maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[GlobalOpt] Fix support for casts in ctors. 

Summary:
Fixing an issue where initializations of globals where constructors use
casts were silently translated to 0-initialization.

Reviewers: davidxl, evgeny777

Reviewed By: evgeny777

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45198

llvm-svn: 329409
This commit is contained in:
Mircea Trofin 2018-04-06 15:54:47 +00:00
parent 59399ae4cc
commit aa3fea6cb0
2 changed files with 67 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
llvm/lib/Transforms/Utils/Evaluator.cpp
View File

@ -203,7 +203,11 @@ Constant *Evaluator::ComputeLoadResult(Constant *P) {
break;
// Handle a constantexpr bitcast.
case Instruction::BitCast:
if (auto *I = getInitializer(CE->getOperand(0)))
Constant *Val = getVal(CE->getOperand(0));
auto MM = MutatedMemory.find(Val);
auto *I = (MM != MutatedMemory.end()) ? MM->second
: getInitializer(CE->getOperand(0));
if (I)
return ConstantFoldLoadThroughBitcast(
I, P->getType()->getPointerElementType(), DL);
break;

62
llvm/test/Transforms/GlobalOpt/static-const-bitcast.ll Normal file
View File

@ -0,0 +1,62 @@
; RUN: opt -globalopt %s -S -o - | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%struct.A = type { %class.Wrapper }
%class.Wrapper = type { i32 }
$Wrapper = comdat any
@kA = internal global %struct.A zeroinitializer, align 4
; CHECK: @kA = internal unnamed_addr constant %struct.A { %class.Wrapper { i32 1036831949 } }, align 4
@llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } {
i32 65535, void ()* @_GLOBAL__sub_I_const_static.cc, i8* null }]
define dso_local i32 @AsBits(float* %x) #0 {
entry:
%0 = bitcast float* %x to i32*
%1 = load i32, i32* %0, align 4
ret i32 %1
}
define internal void @__cxx_global_var_init() #1 section ".text.startup" {
entry:
call void @Wrapper(%class.Wrapper* getelementptr inbounds (%struct.A, %struct.A* @kA, i32 0, i32 0), float 0x3FB99999A0000000)
%0 = call {}* @llvm.invariant.start.p0i8(i64 4, i8* bitcast (%struct.A* @kA to i8*))
ret void
}
define linkonce_odr dso_local void @Wrapper(%class.Wrapper* %this, float %x) unnamed_addr #0 comdat align 2 {
entry:
%x.addr = alloca float, align 4
store float %x, float* %x.addr, align 4
%store_ = getelementptr inbounds %class.Wrapper, %class.Wrapper* %this, i32 0, i32 0
%call = call i32 @AsBits(float* %x.addr)
store i32 %call, i32* %store_, align 4
ret void
}
declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) #2
; Function Attrs: nounwind uwtable
define dso_local void @LoadIt(%struct.A* %c) #0 {
entry:
%0 = bitcast %struct.A* %c to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %0, i8* align 4 bitcast (%struct.A* @kA to i8*), i64 4, i1 false)
ret void
}
; Function Attrs: argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i1) #2
; Function Attrs: uwtable
define internal void @_GLOBAL__sub_I_const_static.cc() #1 section ".text.startup" {
entry:
call void @__cxx_global_var_init()
ret void
}
attributes #0 = { nounwind uwtable "target-cpu"="x86-64" }
attributes #1 = { uwtable "target-cpu"="x86-64" }
attributes #2 = { argmemonly nounwind }