From 711dec260fc5ad2ec48fe73351bbfb9bd6d843d8 Mon Sep 17 00:00:00 2001 From: Dean Michael Berris Date: Fri, 8 Sep 2017 01:47:56 +0000 Subject: [PATCH] [XRay][CodeGen][PowerPC] Fix tail exit codegen for XRay in PPC Summary: This fixes code-gen for XRay in PPC. The regression wasn't caught by codegen tests which we add in this change. What happened was the following: - For tail exits, we used to unconditionally prepend the returns/exits with a pseudo-instruction that gets lowered to the instrumentation sled (and leave the actual return/exit instruction as-is). - Changes to the XRay instrumentation pass caused the tail exits to suddenly also emit the tail exit pseudo-instruction, since the check for whether a return instruction was also a call instruction meant it was a tail exit instruction. - None of the tests caught the regression either due to non-existent tests, or the tests being disabled/removed for continuous breakage. This change re-introduces some of the basic tests and verifies that we're back to a state that allows the back-end to generate appropriate XRay instrumented binaries for PPC in the presence of tail exits. Reviewers: echristo, timshen Subscribers: nemanjai, kbarton, llvm-commits Differential Revision: https://reviews.llvm.org/D37570 llvm-svn: 312772 --- llvm/lib/CodeGen/XRayInstrumentation.cpp | 23 +++------- llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp | 2 + .../PowerPC/xray-attribute-instrumentation.ll | 44 +++++++++++++++++++ .../CodeGen/PowerPC/xray-tail-call-hidden.ll | 26 +++++++++++ .../CodeGen/PowerPC/xray-tail-call-sled.ll | 44 +++++++++++++++++++ 5 files changed, 123 insertions(+), 16 deletions(-) create mode 100644 llvm/test/CodeGen/PowerPC/xray-attribute-instrumentation.ll create mode 100644 llvm/test/CodeGen/PowerPC/xray-tail-call-hidden.ll create mode 100644 llvm/test/CodeGen/PowerPC/xray-tail-call-sled.ll diff --git a/llvm/lib/CodeGen/XRayInstrumentation.cpp b/llvm/lib/CodeGen/XRayInstrumentation.cpp index 0b4c6e551667..e6b65825f5b5 100644 --- a/llvm/lib/CodeGen/XRayInstrumentation.cpp +++ b/llvm/lib/CodeGen/XRayInstrumentation.cpp @@ -14,8 +14,8 @@ // //===---------------------------------------------------------------------===// -#include "llvm/ADT/SmallVector.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Triple.h" #include "llvm/CodeGen/MachineBasicBlock.h" #include "llvm/CodeGen/MachineDominators.h" @@ -109,22 +109,13 @@ void XRayInstrumentation::replaceRetWithPatchableRet( void XRayInstrumentation::prependRetWithPatchableExit( MachineFunction &MF, const TargetInstrInfo *TII) { - for (auto &MBB : MF) { - for (auto &T : MBB.terminators()) { - unsigned Opc = 0; + for (auto &MBB : MF) + for (auto &T : MBB.terminators()) if (T.isReturn()) { - Opc = TargetOpcode::PATCHABLE_FUNCTION_EXIT; + // Prepend the return instruction with PATCHABLE_FUNCTION_EXIT. + BuildMI(MBB, T, T.getDebugLoc(), + TII->get(TargetOpcode::PATCHABLE_FUNCTION_EXIT)); } - if (TII->isTailCall(T)) { - Opc = TargetOpcode::PATCHABLE_TAIL_CALL; - } - if (Opc != 0) { - // Prepend the return instruction with PATCHABLE_FUNCTION_EXIT or - // PATCHABLE_TAIL_CALL . - BuildMI(MBB, T, T.getDebugLoc(), TII->get(Opc)); - } - } - } } bool XRayInstrumentation::runOnMachineFunction(MachineFunction &MF) { @@ -143,7 +134,7 @@ bool XRayInstrumentation::runOnMachineFunction(MachineFunction &MF) { // Count the number of MachineInstr`s in MachineFunction int64_t MICount = 0; - for (const auto& MBB : MF) + for (const auto &MBB : MF) MICount += MBB.size(); // Check if we have a loop. diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp index 841b8c514464..67c849b37bd8 100644 --- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp +++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp @@ -1131,6 +1131,8 @@ void PPCLinuxAsmPrinter::EmitInstruction(const MachineInstr *MI) { break; } case TargetOpcode::PATCHABLE_TAIL_CALL: + // TODO: Define a trampoline `__xray_FunctionTailExit` and differentiate a + // normal function exit from a tail exit. case TargetOpcode::PATCHABLE_RET: // PPC's tail call instruction, e.g. PPC::TCRETURNdi8, doesn't really // lower to a PPC::B instruction. The PPC::B instruction is generated diff --git a/llvm/test/CodeGen/PowerPC/xray-attribute-instrumentation.ll b/llvm/test/CodeGen/PowerPC/xray-attribute-instrumentation.ll new file mode 100644 index 000000000000..3592499a03e5 --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/xray-attribute-instrumentation.ll @@ -0,0 +1,44 @@ +; RUN: llc -filetype=asm -o - -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s +; RUN: llc -filetype=asm -o - -mtriple=powerpc64le-unknown-linux-gnu \ +; RUN: -relocation-model=pic < %s | FileCheck %s + +define i32 @foo() nounwind noinline uwtable "function-instrument"="xray-always" { +; CHECK-LABEL: .Ltmp0: +; CHECK: b .Ltmp1 +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionEntry +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +; CHECK-LABEL: .Ltmp1: + ret i32 0 +; CHECK-LABEL: .Ltmp2: +; CHECK: blr +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionExit +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +} +; CHECK-LABEL: xray_instr_map,"awo",@progbits,.text,unique,1 +; CHECK: .Lxray_sleds_start0: +; CHECK-NEXT: .quad .Ltmp0 +; CHECK-NEXT: .quad foo +; CHECK-NEXT: .byte 0x00 +; CHECK-NEXT: .byte 0x01 +; CHECK-NEXT: .byte 0x00 +; CHECK-NEXT: .space 13 +; CHECK-NEXT: .quad .Ltmp2 +; CHECK-NEXT: .quad foo +; CHECK-NEXT: .byte 0x01 +; CHECK-NEXT: .byte 0x01 +; CHECK-NEXT: .byte 0x00 +; CHECK-NEXT: .space 13 +; CHECK-NEXT: .Lxray_sleds_end0: +; CHECK-LABEL: xray_fn_idx,"awo",@progbits,.text,unique,1 +; CHECK: .p2align 4 +; CHECK-NEXT: .quad .Lxray_sleds_start0 +; CHECK-NEXT: .quad .Lxray_sleds_end0 +; CHECK-NEXT: .text diff --git a/llvm/test/CodeGen/PowerPC/xray-tail-call-hidden.ll b/llvm/test/CodeGen/PowerPC/xray-tail-call-hidden.ll new file mode 100644 index 000000000000..3b1cd5f5870d --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/xray-tail-call-hidden.ll @@ -0,0 +1,26 @@ +; RUN: llc -filetype=asm -o - -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s + +declare hidden i32 @callee() nounwind noinline uwtable "function-instrument"="xray-always" + +define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-always" { +; CHECK-LABEL: .Ltmp0: +; CHECK: b .Ltmp1 +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionEntry +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +; CHECK-LABEL: .Ltmp1: + %retval = tail call i32 @callee() + ret i32 %retval +; CHECK-LABEL: .Ltmp2: +; CHECK: b callee +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionExit +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +} + diff --git a/llvm/test/CodeGen/PowerPC/xray-tail-call-sled.ll b/llvm/test/CodeGen/PowerPC/xray-tail-call-sled.ll new file mode 100644 index 000000000000..e8fe9dbaa45f --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/xray-tail-call-sled.ll @@ -0,0 +1,44 @@ +; RUN: llc -filetype=asm -o - -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s + +define i32 @callee() nounwind noinline uwtable "function-instrument"="xray-always" { +; CHECK-LABEL: .Ltmp0: +; CHECK: b .Ltmp1 +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionEntry +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +; CHECK-LABEL: .Ltmp1: + ret i32 0 +; CHECK-LABEL: .Ltmp2: +; CHECK: blr +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionExit +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +} + +define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-always" { +; CHECK-LABEL: .Ltmp3: +; CHECK: b .Ltmp4 +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionEntry +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +; CHECK-LABEL: .Ltmp4: + %retval = tail call i32 @callee() + ret i32 %retval +; CHECK-LABEL: .Ltmp5: +; CHECK: blr +; CHECK-NEXT: nop +; CHECK-NEXT: std 0, -8(1) +; CHECK-NEXT: mflr 0 +; CHECK-NEXT: bl __xray_FunctionExit +; CHECK-NEXT: nop +; CHECK-NEXT: mtlr 0 +}