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llvm-mirror/test/Transforms/Inline/devirtualize.ll
Nick Desaulniers 5d27c8ae50 [Inline] prevent inlining on stack protector mismatch 
It's common for code that manipulates the stack via inline assembly or
that has to set up its own stack canary (such as the Linux kernel) would
like to avoid stack protectors in certain functions. In this case, we've
been bitten by numerous bugs where a callee with a stack protector is
inlined into an attribute((no_stack_protector)) caller, which
generally breaks the caller's assumptions about not having a stack
protector. LTO exacerbates the issue.

While developers can avoid this by putting all no_stack_protector
functions in one translation unit together and compiling those with
-fno-stack-protector, it's generally not very ergonomic or as
ergonomic as a function attribute, and still doesn't work for LTO. See also:
https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/
https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u

SSP attributes can be ordered by strength. Weakest to strongest, they
are: ssp, sspstrong, sspreq.  Callees with differing SSP attributes may be
inlined into each other, and the strongest attribute will be applied to the
caller. (No change)

After this change:
* A callee with no SSP attributes will no longer be inlined into a
  caller with SSP attributes.
* The reverse is also true: a callee with an SSP attribute will not be
  inlined into a caller with no SSP attributes.
* The alwaysinline attribute overrides these rules.

Functions that get synthesized by the compiler may not get inlined as a
result if they are not created with the same stack protector function
attribute as their callers.

Alternative approach to https://reviews.llvm.org/D87956.

Fixes pr/47479.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed By: rnk, MaskRay

Differential Revision: https://reviews.llvm.org/D91816
2020-12-02 11:00:16 -08:00

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; RUN: opt -S -Os < %s | FileCheck %s
; RUN: opt -S -aa-pipeline=basic-aa -passes='default<Os>' < %s | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin10.0.0"
; Simple devirt testcase, requires iteration between inliner and GVN.
; rdar://6295824
define i32 @foo(i32 ()** noalias %p, i64* noalias %q) nounwind ssp {
entry:
store i32 ()* @bar, i32 ()** %p
store i64 0, i64* %q
%tmp3 = load i32 ()*, i32 ()** %p ; <i32 ()*> [#uses=1]
%call = call i32 %tmp3() ; <i32> [#uses=1]
%X = add i32 %call, 4
ret i32 %X
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
; CHECK-NEXT: store
; CHECK-NEXT: store
; CHECK-NEXT: ret i32 11
}
define internal i32 @bar() nounwind ssp {
entry:
ret i32 7
}
;; More complex devirt case, from PR6724
; CHECK: @_Z1gv()
; CHECK-NEXT: entry:
; CHECK-NEXT: ret i32 7
%0 = type { i8*, i8* }
%1 = type { i8*, i8*, i32, i32, i8*, i64, i8*, i64 }
%2 = type { i8*, i8*, i8* }
%struct.A = type { i8** }
%struct.B = type { i8** }
%struct.C = type { [16 x i8] }
%struct.D = type { [16 x i8] }
@_ZTV1D = linkonce_odr constant [6 x i8*] [i8* null, i8* bitcast (%2* @_ZTI1D to i8*), i8* bitcast (i32 (%struct.C*)* @_ZN1D1fEv to i8*), i8* inttoptr (i64 -8 to i8*), i8* bitcast (%2* @_ZTI1D to i8*), i8* bitcast (i32 (%struct.C*)* @_ZThn8_N1D1fEv to i8*)] ; <[6 x i8*]*> [#uses=2]
@_ZTVN10__cxxabiv120__si_class_type_infoE = external global i8* ; <i8**> [#uses=1]
@_ZTS1D = linkonce_odr constant [3 x i8] c"1D\00" ; <[3 x i8]*> [#uses=1]
@_ZTVN10__cxxabiv121__vmi_class_type_infoE = external global i8* ; <i8**> [#uses=1]
@_ZTS1C = linkonce_odr constant [3 x i8] c"1C\00" ; <[3 x i8]*> [#uses=1]
@_ZTVN10__cxxabiv117__class_type_infoE = external global i8* ; <i8**> [#uses=1]
@_ZTS1A = linkonce_odr constant [3 x i8] c"1A\00" ; <[3 x i8]*> [#uses=1]
@_ZTI1A = linkonce_odr constant %0 { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1A, i32 0, i32 0) } ; <%0*> [#uses=1]
@_ZTS1B = linkonce_odr constant [3 x i8] c"1B\00" ; <[3 x i8]*> [#uses=1]
@_ZTI1B = linkonce_odr constant %0 { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1B, i32 0, i32 0) } ; <%0*> [#uses=1]
@_ZTI1C = linkonce_odr constant %1 { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv121__vmi_class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1C, i32 0, i32 0), i32 0, i32 2, i8* bitcast (%0* @_ZTI1A to i8*), i64 2, i8* bitcast (%0* @_ZTI1B to i8*), i64 2050 } ; <%1*> [#uses=1]
@_ZTI1D = linkonce_odr constant %2 { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv120__si_class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1D, i32 0, i32 0), i8* bitcast (%1* @_ZTI1C to i8*) } ; <%2*> [#uses=1]
@_ZTV1C = linkonce_odr constant [6 x i8*] [i8* null, i8* bitcast (%1* @_ZTI1C to i8*), i8* bitcast (i32 (%struct.C*)* @_ZN1C1fEv to i8*), i8* inttoptr (i64 -8 to i8*), i8* bitcast (%1* @_ZTI1C to i8*), i8* bitcast (i32 (%struct.C*)* @_ZThn8_N1C1fEv to i8*)] ; <[6 x i8*]*> [#uses=2]
@_ZTV1B = linkonce_odr constant [3 x i8*] [i8* null, i8* bitcast (%0* @_ZTI1B to i8*), i8* bitcast (i32 (%struct.A*)* @_ZN1B1fEv to i8*)] ; <[3 x i8*]*> [#uses=1]
@_ZTV1A = linkonce_odr constant [3 x i8*] [i8* null, i8* bitcast (%0* @_ZTI1A to i8*), i8* bitcast (i32 (%struct.A*)* @_ZN1A1fEv to i8*)] ; <[3 x i8*]*> [#uses=1]
define i32 @_Z1gv() ssp {
entry:
%d = alloca %struct.C, align 8 ; <%struct.C*> [#uses=2]
call void @_ZN1DC1Ev(%struct.C* %d)
%call = call i32 @_Z1fP1D(%struct.C* %d) ; <i32> [#uses=1]
%X = add i32 %call, 3
ret i32 %X
}
define linkonce_odr void @_ZN1DC1Ev(%struct.C* %this) inlinehint ssp align 2 {
entry:
call void @_ZN1DC2Ev(%struct.C* %this)
ret void
}
define internal i32 @_Z1fP1D(%struct.C* %d) ssp {
entry:
%0 = icmp eq %struct.C* %d, null ; <i1> [#uses=1]
br i1 %0, label %cast.end, label %cast.notnull
cast.notnull: ; preds = %entry
%1 = bitcast %struct.C* %d to i8* ; <i8*> [#uses=1]
%add.ptr = getelementptr i8, i8* %1, i64 8 ; <i8*> [#uses=1]
%2 = bitcast i8* %add.ptr to %struct.A* ; <%struct.A*> [#uses=1]
br label %cast.end
cast.end: ; preds = %entry, %cast.notnull
%3 = phi %struct.A* [ %2, %cast.notnull ], [ null, %entry ] ; <%struct.A*> [#uses=2]
%4 = bitcast %struct.A* %3 to i32 (%struct.A*)*** ; <i32 (%struct.A*)***> [#uses=1]
%5 = load i32 (%struct.A*)**, i32 (%struct.A*)*** %4 ; <i32 (%struct.A*)**> [#uses=1]
%vfn = getelementptr inbounds i32 (%struct.A*)*, i32 (%struct.A*)** %5, i64 0 ; <i32 (%struct.A*)**> [#uses=1]
%6 = load i32 (%struct.A*)*, i32 (%struct.A*)** %vfn ; <i32 (%struct.A*)*> [#uses=1]
%call = call i32 %6(%struct.A* %3) ; <i32> [#uses=1]
ret i32 %call
}
define linkonce_odr i32 @_ZN1D1fEv(%struct.C* %this) ssp align 2 {
entry:
ret i32 4
}
define linkonce_odr i32 @_ZThn8_N1D1fEv(%struct.C* %this) ssp {
entry:
%0 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%1 = getelementptr inbounds i8, i8* %0, i64 -8 ; <i8*> [#uses=1]
%2 = bitcast i8* %1 to %struct.C* ; <%struct.C*> [#uses=1]
%call = call i32 @_ZN1D1fEv(%struct.C* %2) ; <i32> [#uses=1]
ret i32 %call
}
define linkonce_odr void @_ZN1DC2Ev(%struct.C* %this) inlinehint ssp align 2 {
entry:
call void @_ZN1CC2Ev(%struct.C* %this)
%0 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%1 = getelementptr inbounds i8, i8* %0, i64 0 ; <i8*> [#uses=1]
%2 = bitcast i8* %1 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([6 x i8*], [6 x i8*]* @_ZTV1D, i64 0, i64 2), i8*** %2
%3 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%4 = getelementptr inbounds i8, i8* %3, i64 8 ; <i8*> [#uses=1]
%5 = bitcast i8* %4 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([6 x i8*], [6 x i8*]* @_ZTV1D, i64 0, i64 5), i8*** %5
ret void
}
define linkonce_odr void @_ZN1CC2Ev(%struct.C* %this) inlinehint ssp align 2 {
entry:
%0 = bitcast %struct.C* %this to %struct.A* ; <%struct.A*> [#uses=1]
call void @_ZN1AC2Ev(%struct.A* %0)
%1 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%2 = getelementptr inbounds i8, i8* %1, i64 8 ; <i8*> [#uses=1]
%3 = bitcast i8* %2 to %struct.A* ; <%struct.A*> [#uses=1]
call void @_ZN1BC2Ev(%struct.A* %3)
%4 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%5 = getelementptr inbounds i8, i8* %4, i64 0 ; <i8*> [#uses=1]
%6 = bitcast i8* %5 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([6 x i8*], [6 x i8*]* @_ZTV1C, i64 0, i64 2), i8*** %6
%7 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%8 = getelementptr inbounds i8, i8* %7, i64 8 ; <i8*> [#uses=1]
%9 = bitcast i8* %8 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([6 x i8*], [6 x i8*]* @_ZTV1C, i64 0, i64 5), i8*** %9
ret void
}
define linkonce_odr i32 @_ZN1C1fEv(%struct.C* %this) ssp align 2 {
entry:
ret i32 3
}
define linkonce_odr i32 @_ZThn8_N1C1fEv(%struct.C* %this) {
entry:
%0 = bitcast %struct.C* %this to i8* ; <i8*> [#uses=1]
%1 = getelementptr inbounds i8, i8* %0, i64 -8 ; <i8*> [#uses=1]
%2 = bitcast i8* %1 to %struct.C* ; <%struct.C*> [#uses=1]
%call = call i32 @_ZN1C1fEv(%struct.C* %2) ; <i32> [#uses=1]
ret i32 %call
}
define linkonce_odr void @_ZN1AC2Ev(%struct.A* %this) inlinehint ssp align 2 {
entry:
%0 = bitcast %struct.A* %this to i8* ; <i8*> [#uses=1]
%1 = getelementptr inbounds i8, i8* %0, i64 0 ; <i8*> [#uses=1]
%2 = bitcast i8* %1 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([3 x i8*], [3 x i8*]* @_ZTV1A, i64 0, i64 2), i8*** %2
ret void
}
define linkonce_odr void @_ZN1BC2Ev(%struct.A* %this) inlinehint ssp align 2 {
entry:
%0 = bitcast %struct.A* %this to i8* ; <i8*> [#uses=1]
%1 = getelementptr inbounds i8, i8* %0, i64 0 ; <i8*> [#uses=1]
%2 = bitcast i8* %1 to i8*** ; <i8***> [#uses=1]
store i8** getelementptr inbounds ([3 x i8*], [3 x i8*]* @_ZTV1B, i64 0, i64 2), i8*** %2
ret void
}
define linkonce_odr i32 @_ZN1B1fEv(%struct.A* %this) ssp align 2 {
entry:
ret i32 2
}
define linkonce_odr i32 @_ZN1A1fEv(%struct.A* %this) ssp align 2 {
entry:
ret i32 1
}
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