[llvm] [X86] Fix SLH crash on llvm.eh.sjlh.longjmp (PR #77959)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-x86

Author: Nicholas Mosier (nmosier)

<details>
<summary>Changes</summary>

Fix #<!-- -->60081.

---
Full diff: https://github.com/llvm/llvm-project/pull/77959.diff


2 Files Affected:

- (modified) llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp (+1) 
- (modified) llvm/test/CodeGen/X86/speculative-load-hardening.ll (+31) 


``````````diff
diff --git a/llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp b/llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp
index 6301285fe95457..901b7e8cc36d4f 100644
--- a/llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp
+++ b/llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp
@@ -1366,6 +1366,7 @@ void X86SpeculativeLoadHardeningPass::tracePredStateThroughBlocksAndHarden(
         if (EnablePostLoadHardening && X86InstrInfo::isDataInvariantLoad(MI) &&
             !isEFLAGSDefLive(MI) && MI.getDesc().getNumDefs() == 1 &&
             MI.getOperand(0).isReg() &&
+            MI.getOperand(0).getReg().isVirtual() &&
             canHardenRegister(MI.getOperand(0).getReg()) &&
             !HardenedAddrRegs.count(BaseReg) &&
             !HardenedAddrRegs.count(IndexReg)) {
diff --git a/llvm/test/CodeGen/X86/speculative-load-hardening.ll b/llvm/test/CodeGen/X86/speculative-load-hardening.ll
index 0c47fcddc43af2..83eceda8743223 100644
--- a/llvm/test/CodeGen/X86/speculative-load-hardening.ll
+++ b/llvm/test/CodeGen/X86/speculative-load-hardening.ll
@@ -1161,3 +1161,34 @@ define void @idempotent_atomic(ptr %x) speculative_load_hardening {
   %tmp = atomicrmw or ptr %x, i32 0 seq_cst
   ret void
 }
+
+; Make sure we don't crash on longjmps (PR60081).
+declare void @llvm.eh.sjlj.longjmp(ptr)
+define void @test_physical_register_defs(ptr %env) speculative_load_hardening {
+; X64-LABEL: test_physical_register_defs:
+; X64:       # %bb.0:
+; X64-NEXT:    pushq %rbp
+; X64-NEXT:    .cfi_def_cfa_offset 16
+; X64-NEXT:    .cfi_offset %rbp, -16
+; X64-NEXT:    movq %rsp, %rax
+; X64-NEXT:    movq $-1, %rcx
+; X64-NEXT:    sarq $63, %rax
+; X64-NEXT:    orq %rax, %rdi
+; X64-NEXT:    movq (%rdi), %rbp
+; X64-NEXT:    movq 8(%rdi), %rcx
+; X64-NEXT:    movq 16(%rdi), %rsp
+; X64-NEXT:    orq %rax, %rcx
+; X64-NEXT:    jmpq *%rcx
+;
+; X64-LFENCE-LABEL: test_physical_register_defs:
+; X64-LFENCE:       # %bb.0:
+; X64-LFENCE-NEXT:    pushq %rbp
+; X64-LFENCE-NEXT:    .cfi_def_cfa_offset 16
+; X64-LFENCE-NEXT:    .cfi_offset %rbp, -16
+; X64-LFENCE-NEXT:    movq (%rdi), %rbp
+; X64-LFENCE-NEXT:    movq 8(%rdi), %rax
+; X64-LFENCE-NEXT:    movq 16(%rdi), %rsp
+; X64-LFENCE-NEXT:    jmpq *%rax
+  call void @llvm.eh.sjlj.longjmp(ptr %env)
+  unreachable
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/77959