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llvm-mirror/test/Instrumentation/AddressSanitizer/asan-vs-gvn.ll
Kostya Serebryany 2ae1ed1c8f [asan] Optimize accesses to global arrays with constant index
Summary:
Given a global array G[N], which is declared in this CU and has static initializer
avoid instrumenting accesses like G[i], where 'i' is a constant and 0<=i<N.
Also add a bit of stats.

This eliminates ~1% of instrumentations on SPEC2006
and also partially helps when asan is being run together with coverage.

Reviewers: samsonov

Reviewed By: samsonov

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1947

llvm-svn: 192794
2013-10-16 14:06:14 +00:00

57 lines
1.9 KiB
LLVM

; RUN: opt < %s -basicaa -gvn -asan -S | FileCheck %s
; ASAN conflicts with load widening iff the widened load accesses data out of bounds
; (while the original unwidened loads do not).
; http://code.google.com/p/address-sanitizer/issues/detail?id=20#c1
; 32-bit little endian target.
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
%struct_of_7_bytes_4_aligned = type { i32, i8, i8, i8}
@f = external global %struct_of_7_bytes_4_aligned , align 4
; Accessing bytes 4 and 6, not ok to widen to i32 if sanitize_address is set.
define i32 @test_widening_bad(i8* %P) nounwind ssp noredzone sanitize_address {
entry:
%tmp = load i8* getelementptr inbounds (%struct_of_7_bytes_4_aligned* @f, i64 0, i32 1), align 4
%conv = zext i8 %tmp to i32
%tmp1 = load i8* getelementptr inbounds (%struct_of_7_bytes_4_aligned* @f, i64 0, i32 3), align 1
%conv2 = zext i8 %tmp1 to i32
%add = add nsw i32 %conv, %conv2
ret i32 %add
; CHECK: @test_widening_bad
; CHECK: __asan_report_load1
; CHECK: __asan_report_load1
; CHECK-NOT: __asan_report
; We can not use check for "ret" here because __asan_report_load1 calls live after ret.
; CHECK: end_test_widening_bad
}
define void @end_test_widening_bad() {
entry:
ret void
}
;; Accessing bytes 4 and 5. Ok to widen to i16.
define i32 @test_widening_ok(i8* %P) nounwind ssp noredzone sanitize_address {
entry:
%tmp = load i8* getelementptr inbounds (%struct_of_7_bytes_4_aligned* @f, i64 0, i32 1), align 4
%conv = zext i8 %tmp to i32
%tmp1 = load i8* getelementptr inbounds (%struct_of_7_bytes_4_aligned* @f, i64 0, i32 2), align 1
%conv2 = zext i8 %tmp1 to i32
%add = add nsw i32 %conv, %conv2
ret i32 %add
; CHECK: @test_widening_ok
; CHECK: __asan_report_load2
; CHECK-NOT: __asan_report
; CHECK: end_test_widening_ok
}
define void @end_test_widening_ok() {
entry:
ret void
}