From 336da8cdc506c4f13e9a37ad33a6c0be83e4c5f4 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand Date: Wed, 18 Jun 2014 16:14:04 +0000 Subject: [PATCH] [PowerPC] Do not use BLA with the 64-bit SVR4 ABI The PowerPC back-end uses BLA to implement calls to functions at known-constant addresses, which is apparently used for certain system routines on Darwin. However, with the 64-bit SVR4 ABI, this is actually incorrect. An immediate function pointer value on this platform is not directly usable as a target address for BLA: - in the ELFv1 ABI, the function pointer value refers to the *function descriptor*, not the code address - in the ELFv2 ABI, the function pointer value refers to the global entry point, but BL(A) would only be correct when calling the *local* entry point This bug didn't show up since using immediate function pointer values is not usually done in the 64-bit SVR4 ABI in the first place. However, I ran into this issue with a certain use case of LLVM as JIT, where immediate function pointer values were uses to implement callbacks from JITted code to helpers in statically compiled code. Fixed by simply not using BLA with the 64-bit SVR4 ABI. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211174 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/PowerPC/PPCISelLowering.cpp | 14 +++++++------- test/CodeGen/PowerPC/ppc64-calls.ll | 9 --------- 2 files changed, 7 insertions(+), 16 deletions(-) diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp index 1db9070267a..e815d615acb 100644 --- a/lib/Target/PowerPC/PPCISelLowering.cpp +++ b/lib/Target/PowerPC/PPCISelLowering.cpp @@ -3431,11 +3431,12 @@ unsigned PrepareCall(SelectionDAG &DAG, SDValue &Callee, SDValue &InFlag, unsigned CallOpc = PPCISD::CALL; bool needIndirectCall = true; - if (SDNode *Dest = isBLACompatibleAddress(Callee, DAG)) { - // If this is an absolute destination address, use the munged value. - Callee = SDValue(Dest, 0); - needIndirectCall = false; - } + if (!isSVR4ABI || !isPPC64) + if (SDNode *Dest = isBLACompatibleAddress(Callee, DAG)) { + // If this is an absolute destination address, use the munged value. + Callee = SDValue(Dest, 0); + needIndirectCall = false; + } if (GlobalAddressSDNode *G = dyn_cast(Callee)) { // XXX Work around for http://llvm.org/bugs/show_bug.cgi?id=5201 @@ -4383,8 +4384,7 @@ PPCTargetLowering::LowerCall_64SVR4(SDValue Chain, SDValue Callee, // pointers in the 64-bit SVR4 ABI. if (!isTailCall && !dyn_cast(Callee) && - !dyn_cast(Callee) && - !isBLACompatibleAddress(Callee, DAG)) { + !dyn_cast(Callee)) { // Load r2 into a virtual register and store it to the TOC save area. SDValue Val = DAG.getCopyFromReg(Chain, dl, PPC::X2, MVT::i64); // TOC save area offset. diff --git a/test/CodeGen/PowerPC/ppc64-calls.ll b/test/CodeGen/PowerPC/ppc64-calls.ll index 1f3bb7111ef..396a5e25caf 100644 --- a/test/CodeGen/PowerPC/ppc64-calls.ll +++ b/test/CodeGen/PowerPC/ppc64-calls.ll @@ -42,15 +42,6 @@ define void @test_indirect(void ()* nocapture %fp) nounwind { ret void } -; Absolute vales should be have the TOC restore 'nop' -define void @test_abs() nounwind { -; CHECK-LABEL: test_abs: - tail call void inttoptr (i64 1024 to void ()*)() nounwind -; CHECK: bla 1024 -; CHECK-NEXT: nop - ret void -} - declare double @sin(double) nounwind ; External functions call should also have a 'nop' -- 2.34.1