[CFIInstrInserter] Tests for scenarios not currently handled by CFIInstrInserter.

llvm/lib/Target/RISCV/RISCVFrameLowering.cpp

@@ -2239,3 +2239,12 @@ void RISCVFrameLowering::inlineStackProbe(MachineFunction &MF,
     }
   }
 }
+
+int RISCVFrameLowering::getInitialCFAOffset(const MachineFunction &MF) const {
+  return 0;
+}
+
+Register
+RISCVFrameLowering::getInitialCFARegister(const MachineFunction &MF) const {
+  return RISCV::X2;
+}

llvm/lib/Target/RISCV/RISCVFrameLowering.h

@@ -112,6 +112,8 @@ class RISCVFrameLowering : public TargetFrameLowering {
                                    const DebugLoc &DL, int64_t Amount,
                                    MachineInstr::MIFlag Flag, bool EmitCFI,
                                    bool DynAllocation) const;
+  int getInitialCFAOffset(const MachineFunction &MF) const override;
+  Register getInitialCFARegister(const MachineFunction &MF) const override;
 };
 } // namespace llvm
 #endif

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -117,6 +117,11 @@ static cl::opt<bool>
                            cl::desc("Enable Machine Pipeliner for RISC-V"),
                            cl::init(false), cl::Hidden);
 
+static cl::opt<bool> EnableCFIInstrInserter(
+    "riscv-enable-cfi-instr-inserter",
+    cl::desc("Enable CFI Instruction Inserter for RISC-V"), cl::init(false),
+    cl::Hidden);
+
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeRISCVTarget() {
   RegisterTargetMachine<RISCVTargetMachine> X(getTheRISCV32Target());
   RegisterTargetMachine<RISCVTargetMachine> Y(getTheRISCV64Target());
@@ -187,7 +192,7 @@ RISCVTargetMachine::RISCVTargetMachine(const Target &T, const Triple &TT,
   if (TT.isOSFuchsia() && !TT.isArch64Bit())
     report_fatal_error("Fuchsia is only supported for 64-bit");
 
-  setCFIFixup(true);
+  setCFIFixup(!EnableCFIInstrInserter);
 }
 
 const RISCVSubtarget *
@@ -584,6 +589,9 @@ void RISCVPassConfig::addPreEmitPass2() {
   addPass(createUnpackMachineBundles([&](const MachineFunction &MF) {
     return MF.getFunction().getParent()->getModuleFlag("kcfi");
   }));
+
+  if (EnableCFIInstrInserter)
+    addPass(createCFIInstrInserter());
 }
 
 void RISCVPassConfig::addMachineSSAOptimization() {

llvm/test/CodeGen/RISCV/cfi-escape.mir

@@ -0,0 +1,88 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc %s -mtriple=riscv64 -mattr=+v \
+# RUN: -run-pass=prologepilog,cfi-instr-inserter  \
+# RUN: -riscv-enable-cfi-instr-inserter=true \
+# RUN: | FileCheck %s
+#
+# In this test prolog will be inserted in bb.3. We need to save the scalable vector register v1.
+# This will emit cfi_escape in bb.3. We need to emit the same cfi_escape in the begining of bb.2.
+# Currently, CFIInstrInserter doesn't handle escape, so we have wrong cfi in this example.
+
+--- |
+
+  define riscv_vector_cc void @test0(ptr %p0, ptr %p1) #0 {
+    entry:
+    %v = load <4 x i32>, ptr %p0, align 16
+    store <4 x i32> %v, ptr %p1, align 16
+    ret void
+  }
+
+  attributes #0 = { "target-features"="+v" }
+
+...
+---
+name:            test0
+tracksRegLiveness: true
+frameInfo:
+  savePoint:       '%bb.3'
+  restorePoint:    '%bb.2'
+body:             |
+  ; CHECK-LABEL: name: test0
+  ; CHECK: bb.0.entry:
+  ; CHECK-NEXT:   successors: %bb.3(0x40000000), %bb.1(0x40000000)
+  ; CHECK-NEXT:   liveins: $x10, $x11, $v1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   BEQ $x10, $x0, %bb.3
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1:
+  ; CHECK-NEXT:   liveins: $v1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   PseudoRET
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2:
+  ; CHECK-NEXT:   successors: %bb.1(0x80000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   CFI_INSTRUCTION def_cfa_offset 16
+  ; CHECK-NEXT:   $x10 = ADDI $x2, 16
+  ; CHECK-NEXT:   $v1 = frame-destroy VL1RE8_V killed $x10 :: (load unknown-size from %stack.0, align 8)
+  ; CHECK-NEXT:   $x10 = frame-destroy PseudoReadVLENB
+  ; CHECK-NEXT:   $x2 = frame-destroy ADD $x2, killed $x10
+  ; CHECK-NEXT:   frame-destroy CFI_INSTRUCTION def_cfa $x2, 16
+  ; CHECK-NEXT:   frame-destroy CFI_INSTRUCTION restore $v1
+  ; CHECK-NEXT:   $x2 = frame-destroy ADDI $x2, 16
+  ; CHECK-NEXT:   frame-destroy CFI_INSTRUCTION def_cfa_offset 0
+  ; CHECK-NEXT:   PseudoBR %bb.1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.3:
+  ; CHECK-NEXT:   successors: %bb.2(0x80000000)
+  ; CHECK-NEXT:   liveins: $x10, $x11, $v1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   $x2 = frame-setup ADDI $x2, -16
+  ; CHECK-NEXT:   frame-setup CFI_INSTRUCTION def_cfa_offset 16
+  ; CHECK-NEXT:   $x12 = frame-setup PseudoReadVLENB
+  ; CHECK-NEXT:   $x2 = frame-setup SUB $x2, killed $x12
+  ; CHECK-NEXT:   frame-setup CFI_INSTRUCTION escape 0x0f, 0x0d, 0x72, 0x00, 0x11, 0x10, 0x22, 0x11, 0x01, 0x92, 0xa2, 0x38, 0x00, 0x1e, 0x22
+  ; CHECK-NEXT:   $x12 = ADDI $x2, 16
+  ; CHECK-NEXT:   frame-setup VS1R_V killed $v1, killed $x12 :: (store unknown-size into %stack.0, align 8)
+  ; CHECK-NEXT:   frame-setup CFI_INSTRUCTION escape 0x10, 0x61, 0x08, 0x11, 0x7f, 0x92, 0xa2, 0x38, 0x00, 0x1e, 0x22
+  ; CHECK-NEXT:   dead $x0 = PseudoVSETIVLI 4, 208 /* e32, m1, ta, ma */, implicit-def $vl, implicit-def $vtype
+  ; CHECK-NEXT:   renamable $v1 = PseudoVLE32_V_M1 undef renamable $v1, killed renamable $x10, 4, 5 /* e32 */, 2 /* tu, ma */, implicit $vl, implicit $vtype
+  ; CHECK-NEXT:   PseudoVSE32_V_M1 killed renamable $v1, killed renamable $x11, 4, 5 /* e32 */, implicit $vl, implicit $vtype
+  ; CHECK-NEXT:   PseudoBR %bb.2
+  bb.0.entry:
+    liveins: $x10, $x11
+    BEQ $x10, $x0, %bb.3
+
+  bb.1:
+    PseudoRET
+
+  bb.2:
+    PseudoBR %bb.1
+
+  bb.3:
+    liveins: $x10, $x11
+    dead $x0 = PseudoVSETIVLI 4, 208, implicit-def $vl, implicit-def $vtype
+    renamable $v1 = PseudoVLE32_V_M1 undef renamable $v1, killed renamable $x10, 4, 5, 2, implicit $vl, implicit $vtype
+    PseudoVSE32_V_M1 killed renamable $v1, killed renamable $x11, 4, 5, implicit $vl, implicit $vtype
+    PseudoBR %bb.2
+...

llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir

@@ -0,0 +1,35 @@
+# RUN: llc %s -mtriple=riscv64 \
+# RUN: -run-pass=cfi-instr-inserter \
+# RUN: -riscv-enable-cfi-instr-inserter=true \
+# RUN: | FileCheck %s
+# XFAIL: *
+
+# Technically, it is possible that the a callee-saved register is saved in different locations.
+# CFIInstrInserter should handle this, but currently it does not.
+---
+name: multiple_locations
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $x10, $x9, $x2
+    BEQ $x10, $x0, %bb.3
+
+  bb.1:
+    liveins: $x10, $x9, $x2
+    $x5 = COPY $x9
+    CFI_INSTRUCTION register $x9, $x5
+    $x9 = COPY $x5
+    CFI_INSTRUCTION register $x9, $x9
+    PseudoBR %bb.3
+
+  bb.2:
+    liveins: $x10, $x9, $x2
+    SD $x10, $x2, 0 :: (store (s64))
+    CFI_INSTRUCTION offset $x9, 0
+    $x10  = LD $x2, 0 :: (load (s64))
+    CFI_INSTRUCTION register $x9, $x9
+    PseudoBR %bb.1
+
+  bb.3:
+    PseudoRET
+...