, $noreg, 0, $noreg, killed renamable $r12 :: (store 8 into %stack.1)
+  ; CHECK:   MOV64mr %stack.2, 1, $noreg, 0, $noreg, renamable $r14 :: (store 8 into %stack.2)
+  ; CHECK:   MOV64mr %stack.3, 1, $noreg, 0, $noreg, killed renamable $r15 :: (store 8 into %stack.3)
+  ; CHECK:   ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+  ; CHECK:   $rdi = COPY killed renamable $r14
+  ; CHECK:   $esi = COPY renamable $ebx
+  ; CHECK:   $edx = COPY killed renamable $ebp
+  ; CHECK:   $rcx = COPY killed renamable $rax
+  ; CHECK:   $r8d = MOV32r0 implicit-def dead $eflags
+  ; CHECK:   STATEPOINT 2, 5, 5, undef renamable $rax, $rdi, $esi, $edx, $rcx, killed $r8d, 2, 0, 2, 0, 2, 7, 1, 8, %stack.0, 0, 1, 8, %stack.1, 0, 1, 8, %stack.2, 0, 1, 8, %stack.3, 0, renamable $ebx, undef renamable $eax, 2, 6, 2, 0, 2, 0, 2, 0, csr_64, implicit-def $rsp, implicit-def $ssp, implicit killed $rbx :: (volatile load store 8 on %stack.0), (volatile load store 8 on %stack.1), (volatile load store 8 on %stack.2), (volatile load store 8 on %stack.3)
+  ; CHECK:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+  ; CHECK:   RET 0
+  ; STACKMAP-LABEL: __LLVM_StackMaps:
+  ; STACKMAP:	.byte	3
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	1
+  ; STACKMAP:	.long	1
+  ; STACKMAP:	.long	1
+  ; STACKMAP:	.quad	test_undef
+  ; STACKMAP:	.quad	88
+  ; STACKMAP:	.quad	1
+  ; STACKMAP:	.quad	4278124286
+  ; STACKMAP:	.quad	2
+  ; STACKMAP:	.long	.Ltmp0-test_undef
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	10
+  ; STACKMAP:	.byte	4
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	0
+  ; STACKMAP:	.byte	4
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	0
+  ; STACKMAP:	.byte	4
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	7
+  ; STACKMAP:	.byte	3
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	7
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	32
+  ; STACKMAP:	.byte	3
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	7
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	24
+  ; STACKMAP:	.byte	3
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	7
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	16
+  ; STACKMAP:	.byte	3
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	7
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	8
+  ; STACKMAP:	.byte	1
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	4
+  ; STACKMAP:	.short	3
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	0
+  ;      This is entry we're looking for, reference to constant pool entry 0xFEFEFEFE
+  ; STACKMAP:	.byte	5
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	0
+  ; STACKMAP:	.byte	4
+  ; STACKMAP:	.byte	0
+  ; STACKMAP:	.short	8
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.long	6
+  ; STACKMAP:	.p2align	3
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.short	0
+  ; STACKMAP:	.p2align	3
+  bb.0.bb:
+    successors: %bb.1(0x80000000)
+    liveins: $rcx, $rdi, $rdx, $rsi
+
+    renamable $r15 = COPY $rcx
+    renamable $r14 = COPY $rdx
+    renamable $r13 = COPY $rsi
+    renamable $r12 = COPY $rdi
+    renamable $ebx = MOV32rm undef renamable $rax, 1, $noreg, 0, $noreg, implicit-def $rbx :: (load unordered 4 from `i32 addrspace(1)* undef`, align 8, addrspace 1)
+
+  bb.1.bb7:
+    liveins: $rbx, $r12, $r13, $r14, $r15
+
+    renamable $ebp = LEA64_32r renamable $rbx, 1, $noreg, 6, $noreg
+    ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+    CALL64pcrel32 target-flags(x86-plt) @wombat, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $rax
+    ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+    MOV64mr %stack.0, 1, $noreg, 0, $noreg, killed renamable $r13 :: (store 8 into %stack.0)
+    MOV64mr %stack.1, 1, $noreg, 0, $noreg, killed renamable $r12 :: (store 8 into %stack.1)
+    MOV64mr %stack.2, 1, $noreg, 0, $noreg, renamable $r14 :: (store 8 into %stack.2)
+    MOV64mr %stack.3, 1, $noreg, 0, $noreg, killed renamable $r15 :: (store 8 into %stack.3)
+    ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+    $rdi = COPY killed renamable $r14
+    $esi = COPY renamable $ebx
+    $edx = COPY killed renamable $ebp
+    $rcx = COPY killed renamable $rax
+    $r8d = MOV32r0 implicit-def dead $eflags
+    STATEPOINT 2, 5, 5, undef renamable $rax, $rdi, $esi, $edx, $rcx, killed $r8d, 2, 0, 2, 0, 2, 7, 1, 8, %stack.0, 0, 1, 8, %stack.1, 0, 1, 8, %stack.2, 0, 1, 8, %stack.3, 0, renamable $ebx, undef renamable $eax, 2, 6, 2, 0, 2, 0, 2, 0, csr_64, implicit-def $rsp, implicit-def $ssp, implicit killed $rbx :: (volatile load store 8 on %stack.0), (volatile load store 8 on %stack.1), (volatile load store 8 on %stack.2), (volatile load store 8 on %stack.3)
+    ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
+    RET 0
+
+...
+


        


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