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llvm-project/llvm/test/Instrumentation/MemorySanitizer/pr32842.ll

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[msan] Fix PR32842 It turned out that MSan was incorrectly calculating the shadow for int comparisons: it was done by truncating the result of (Shadow1 OR Shadow2) to i1, effectively rendering all bits except LSB useless. This approach doesn't work e.g. in the case where the values being compared are even (i.e. have the LSB of the shadow equal to zero). Instead, if CreateShadowCast() has to cast a bigger int to i1, we replace the truncation with an ICMP to 0. This patch doesn't affect the code generated for SPEC 2006 binaries, i.e. there's no performance impact. For the test case reported in PR32842 MSan with the patch generates a slightly more efficient code: orq %rcx, %rax jne .LBB0_6 , instead of: orl %ecx, %eax testb $1, %al jne .LBB0_6 llvm-svn: 302787
2017-05-11 19:07:48 +08:00
; Regression test for https://bugs.llvm.org/show_bug.cgi?id=32842
;
[NewPM] Port Msan Summary: Keeping msan a function pass requires replacing the module level initialization: That means, don't define a ctor function which calls __msan_init, instead just declare the init function at the first access, and add that to the global ctors list. Changes: - Pull the actual sanitizer and the wrapper pass apart. - Add a newpm msan pass. The function pass inserts calls to runtime library functions, for which it inserts declarations as necessary. - Update tests. Caveats: - There is one test that I dropped, because it specifically tested the definition of the ctor. Reviewers: chandlerc, fedor.sergeev, leonardchan, vitalybuka Subscribers: sdardis, nemanjai, javed.absar, hiraditya, kbarton, bollu, atanasyan, jsji Differential Revision: https://reviews.llvm.org/D55647 llvm-svn: 350305
2019-01-03 21:42:44 +08:00
; RUN: opt < %s -S -passes=msan 2>&1 | FileCheck %s
[msan] Fix PR32842 It turned out that MSan was incorrectly calculating the shadow for int comparisons: it was done by truncating the result of (Shadow1 OR Shadow2) to i1, effectively rendering all bits except LSB useless. This approach doesn't work e.g. in the case where the values being compared are even (i.e. have the LSB of the shadow equal to zero). Instead, if CreateShadowCast() has to cast a bigger int to i1, we replace the truncation with an ICMP to 0. This patch doesn't affect the code generated for SPEC 2006 binaries, i.e. there's no performance impact. For the test case reported in PR32842 MSan with the patch generates a slightly more efficient code: orq %rcx, %rax jne .LBB0_6 , instead of: orl %ecx, %eax testb $1, %al jne .LBB0_6 llvm-svn: 302787
2017-05-11 19:07:48 +08:00
; RUN: opt < %s -msan -S | FileCheck %s
;target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define zeroext i1 @_Z1fii(i32 %x, i32 %y) sanitize_memory {
entry:
%cmp = icmp slt i32 %x, %y
ret i1 %cmp
}
; CHECK: [[X:[^ ]+]] = load{{.*}}__msan_param_tls{{.*}}
; CHECK: [[Y:[^ ]+]] = load{{.*}}__msan_param_tls{{.*}}
; CHECK: [[OR:[^ ]+]] = or i32 [[Y]], [[X]]
; Make sure the shadow of the (x < y) comparison isn't truncated to i1.
; CHECK-NOT: trunc i32 [[OR]] to i1
; CHECK: [[CMP:[^ ]+]] = icmp ne i32 [[OR]], 0
; CHECK: store i1 [[CMP]],{{.*}}__msan_retval_tls