[PATCH] D122634: [RISCV] Do not outline CFI instructions when they are needed in EH

[Wang Pengcheng via Phabricator via llvm-commits]

pcwang-thead updated this revision to Diff 421434.
pcwang-thead added a comment.

Rebase on precommit test D123364 <https://reviews.llvm.org/D123364>.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D122634/new/

https://reviews.llvm.org/D122634

Files:
  llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
  llvm/test/CodeGen/RISCV/machine-outliner-throw.ll


Index: llvm/test/CodeGen/RISCV/machine-outliner-throw.ll
===================================================================
--- llvm/test/CodeGen/RISCV/machine-outliner-throw.ll
+++ llvm/test/CodeGen/RISCV/machine-outliner-throw.ll
@@ -4,7 +4,15 @@
 define i32 @func1(i32 %x) #0 {
 ; CHECK-LABEL: func1:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    call t0, OUTLINED_FUNCTION_0
+; CHECK-NEXT:    addi sp, sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_offset ra, -8
+; CHECK-NEXT:    .cfi_offset s0, -16
+; CHECK-NEXT:    mulw a0, a0, a0
+; CHECK-NEXT:    addiw s0, a0, 1
+; CHECK-NEXT:    li a0, 4
 ; CHECK-NEXT:    call __cxa_allocate_exception at plt
 ; CHECK-NEXT:    sw s0, 0(a0)
 ; CHECK-NEXT:    lui a1, %hi(_ZTIi)
@@ -24,7 +32,15 @@
 define i32 @func2(i32 %x) #0 {
 ; CHECK-LABEL: func2:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    call t0, OUTLINED_FUNCTION_0
+; CHECK-NEXT:    addi sp, sp, -16
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    sd s0, 0(sp) # 8-byte Folded Spill
+; CHECK-NEXT:    .cfi_offset ra, -8
+; CHECK-NEXT:    .cfi_offset s0, -16
+; CHECK-NEXT:    mulw a0, a0, a0
+; CHECK-NEXT:    addiw s0, a0, 1
+; CHECK-NEXT:    li a0, 4
 ; CHECK-NEXT:    call __cxa_allocate_exception at plt
 ; CHECK-NEXT:    sw s0, 0(a0)
 ; CHECK-NEXT:    lui a1, %hi(_ZTIi)
@@ -41,15 +57,6 @@
   unreachable
 }
 
-; CHECK-LABEL: OUTLINED_FUNCTION_0:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    addi sp, sp, -16
-; CHECK-NEXT:    sd ra, 8(sp)
-; CHECK-NEXT:    sd s0, 0(sp)
-; CHECK-NEXT:    mulw a0, a0, a0
-; CHECK-NEXT:    addiw s0, a0, 1
-; CHECK-NEXT:    li a0, 4
-
 @_ZTIi = external constant i8*
 declare i8* @__cxa_allocate_exception(i64)
 declare void @__cxa_throw(i8*, i8*, i8*)
Index: llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -1246,7 +1246,12 @@
   if (MI.isPosition()) {
     // We can manually strip out CFI instructions later.
     if (MI.isCFIInstruction())
-      return outliner::InstrType::Invisible;
+      // If current function has exception handling code, we can't outline &
+      // strip these CFI instructions since it may break .eh_frame section
+      // needed in unwinding.
+      return MI.getMF()->getFunction().needsUnwindTableEntry()
+                 ? outliner::InstrType::Illegal
+                 : outliner::InstrType::Invisible;
 
     return outliner::InstrType::Illegal;
   }


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