[PATCH] D38251: [X86] Remove erroneous callsite offsetting in SJLJ landing pads

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
Herald added subscribers: kristof.beyls, aemerson.

The callsite value is already stored indexed from 0 in the _Unwind_Context struct. When accessed via the functions _Unwind_GetIP and _Unwind_SetIP, the value is indexed from 1, but those functions handle the offseting. When reading directly from the struct here, we shouldn't subtract 1.

This matches the code generated by the ARM target, where SJLJ exception handling is used by default on iOS.


https://reviews.llvm.org/D38251

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/sjlj-eh.ll


Index: test/CodeGen/X86/sjlj-eh.ll
===================================================================
--- test/CodeGen/X86/sjlj-eh.ll
+++ test/CodeGen/X86/sjlj-eh.ll
@@ -63,10 +63,9 @@
 ;     assert(UFC.__callsite <= 1);
 ; CHECK: movl -60(%ebp), %eax
 ; CHECK: cmpl $1, %eax
-; CHECK: jbe [[CONT:LBB[0-9]+_[0-9]+]]
+; CHECK: jb [[CONT:LBB[0-9]+_[0-9]+]]
 ; CHECK: ud2
 ; CHECK: [[CONT]]:
-;     *Handlers[--UFC.__callsite]
-; CHECK: subl $1, %eax
+;     *Handlers[UFC.__callsite]
 ; CHECK: jmpl *LJTI
 
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -26574,17 +26574,13 @@
   BuildMI(DispatchBB, DL, TII->get(X86::CMP32ri))
       .addReg(IReg)
       .addImm(LPadList.size());
-  BuildMI(DispatchBB, DL, TII->get(X86::JA_1)).addMBB(TrapBB);
+  BuildMI(DispatchBB, DL, TII->get(X86::JAE_1)).addMBB(TrapBB);
 
-  unsigned JReg = MRI->createVirtualRegister(&X86::GR32RegClass);
-  BuildMI(DispContBB, DL, TII->get(X86::SUB32ri), JReg)
-      .addReg(IReg)
-      .addImm(1);
   BuildMI(DispContBB, DL,
           TII->get(Subtarget.is64Bit() ? X86::JMP64m : X86::JMP32m))
       .addReg(0)
       .addImm(Subtarget.is64Bit() ? 8 : 4)
-      .addReg(JReg)
+      .addReg(IReg)
       .addJumpTableIndex(MJTI)
       .addReg(0);
 


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