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Differential D14763

Disable gvn non-local speculative loads under asan.
ClosedPublic

Authored by aizatsky on Nov 17 2015, 4:43 PM.

Details

Reviewers
kcc
Commits
rGc7810baaa676: Disable gvn non-local speculative loads under asan.
rL253498: Disable gvn non-local speculative loads under asan.
Summary

Fix for https://llvm.org/bugs/show_bug.cgi?id=25550

Diff Detail

Repository
rL LLVM

Event Timeline

aizatsky updated this revision to Diff 40454.Nov 17 2015, 4:43 PM
aizatsky updated this revision to Diff 40456.
aizatsky retitled this revision from to Disable gvn non-local speculative loads under asan..
aizatsky updated this object.

format

aizatsky updated this revision to Diff 40457.Nov 17 2015, 4:46 PM

nit

aizatsky added a reviewer: kcc.Nov 17 2015, 4:46 PM
aizatsky added a subscriber: llvm-commits.
kcc accepted this revision.Nov 17 2015, 5:04 PM
kcc edited edge metadata.

LGTM.
Please also check if this affects tsan, and if so please fix separately

This revision is now accepted and ready to land.Nov 17 2015, 5:04 PM
Closed by commit rL253498: Disable gvn non-local speculative loads under asan. (authored by aizatsky). · Explain WhyNov 18 2015, 12:45 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
trunk/
lib/
Transforms/
Scalar/
4 lines
test/
Transforms/
GVN/
57 lines

Diff 40541

llvm/trunk/lib/Transforms/Scalar/GVN.cpp

Show First 20 Lines • Show All 1,695 Lines • ▼ Show 20 Linesbool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
markInstructionForDeletion(LI); markInstructionForDeletion(LI);
++NumPRELoad; ++NumPRELoad;
return true; return true;
} }
/// Attempt to eliminate a load whose dependencies are /// Attempt to eliminate a load whose dependencies are
/// non-local by performing PHI construction. /// non-local by performing PHI construction.
bool GVN::processNonLocalLoad(LoadInst *LI) { bool GVN::processNonLocalLoad(LoadInst *LI) {
// non-local speculations are not allowed under asan.
if (LI->getParent()->getParent()->hasFnAttribute(Attribute::SanitizeAddress))
return false;
// Step 1: Find the non-local dependencies of the load. // Step 1: Find the non-local dependencies of the load.
LoadDepVect Deps; LoadDepVect Deps;
MD->getNonLocalPointerDependency(LI, Deps); MD->getNonLocalPointerDependency(LI, Deps);
// If we had to process more than one hundred blocks to find the // If we had to process more than one hundred blocks to find the
// dependencies, this load isn't worth worrying about. Optimizing // dependencies, this load isn't worth worrying about. Optimizing
// it will be too expensive. // it will be too expensive.
unsigned NumDeps = Deps.size(); unsigned NumDeps = Deps.size();
▲ Show 20 Lines • Show All 1,212 Lines • Show Last 20 Lines

llvm/trunk/test/Transforms/GVN/no_speculative_loads_with_asan.ll

; RUN: opt -O3 -S %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
declare noalias i8* @_Znam(i64) #1
define i32 @TestNoAsan() {
%1 = tail call noalias i8* @_Znam(i64 2)
%2 = getelementptr inbounds i8, i8* %1, i64 1
store i8 0, i8* %2, align 1
store i8 0, i8* %1, align 1
%3 = bitcast i8* %1 to i16*
%4 = load i16, i16* %3, align 4
%5 = icmp eq i16 %4, 0
br i1 %5, label %11, label %6
; <label>:6 ; preds = %0
%7 = getelementptr inbounds i8, i8* %1, i64 2
%8 = bitcast i8* %7 to i16*
%9 = load i16, i16* %8, align 2
%10 = sext i16 %9 to i32
br label %11
; <label>:11 ; preds = %0, %6
%12 = phi i32 [ %10, %6 ], [ 0, %0 ]
ret i32 %12
}
; CHECK-LABEL: @TestNoAsan
; CHECK: %[[LOAD:[^ ]+]] = load i32
; CHECK: {{.*}} = ashr i32 %[[LOAD]]
; CHECK-NOT: {{.*}} = phi
define i32 @TestAsan() sanitize_address {
%1 = tail call noalias i8* @_Znam(i64 2)
%2 = getelementptr inbounds i8, i8* %1, i64 1
store i8 0, i8* %2, align 1
store i8 0, i8* %1, align 1
%3 = bitcast i8* %1 to i16*
%4 = load i16, i16* %3, align 4
%5 = icmp eq i16 %4, 0
br i1 %5, label %11, label %6
; <label>:6 ; preds = %0
%7 = getelementptr inbounds i8, i8* %1, i64 2
%8 = bitcast i8* %7 to i16*
%9 = load i16, i16* %8, align 2
%10 = sext i16 %9 to i32
br label %11
; <label>:11 ; preds = %0, %6
%12 = phi i32 [ %10, %6 ], [ 0, %0 ]
ret i32 %12
}
; CHECK-LABEL: @TestAsan
; CHECK-NOT: %[[LOAD:[^ ]+]] = load i32
; CHECK: {{.*}} = phi