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[SLH] Fix a nasty bug in SLH. 

Whenever we effectively take the address of a basic block we need to
manually update that basic block to reflect that fact or later passes
such as tail duplication and tail merging can break the invariants of
the code. =/ Sadly, there doesn't appear to be any good way of
automating this or even writing a reasonable assert to catch it early.

The change seems trivially and obviously correct, but sadly the only
really good test case I have is 1000s of basic blocks. I've tried
directly writing a test case that happens to make tail duplication do
something that crashes later on, but this appears to require an
*amazingly* complex set of conditions that I've not yet reproduced.

The change is technically covered by the tests because we mark the
blocks as having their address taken, but that doesn't really count as
properly testing the functionality.

llvm-svn: 348374
This commit is contained in:
Chandler Carruth 2018-12-05 15:42:11 +00:00
parent e3ea164659
commit 71c14a36a2
2 changed files with 51 additions and 25 deletions
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4
llvm/lib/Target/X86/X86SpeculativeLoadHardening.cpp
View File

@ -1141,7 +1141,9 @@ X86SpeculativeLoadHardeningPass::tracePredStateThroughIndirectBranches(
unsigned TargetReg = TargetAddrSSA.GetValueInMiddleOfBlock(&MBB);
// Insert a comparison of the incoming target register with this block's
// address.
// address. This also requires us to mark the block as having its address
// taken explicitly.
MBB.setHasAddressTaken();
auto InsertPt = MBB.SkipPHIsLabelsAndDebug(MBB.begin());
if (MF.getTarget().getCodeModel() == CodeModel::Small &&
!Subtarget->isPositionIndependent()) {

72
llvm/test/CodeGen/X86/speculative-load-hardening-indirect.ll
View File

@ -248,28 +248,32 @@ define i32 @test_indirectbr(i8** %ptr) nounwind {
; X64-NEXT: movq (%rdi), %rdx
; X64-NEXT: orq %rcx, %rdx
; X64-NEXT: jmpq *%rdx
; X64-NEXT: .LBB4_1: # %bb0
; X64-NEXT: .LBB4_1: # Block address taken
; X64-NEXT: # %bb0
; X64-NEXT: cmpq $.LBB4_1, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
; X64-NEXT: movl $2, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB4_3: # %bb2
; X64-NEXT: .LBB4_3: # Block address taken
; X64-NEXT: # %bb2
; X64-NEXT: cmpq $.LBB4_3, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
; X64-NEXT: movl $13, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB4_4: # %bb3
; X64-NEXT: .LBB4_4: # Block address taken
; X64-NEXT: # %bb3
; X64-NEXT: cmpq $.LBB4_4, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
; X64-NEXT: movl $42, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB4_2: # %bb1
; X64-NEXT: .LBB4_2: # Block address taken
; X64-NEXT: # %bb1
; X64-NEXT: cmpq $.LBB4_2, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
@ -285,7 +289,8 @@ define i32 @test_indirectbr(i8** %ptr) nounwind {
; X64-PIC-NEXT: movq (%rdi), %rdx
; X64-PIC-NEXT: orq %rcx, %rdx
; X64-PIC-NEXT: jmpq *%rdx
; X64-PIC-NEXT: .LBB4_1: # %bb0
; X64-PIC-NEXT: .LBB4_1: # Block address taken
; X64-PIC-NEXT: # %bb0
; X64-PIC-NEXT: leaq .LBB4_1(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -293,7 +298,8 @@ define i32 @test_indirectbr(i8** %ptr) nounwind {
; X64-PIC-NEXT: movl $2, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB4_3: # %bb2
; X64-PIC-NEXT: .LBB4_3: # Block address taken
; X64-PIC-NEXT: # %bb2
; X64-PIC-NEXT: leaq .LBB4_3(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -301,7 +307,8 @@ define i32 @test_indirectbr(i8** %ptr) nounwind {
; X64-PIC-NEXT: movl $13, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB4_4: # %bb3
; X64-PIC-NEXT: .LBB4_4: # Block address taken
; X64-PIC-NEXT: # %bb3
; X64-PIC-NEXT: leaq .LBB4_4(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -309,7 +316,8 @@ define i32 @test_indirectbr(i8** %ptr) nounwind {
; X64-PIC-NEXT: movl $42, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB4_2: # %bb1
; X64-PIC-NEXT: .LBB4_2: # Block address taken
; X64-PIC-NEXT: # %bb1
; X64-PIC-NEXT: leaq .LBB4_2(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -507,7 +515,8 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-NEXT: movq .LJTI6_0(,%rdx,8), %rdx
; X64-NEXT: orq %rcx, %rdx
; X64-NEXT: jmpq *%rdx
; X64-NEXT: .LBB6_3: # %bb1
; X64-NEXT: .LBB6_3: # Block address taken
; X64-NEXT: # %bb1
; X64-NEXT: cmpq $.LBB6_3, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
@ -520,21 +529,24 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-NEXT: movl $2, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB6_4: # %bb2
; X64-NEXT: .LBB6_4: # Block address taken
; X64-NEXT: # %bb2
; X64-NEXT: cmpq $.LBB6_4, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
; X64-NEXT: movl $13, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB6_5: # %bb3
; X64-NEXT: .LBB6_5: # Block address taken
; X64-NEXT: # %bb3
; X64-NEXT: cmpq $.LBB6_5, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
; X64-NEXT: movl $42, %eax
; X64-NEXT: orq %rcx, %rsp
; X64-NEXT: retq
; X64-NEXT: .LBB6_6: # %bb5
; X64-NEXT: .LBB6_6: # Block address taken
; X64-NEXT: # %bb5
; X64-NEXT: cmpq $.LBB6_6, %rdx
; X64-NEXT: cmovneq %rax, %rcx
; X64-NEXT: shlq $47, %rcx
@ -557,7 +569,8 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-PIC-NEXT: addq %rsi, %rdx
; X64-PIC-NEXT: orq %rcx, %rdx
; X64-PIC-NEXT: jmpq *%rdx
; X64-PIC-NEXT: .LBB6_3: # %bb1
; X64-PIC-NEXT: .LBB6_3: # Block address taken
; X64-PIC-NEXT: # %bb1
; X64-PIC-NEXT: leaq .LBB6_3(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -571,7 +584,8 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-PIC-NEXT: movl $2, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB6_4: # %bb2
; X64-PIC-NEXT: .LBB6_4: # Block address taken
; X64-PIC-NEXT: # %bb2
; X64-PIC-NEXT: leaq .LBB6_4(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -579,7 +593,8 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-PIC-NEXT: movl $13, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB6_5: # %bb3
; X64-PIC-NEXT: .LBB6_5: # Block address taken
; X64-PIC-NEXT: # %bb3
; X64-PIC-NEXT: leaq .LBB6_5(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -587,7 +602,8 @@ define i32 @test_switch_jumptable(i32 %idx) nounwind {
; X64-PIC-NEXT: movl $42, %eax
; X64-PIC-NEXT: orq %rcx, %rsp
; X64-PIC-NEXT: retq
; X64-PIC-NEXT: .LBB6_6: # %bb5
; X64-PIC-NEXT: .LBB6_6: # Block address taken
; X64-PIC-NEXT: # %bb5
; X64-PIC-NEXT: leaq .LBB6_6(%rip), %rsi
; X64-PIC-NEXT: cmpq %rsi, %rdx
; X64-PIC-NEXT: cmovneq %rax, %rcx
@ -697,25 +713,29 @@ define i32 @test_switch_jumptable_fallthrough(i32 %idx, i32* %a.ptr, i32* %b.ptr
; X64-NEXT: movl (%rsi), %eax
; X64-NEXT: orl %r9d, %eax
; X64-NEXT: movq $.LBB7_3, %rsi
; X64-NEXT: .LBB7_3: # %bb1
; X64-NEXT: .LBB7_3: # Block address taken
; X64-NEXT: # %bb1
; X64-NEXT: cmpq $.LBB7_3, %rsi
; X64-NEXT: cmovneq %r10, %r9
; X64-NEXT: addl (%rdx), %eax
; X64-NEXT: orl %r9d, %eax
; X64-NEXT: movq $.LBB7_4, %rsi
; X64-NEXT: .LBB7_4: # %bb2
; X64-NEXT: .LBB7_4: # Block address taken
; X64-NEXT: # %bb2
; X64-NEXT: cmpq $.LBB7_4, %rsi
; X64-NEXT: cmovneq %r10, %r9
; X64-NEXT: addl (%rcx), %eax
; X64-NEXT: orl %r9d, %eax
; X64-NEXT: movq $.LBB7_5, %rsi
; X64-NEXT: .LBB7_5: # %bb3
; X64-NEXT: .LBB7_5: # Block address taken
; X64-NEXT: # %bb3
; X64-NEXT: cmpq $.LBB7_5, %rsi
; X64-NEXT: cmovneq %r10, %r9
; X64-NEXT: addl (%r8), %eax
; X64-NEXT: orl %r9d, %eax
; X64-NEXT: movq $.LBB7_6, %rsi
; X64-NEXT: .LBB7_6: # %bb4
; X64-NEXT: .LBB7_6: # Block address taken
; X64-NEXT: # %bb4
; X64-NEXT: cmpq $.LBB7_6, %rsi
; X64-NEXT: cmovneq %r10, %r9
; X64-NEXT: shlq $47, %r9
@ -743,28 +763,32 @@ define i32 @test_switch_jumptable_fallthrough(i32 %idx, i32* %a.ptr, i32* %b.ptr
; X64-PIC-NEXT: movl (%rsi), %eax
; X64-PIC-NEXT: orl %r9d, %eax
; X64-PIC-NEXT: leaq .LBB7_3(%rip), %rsi
; X64-PIC-NEXT: .LBB7_3: # %bb1
; X64-PIC-NEXT: .LBB7_3: # Block address taken
; X64-PIC-NEXT: # %bb1
; X64-PIC-NEXT: leaq .LBB7_3(%rip), %rdi
; X64-PIC-NEXT: cmpq %rdi, %rsi
; X64-PIC-NEXT: cmovneq %r10, %r9
; X64-PIC-NEXT: addl (%rdx), %eax
; X64-PIC-NEXT: orl %r9d, %eax
; X64-PIC-NEXT: leaq .LBB7_4(%rip), %rsi
; X64-PIC-NEXT: .LBB7_4: # %bb2
; X64-PIC-NEXT: .LBB7_4: # Block address taken
; X64-PIC-NEXT: # %bb2
; X64-PIC-NEXT: leaq .LBB7_4(%rip), %rdx
; X64-PIC-NEXT: cmpq %rdx, %rsi
; X64-PIC-NEXT: cmovneq %r10, %r9
; X64-PIC-NEXT: addl (%rcx), %eax
; X64-PIC-NEXT: orl %r9d, %eax
; X64-PIC-NEXT: leaq .LBB7_5(%rip), %rsi
; X64-PIC-NEXT: .LBB7_5: # %bb3
; X64-PIC-NEXT: .LBB7_5: # Block address taken
; X64-PIC-NEXT: # %bb3
; X64-PIC-NEXT: leaq .LBB7_5(%rip), %rcx
; X64-PIC-NEXT: cmpq %rcx, %rsi
; X64-PIC-NEXT: cmovneq %r10, %r9
; X64-PIC-NEXT: addl (%r8), %eax
; X64-PIC-NEXT: orl %r9d, %eax
; X64-PIC-NEXT: leaq .LBB7_6(%rip), %rsi
; X64-PIC-NEXT: .LBB7_6: # %bb4
; X64-PIC-NEXT: .LBB7_6: # Block address taken
; X64-PIC-NEXT: # %bb4
; X64-PIC-NEXT: leaq .LBB7_6(%rip), %rcx
; X64-PIC-NEXT: cmpq %rcx, %rsi
; X64-PIC-NEXT: cmovneq %r10, %r9