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https://github.com/RPCS3/llvm-mirror.git
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54e8749794
This pass implements whole program optimization of virtual calls in cases where we know (via bitset information) that the list of callees is fixed. This includes the following: - Single implementation devirtualization: if a virtual call has a single possible callee, replace all calls with a direct call to that callee. - Virtual constant propagation: if the virtual function's return type is an integer <=64 bits and all possible callees are readnone, for each class and each list of constant arguments: evaluate the function, store the return value alongside the virtual table, and rewrite each virtual call as a load from the virtual table. - Uniform return value optimization: if the conditions for virtual constant propagation hold and each function returns the same constant value, replace each virtual call with that constant. - Unique return value optimization for i1 return values: if the conditions for virtual constant propagation hold and a single vtable's function returns 0, or a single vtable's function returns 1, replace each virtual call with a comparison of the vptr against that vtable's address. Differential Revision: http://reviews.llvm.org/D16795 llvm-svn: 260312
132 lines
5.5 KiB
LLVM
132 lines
5.5 KiB
LLVM
; RUN: opt -S -wholeprogramdevirt %s | FileCheck %s
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target datalayout = "e-p:64:64"
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target triple = "x86_64-unknown-linux-gnu"
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; CHECK: [[VT1DATA:@[^ ]*]] = private constant { [0 x i8], [4 x i8*], [8 x i8] } { [0 x i8] zeroinitializer, [4 x i8*] [i8* null, i8* bitcast (i1 (i8*)* @vf0i1 to i8*), i8* bitcast (i1 (i8*)* @vf1i1 to i8*), i8* bitcast (i32 (i8*)* @vf1i32 to i8*)], [8 x i8] c"\01\00\00\00\01\00\00\00" }
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@vt1 = constant [4 x i8*] [
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i8* null,
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i8* bitcast (i1 (i8*)* @vf0i1 to i8*),
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i8* bitcast (i1 (i8*)* @vf1i1 to i8*),
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i8* bitcast (i32 (i8*)* @vf1i32 to i8*)
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]
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; CHECK: [[VT2DATA:@[^ ]*]] = private constant { [0 x i8], [3 x i8*], [8 x i8] } { [0 x i8] zeroinitializer, [3 x i8*] [i8* bitcast (i1 (i8*)* @vf1i1 to i8*), i8* bitcast (i1 (i8*)* @vf0i1 to i8*), i8* bitcast (i32 (i8*)* @vf2i32 to i8*)], [8 x i8] c"\02\00\00\00\02\00\00\00" }
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@vt2 = constant [3 x i8*] [
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i8* bitcast (i1 (i8*)* @vf1i1 to i8*),
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i8* bitcast (i1 (i8*)* @vf0i1 to i8*),
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i8* bitcast (i32 (i8*)* @vf2i32 to i8*)
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]
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; CHECK: [[VT3DATA:@[^ ]*]] = private constant { [0 x i8], [4 x i8*], [8 x i8] } { [0 x i8] zeroinitializer, [4 x i8*] [i8* null, i8* bitcast (i1 (i8*)* @vf0i1 to i8*), i8* bitcast (i1 (i8*)* @vf1i1 to i8*), i8* bitcast (i32 (i8*)* @vf3i32 to i8*)], [8 x i8] c"\03\00\00\00\01\00\00\00" }
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@vt3 = constant [4 x i8*] [
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i8* null,
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i8* bitcast (i1 (i8*)* @vf0i1 to i8*),
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i8* bitcast (i1 (i8*)* @vf1i1 to i8*),
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i8* bitcast (i32 (i8*)* @vf3i32 to i8*)
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]
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; CHECK: [[VT4DATA:@[^ ]*]] = private constant { [0 x i8], [3 x i8*], [8 x i8] } { [0 x i8] zeroinitializer, [3 x i8*] [i8* bitcast (i1 (i8*)* @vf1i1 to i8*), i8* bitcast (i1 (i8*)* @vf0i1 to i8*), i8* bitcast (i32 (i8*)* @vf4i32 to i8*)], [8 x i8] c"\04\00\00\00\02\00\00\00" }
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@vt4 = constant [3 x i8*] [
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i8* bitcast (i1 (i8*)* @vf1i1 to i8*),
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i8* bitcast (i1 (i8*)* @vf0i1 to i8*),
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i8* bitcast (i32 (i8*)* @vf4i32 to i8*)
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]
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; CHECK: @vt1 = alias [4 x i8*], getelementptr inbounds ({ [0 x i8], [4 x i8*], [8 x i8] }, { [0 x i8], [4 x i8*], [8 x i8] }* [[VT1DATA]], i32 0, i32 1)
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; CHECK: @vt2 = alias [3 x i8*], getelementptr inbounds ({ [0 x i8], [3 x i8*], [8 x i8] }, { [0 x i8], [3 x i8*], [8 x i8] }* [[VT2DATA]], i32 0, i32 1)
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; CHECK: @vt3 = alias [4 x i8*], getelementptr inbounds ({ [0 x i8], [4 x i8*], [8 x i8] }, { [0 x i8], [4 x i8*], [8 x i8] }* [[VT3DATA]], i32 0, i32 1)
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; CHECK: @vt4 = alias [3 x i8*], getelementptr inbounds ({ [0 x i8], [3 x i8*], [8 x i8] }, { [0 x i8], [3 x i8*], [8 x i8] }* [[VT4DATA]], i32 0, i32 1)
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define i1 @vf0i1(i8* %this) readnone {
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ret i1 0
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}
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define i1 @vf1i1(i8* %this) readnone {
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ret i1 1
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}
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define i32 @vf1i32(i8* %this) readnone {
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ret i32 1
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}
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define i32 @vf2i32(i8* %this) readnone {
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ret i32 2
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}
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define i32 @vf3i32(i8* %this) readnone {
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ret i32 3
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}
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define i32 @vf4i32(i8* %this) readnone {
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ret i32 4
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}
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; CHECK: define i1 @call1(
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define i1 @call1(i8* %obj) {
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%vtableptr = bitcast i8* %obj to [3 x i8*]**
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%vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
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; CHECK: [[VT1:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
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%vtablei8 = bitcast [3 x i8*]* %vtable to i8*
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%p = call i1 @llvm.bitset.test(i8* %vtablei8, metadata !"bitset")
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call void @llvm.assume(i1 %p)
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%fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 0
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%fptr = load i8*, i8** %fptrptr
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%fptr_casted = bitcast i8* %fptr to i1 (i8*)*
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; CHECK: [[VTGEP1:%[^ ]*]] = getelementptr i8, i8* [[VT1]], i64 28
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; CHECK: [[VTLOAD1:%[^ ]*]] = load i8, i8* [[VTGEP1]]
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; CHECK: [[VTAND1:%[^ ]*]] = and i8 [[VTLOAD1]], 2
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; CHECK: [[VTCMP1:%[^ ]*]] = icmp ne i8 [[VTAND1]], 0
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%result = call i1 %fptr_casted(i8* %obj)
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; CHECK: ret i1 [[VTCMP1]]
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ret i1 %result
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}
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; CHECK: define i1 @call2(
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define i1 @call2(i8* %obj) {
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%vtableptr = bitcast i8* %obj to [3 x i8*]**
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%vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
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; CHECK: [[VT2:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
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%vtablei8 = bitcast [3 x i8*]* %vtable to i8*
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%p = call i1 @llvm.bitset.test(i8* %vtablei8, metadata !"bitset")
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call void @llvm.assume(i1 %p)
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%fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 1
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%fptr = load i8*, i8** %fptrptr
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%fptr_casted = bitcast i8* %fptr to i1 (i8*)*
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; CHECK: [[VTGEP2:%[^ ]*]] = getelementptr i8, i8* [[VT2]], i64 28
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; CHECK: [[VTLOAD2:%[^ ]*]] = load i8, i8* [[VTGEP2]]
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; CHECK: [[VTAND2:%[^ ]*]] = and i8 [[VTLOAD2]], 1
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; CHECK: [[VTCMP2:%[^ ]*]] = icmp ne i8 [[VTAND2]], 0
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%result = call i1 %fptr_casted(i8* %obj)
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; CHECK: ret i1 [[VTCMP2]]
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ret i1 %result
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}
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; CHECK: define i32 @call3(
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define i32 @call3(i8* %obj) {
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%vtableptr = bitcast i8* %obj to [3 x i8*]**
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%vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
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; CHECK: [[VT3:%[^ ]*]] = bitcast [3 x i8*]* {{.*}} to i8*
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%vtablei8 = bitcast [3 x i8*]* %vtable to i8*
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%p = call i1 @llvm.bitset.test(i8* %vtablei8, metadata !"bitset")
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call void @llvm.assume(i1 %p)
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%fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 2
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%fptr = load i8*, i8** %fptrptr
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%fptr_casted = bitcast i8* %fptr to i32 (i8*)*
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; CHECK: [[VTGEP3:%[^ ]*]] = getelementptr i8, i8* [[VT3]], i64 24
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; CHECK: [[VTBC3:%[^ ]*]] = bitcast i8* [[VTGEP3]] to i32*
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; CHECK: [[VTLOAD3:%[^ ]*]] = load i32, i32* [[VTBC3]]
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%result = call i32 %fptr_casted(i8* %obj)
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; CHECK: ret i32 [[VTLOAD3]]
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ret i32 %result
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}
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declare i1 @llvm.bitset.test(i8*, metadata)
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declare void @llvm.assume(i1)
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!0 = !{!"bitset", [4 x i8*]* @vt1, i32 8}
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!1 = !{!"bitset", [3 x i8*]* @vt2, i32 0}
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!2 = !{!"bitset", [4 x i8*]* @vt3, i32 8}
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!3 = !{!"bitset", [3 x i8*]* @vt4, i32 0}
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!llvm.bitsets = !{!0, !1, !2, !3}
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