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

[ConstantInt] Check active bits before calling getZExtValue. 

Without this check, we hit an assertion in getZExtValue, if the constant
value does not fit into an uint64_t.

As getZExtValue returns an uint64_t, should we update
getAggregateElement to take an uin64_t as well?

This fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6109.

Reviewers: efriedma, craig.topper, spatel

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D55547

llvm-svn: 348906
This commit is contained in:
Florian Hahn 2018-12-12 02:22:12 +00:00
parent 8272a71285
commit cc419ad7df
3 changed files with 23 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
llvm/include/llvm/IR/Constant.h
View File

@ -114,7 +114,8 @@ public:
/// For aggregates (struct/array/vector) return the constant that corresponds
/// to the specified element if possible, or null if not. This can return null
/// if the element index is a ConstantExpr, or if 'this' is a constant expr.
/// if the element index is a ConstantExpr, if 'this' is a constant expr or
/// if the constant does not fit into an uint64_t.
Constant *getAggregateElement(unsigned Elt) const;
Constant *getAggregateElement(Constant *Elt) const;

6
llvm/lib/IR/Constants.cpp
View File

@ -350,8 +350,12 @@ Constant *Constant::getAggregateElement(unsigned Elt) const {
Constant *Constant::getAggregateElement(Constant *Elt) const {
assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt))
if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt)) {
// Check if the constant fits into an uint64_t.
if (CI->getValue().getActiveBits() > 64)
return nullptr;
return getAggregateElement(CI->getZExtValue());
}
return nullptr;
}

20
llvm/test/Transforms/SCCP/apint-bigint2.ll
View File

@ -1,11 +1,11 @@
; RUN: opt < %s -sccp -S | not grep load
; RUN: opt < %s -sccp -S | FileCheck %s
@Y = constant [6 x i101] [ i101 12, i101 123456789000000, i101 -12,
i101 -123456789000000, i101 0,i101 9123456789000000]
define i101 @array()
{
Head:
; CHECK-LABEL: @array
; CHECK-NEXT: ret i101 123456789000000
define i101 @array() {
%A = getelementptr [6 x i101], [6 x i101]* @Y, i32 0, i32 1
%B = load i101, i101* %A
%D = and i101 %B, 1
@ -16,3 +16,15 @@ Head:
ret i101 %G
}
; CHECK-LABEL: @large_aggregate
; CHECK-NEXT: ret i101 undef
define i101 @large_aggregate() {
%B = load i101, i101* undef
%D = and i101 %B, 1
%DD = or i101 %D, 1
%F = getelementptr [6 x i101], [6 x i101]* @Y, i32 0, i32 5
%G = getelementptr i101, i101* %F, i101 %DD
%L3 = load i101, i101* %G
ret i101 %L3
}