[llvm] [CFIInstrInserter] A test showing the need to handle `cfi_escape`. (PR #128211)
Mikhail Gudim via llvm-commits
llvm-commits at lists.llvm.org
Mon Feb 24 05:22:35 PST 2025
https://github.com/mgudim updated https://github.com/llvm/llvm-project/pull/128211
>From a925cc8d12f84b1bbccac31cbf3b345ec5de8189 Mon Sep 17 00:00:00 2001
From: Mikhail Gudim <mgudim at ventanamicro.com>
Date: Fri, 21 Feb 2025 09:57:31 -0800
Subject: [PATCH] [CFIInstrInserter] Tests for scenarios not currently handled
by `CFIInstrInserter`.
We add an option to enable `CFIInstrInserter` on RISCV (`false` by
default). On RISCV there exists a realistic scenario (involing scalable
vectors) where we need CFIInstrInserter to handle `cfi_escape`. We add a
test for that. Also, we add a test for the scenario when a callee-saved
register is saved at different locations.
---
llvm/lib/Target/RISCV/RISCVFrameLowering.cpp | 9 ++
llvm/lib/Target/RISCV/RISCVFrameLowering.h | 2 +
llvm/lib/Target/RISCV/RISCVTargetMachine.cpp | 10 ++-
llvm/test/CodeGen/RISCV/cfi-escape.mir | 88 +++++++++++++++++++
.../CodeGen/RISCV/cfi-multiple-locations.mir | 35 ++++++++
5 files changed, 143 insertions(+), 1 deletion(-)
create mode 100644 llvm/test/CodeGen/RISCV/cfi-escape.mir
create mode 100644 llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir
diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp b/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
index 6abf45591d78e..96b0ef0ec40aa 100644
--- a/llvm/lib/Target/RISCV/RISCVFrameLowering.cpp
+++ b/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;
+}
diff --git a/llvm/lib/Target/RISCV/RISCVFrameLowering.h b/llvm/lib/Target/RISCV/RISCVFrameLowering.h
index d013755ce58a0..faad93a513258 100644
--- a/llvm/lib/Target/RISCV/RISCVFrameLowering.h
+++ b/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
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index 167dbb53c5950..2be3981f2b815 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/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() {
diff --git a/llvm/test/CodeGen/RISCV/cfi-escape.mir b/llvm/test/CodeGen/RISCV/cfi-escape.mir
new file mode 100644
index 0000000000000..a15825caa9fb8
--- /dev/null
+++ b/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
+...
diff --git a/llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir b/llvm/test/CodeGen/RISCV/cfi-multiple-locations.mir
new file mode 100644
index 0000000000000..f40a55a29d15f
--- /dev/null
+++ b/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
+...
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