[llvm] 11937ca - [RISC-V][HWASAN] Support tagging global variables for RISC-V HWASAN
Alexey Baturo via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 13 03:58:11 PST 2022
Author: Alexey Baturo
Date: 2022-12-13T14:57:34+03:00
New Revision: 11937ca5642216a67e021e69fc824f709267bada
URL: https://github.com/llvm/llvm-project/commit/11937ca5642216a67e021e69fc824f709267bada
DIFF: https://github.com/llvm/llvm-project/commit/11937ca5642216a67e021e69fc824f709267bada.diff
LOG: [RISC-V][HWASAN] Support tagging global variables for RISC-V HWASAN
Reviewed by: luismarques
Differential Revision: https://reviews.llvm.org/D132995
Added:
llvm/test/CodeGen/RISCV/tagged-globals.ll
Modified:
llvm/lib/Target/RISCV/RISCV.td
llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
llvm/lib/Target/RISCV/RISCVISelLowering.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
index cde63564e5c40..fd0dd8a759ca7 100644
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -525,6 +525,11 @@ def FeatureForcedAtomics : SubtargetFeature<
def HasAtomicLdSt
: Predicate<"Subtarget->hasStdExtA() || Subtarget->hasForcedAtomics()">;
+def FeatureTaggedGlobals : SubtargetFeature<"tagged-globals",
+ "AllowTaggedGlobals",
+ "true", "Use an instruction sequence for taking the address of a global "
+ "that allows a memory tag in the upper address bits">;
+
//===----------------------------------------------------------------------===//
// Named operands for CSR instructions.
//===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp b/llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
index 78fc58b69d8ad..70ae6eba4f8db 100644
--- a/llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
+++ b/llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp
@@ -333,8 +333,12 @@ bool RISCVPreRAExpandPseudo::expandLoadAddress(
MachineBasicBlock::iterator &NextMBBI) {
MachineFunction *MF = MBB.getParent();
- assert(MF->getTarget().isPositionIndependent());
const auto &STI = MF->getSubtarget<RISCVSubtarget>();
+ // When HWASAN is used and tagging of global variables is enabled
+ // they should be accessed via the GOT, since the tagged address of a global
+ // is incompatible with existing code models. This also applies to non-pic
+ // mode.
+ assert(MF->getTarget().isPositionIndependent() || STI.allowTaggedGlobals());
unsigned SecondOpcode = STI.is64Bit() ? RISCV::LD : RISCV::LW;
return expandAuipcInstPair(MBB, MBBI, NextMBBI, RISCVII::MO_GOT_HI,
SecondOpcode);
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 7efaefd00ba7d..4010dc88fe2d2 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -4230,9 +4230,13 @@ SDValue RISCVTargetLowering::getAddr(NodeTy *N, SelectionDAG &DAG,
SDLoc DL(N);
EVT Ty = getPointerTy(DAG.getDataLayout());
- if (isPositionIndependent()) {
+ // When HWASAN is used and tagging of global variables is enabled
+ // they should be accessed via the GOT, since the tagged address of a global
+ // is incompatible with existing code models. This also applies to non-pic
+ // mode.
+ if (isPositionIndependent() || Subtarget.allowTaggedGlobals()) {
SDValue Addr = getTargetNode(N, DL, Ty, DAG, 0);
- if (IsLocal)
+ if (IsLocal && !Subtarget.allowTaggedGlobals())
// Use PC-relative addressing to access the symbol. This generates the
// pattern (PseudoLLA sym), which expands to (addi (auipc %pcrel_hi(sym))
// %pcrel_lo(auipc)).
diff --git a/llvm/test/CodeGen/RISCV/tagged-globals.ll b/llvm/test/CodeGen/RISCV/tagged-globals.ll
new file mode 100644
index 0000000000000..21be791c366b0
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/tagged-globals.ll
@@ -0,0 +1,87 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --no-generate-body-for-unused-prefixes
+; RUN: llc --relocation-model=pic < %s | FileCheck %s
+; RUN: llc --relocation-model=static < %s | FileCheck %s
+
+ at global_ext = external global i32
+ at global_int = internal global i32 0
+declare void @func()
+
+define i32* @global_addr() #0 {
+; CHECK-LABEL: global_addr:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi0:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_ext)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi0)(a0)
+; CHECK-NEXT: ret
+ ret i32* @global_ext
+}
+
+define i32 @global_load() #0 {
+; CHECK-LABEL: global_load:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi1:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_ext)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi1)(a0)
+; CHECK-NEXT: lw a0, 0(a0)
+; CHECK-NEXT: ret
+ %load = load i32, i32* @global_ext
+ ret i32 %load
+}
+
+define void @global_store() #0 {
+; CHECK-LABEL: global_store:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi2:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_ext)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi2)(a0)
+; CHECK-NEXT: sw zero, 0(a0)
+; CHECK-NEXT: ret
+ store i32 0, i32* @global_ext
+ ret void
+}
+
+define i32* @global_int_addr() #0 {
+; CHECK-LABEL: global_int_addr:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi3:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_int)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi3)(a0)
+; CHECK-NEXT: ret
+ ret i32* @global_int
+}
+
+define i32 @global_int_load() #0 {
+; CHECK-LABEL: global_int_load:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi4:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_int)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi4)(a0)
+; CHECK-NEXT: lw a0, 0(a0)
+; CHECK-NEXT: ret
+ %load = load i32, i32* @global_int
+ ret i32 %load
+}
+
+define void @global_int_store() #0 {
+; CHECK-LABEL: global_int_store:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi5:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(global_int)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi5)(a0)
+; CHECK-NEXT: sw zero, 0(a0)
+; CHECK-NEXT: ret
+ store i32 0, i32* @global_int
+ ret void
+}
+
+define void ()* @func_addr() #0 {
+; CHECK-LABEL: func_addr:
+; CHECK: # %bb.0:
+; CHECK-NEXT: .Lpcrel_hi6:
+; CHECK-NEXT: auipc a0, %got_pcrel_hi(func)
+; CHECK-NEXT: ld a0, %pcrel_lo(.Lpcrel_hi6)(a0)
+; CHECK-NEXT: ret
+ ret void ()* @func
+}
+
+attributes #0 = { "target-features"="+tagged-globals" }
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