From 8a0d41e1a649c32e1f0e22c6c201a2e0d8463e30 Mon Sep 17 00:00:00 2001 From: Derek Schuff Date: Fri, 14 Jun 2013 16:15:29 +0000 Subject: [PATCH] Make PrologEpilogInserter save/restore all callee saved registers in functions which call __builtin_unwind_init() __builtin_unwind_init() is an undocumented gcc intrinsic which has this effect, and is used in libgcc_eh. Goes part of the way toward fixing PR8541. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183984 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/IR/Intrinsics.td | 3 +++ lib/CodeGen/PrologEpilogInserter.cpp | 4 +++- test/CodeGen/ARM/unwind-init.ll | 18 ++++++++++++++ test/CodeGen/X86/unwind-init.ll | 36 ++++++++++++++++++++++++++++ 4 files changed, 60 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/ARM/unwind-init.ll create mode 100644 test/CodeGen/X86/unwind-init.ll diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td index e252664e45c..65301876633 100644 --- a/include/llvm/IR/Intrinsics.td +++ b/include/llvm/IR/Intrinsics.td @@ -347,6 +347,9 @@ def int_eh_typeid_for : Intrinsic<[llvm_i32_ty], [llvm_ptr_ty], [IntrNoMem]>; def int_eh_return_i32 : Intrinsic<[], [llvm_i32_ty, llvm_ptr_ty]>; def int_eh_return_i64 : Intrinsic<[], [llvm_i64_ty, llvm_ptr_ty]>; +// __builtin_unwind_init is an undocumented GCC intrinsic that causes all +// callee-saved registers to be saved and restored (regardless of whether they +// are used) in the calling function. It is used by libgcc_eh. def int_eh_unwind_init: Intrinsic<[]>, GCCBuiltin<"__builtin_unwind_init">; diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp index 4b301d84ca4..9f2cba2195f 100644 --- a/lib/CodeGen/PrologEpilogInserter.cpp +++ b/lib/CodeGen/PrologEpilogInserter.cpp @@ -29,6 +29,7 @@ #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/MachineLoopInfo.h" +#include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/RegisterScavenging.h" #include "llvm/IR/InlineAsm.h" @@ -227,7 +228,8 @@ void PEI::calculateCalleeSavedRegisters(MachineFunction &F) { std::vector CSI; for (unsigned i = 0; CSRegs[i]; ++i) { unsigned Reg = CSRegs[i]; - if (F.getRegInfo().isPhysRegUsed(Reg)) { + // Functions which call __builtin_unwind_init get all their registers saved. + if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) { // If the reg is modified, save it! CSI.push_back(CalleeSavedInfo(Reg)); } diff --git a/test/CodeGen/ARM/unwind-init.ll b/test/CodeGen/ARM/unwind-init.ll new file mode 100644 index 00000000000..11683d56053 --- /dev/null +++ b/test/CodeGen/ARM/unwind-init.ll @@ -0,0 +1,18 @@ +; RUN: llc -mtriple=armv7-unknown-linux-gnueabi < %s | FileCheck %s +; Check that all callee-saved registers are saved and restored in functions +; that call __builtin_unwind_init(). This is its undocumented behavior in gcc, +; and it is used in compiling libgcc_eh. +; See also PR8541 + +declare void @llvm.eh.unwind.init() + +define void @calls_unwind_init() { + call void @llvm.eh.unwind.init() + ret void +} + +; CHECK: calls_unwind_init: +; CHECK: push {r4, r5, r6, r7, r8, r9, r10, r11, lr} +; CHECK: vpush {d8, d9, d10, d11, d12, d13, d14, d15} +; CHECK: vpop {d8, d9, d10, d11, d12, d13, d14, d15} +; CHECK: pop {r4, r5, r6, r7, r8, r9, r10, r11, pc} diff --git a/test/CodeGen/X86/unwind-init.ll b/test/CodeGen/X86/unwind-init.ll new file mode 100644 index 00000000000..e34178d8722 --- /dev/null +++ b/test/CodeGen/X86/unwind-init.ll @@ -0,0 +1,36 @@ +; RUN: llc -mtriple=x86_64-unknown-linux < %s | FileCheck -check-prefix X8664 %s +; RUN: llc -mtriple=i686-unknown-linux < %s | FileCheck -check-prefix X8632 %s +; Check that all callee-saved registers are saved and restored in functions +; that call __builtin_unwind_init(). This is its undocumented behavior in gcc, +; and it is used in compiling libgcc_eh. +; See also PR8541 + +declare void @llvm.eh.unwind.init() + +define void @calls_unwind_init() { + call void @llvm.eh.unwind.init() + ret void +} + +; X8664: calls_unwind_init: +; X8664: pushq %rbp +; X8664: pushq %r15 +; X8664: pushq %r14 +; X8664: pushq %r13 +; X8664: pushq %r12 +; X8664: pushq %rbx +; X8664: popq %rbx +; X8664: popq %r12 +; X8664: popq %r13 +; X8664: popq %r14 +; X8664: popq %r15 + +; X8632: calls_unwind_init: +; X8632: pushl %ebp +; X8632: pushl %ebx +; X8632: pushl %edi +; X8632: pushl %esi +; X8632: popl %esi +; X8632: popl %edi +; X8632: popl %ebx +; X8632: popl %ebp -- 2.34.1