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[AIX] Add traceback ssp canary bit support

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We will need to set the ssp canary bit in traceback table to communicate
with unwinder about the canary.

Reviewed By: #powerpc, shchenz

Differential Revision: https://reviews.llvm.org/D103202
This commit is contained in:
Jinsong Ji 2021-06-10 02:39:57 +00:00
parent 55528042c5
commit 34315a15e8
4 changed files with 56 additions and 0 deletions
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1
include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
View File

@ -229,6 +229,7 @@ public:
~TargetLoweringObjectFileXCOFF() override = default;
static bool ShouldEmitEHBlock(const MachineFunction *MF);
static bool ShouldSetSSPCanaryBitInTB(const MachineFunction *MF);
static MCSymbol *getEHInfoTableSymbol(const MachineFunction *MF);

11
lib/CodeGen/TargetLoweringObjectFileImpl.cpp
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@ -2188,6 +2188,17 @@ bool TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(
return true;
}
bool TargetLoweringObjectFileXCOFF::ShouldSetSSPCanaryBitInTB(
const MachineFunction *MF) {
const Function &F = MF->getFunction();
if (!F.hasStackProtectorFnAttr())
return false;
// FIXME: check presence of canary word
// There are cases that the stack protectors are not really inserted even if
// the attributes are on.
return true;
}
MCSymbol *
TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(const MachineFunction *MF) {
return MF->getMMI().getContext().getOrCreateSymbol(

7
lib/Target/PowerPC/PPCAsmPrinter.cpp
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@ -78,6 +78,10 @@ using namespace llvm::XCOFF;
#define DEBUG_TYPE "asmprinter"
static cl::opt<bool> EnableSSPCanaryBitInTB(
"aix-ssp-tb-bit", cl::init(false),
cl::desc("Enable Passing SSP Canary info in Trackback on AIX"), cl::Hidden);
// Specialize DenseMapInfo to allow
// std::pair<const MCSymbol *, MCSymbolRefExpr::VariantKind> in DenseMap.
// This specialization is needed here because that type is used as keys in the
@ -2120,6 +2124,9 @@ void PPCAIXAsmPrinter::emitTracebackTable() {
if (SecondHalfOfMandatoryField & TracebackTable::HasExtensionTableMask) {
if (ShouldEmitEHBlock)
ExtensionTableFlag |= ExtendedTBTableFlag::TB_EH_INFO;
if (EnableSSPCanaryBitInTB &&
TargetLoweringObjectFileXCOFF::ShouldSetSSPCanaryBitInTB(MF))
ExtensionTableFlag |= ExtendedTBTableFlag::TB_SSP_CANARY;
CommentOS << "ExtensionTableFlag = "
<< getExtendedTBTableFlagString(ExtensionTableFlag);

37
test/CodeGen/PowerPC/aix-emit-tracebacktable-ssp.ll Normal file
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@ -0,0 +1,37 @@
; RUN: llc -aix-ssp-tb-bit -mtriple=powerpc64-ibm-aix-xcoff -O0 < %s | FileCheck %s
; CHECK-LABEL: f:
; CHECK: __ssp_canary_word
; CHECK: TB_SSP_CANARY
define i32 @f() #0 personality i8* bitcast (i32 (...)* @__xlcxx_personality_v1 to i8*) {
invoke i32 undef(i8* undef)
to label %invoke unwind label %lpad
invoke:
%var = alloca i32, align 4
store i32 0, i32* %var, align 4
%gep = getelementptr inbounds i32, i32* %var, i32 1
%ret = load i32, i32* %gep, align 4
ret i32 %ret
lpad:
landingpad { i8*, i32 }
catch i8* null
unreachable
}
; CHECK-LABEL: f2:
; CHECK: __ssp_canary_word
; Not emitting traceback bit when no unwinding needed.
; CHECK-NOT: TB_SSP_CANARY
define i32 @f2() #0 {
%var = alloca i32, align 4
store i32 0, i32* %var, align 4
%gep = getelementptr inbounds i32, i32* %var, i32 1
%ret = load i32, i32* %gep, align 4
ret i32 %ret
}
declare i32 @__xlcxx_personality_v1(...)
attributes #0 = { sspstrong }