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Fix ARM test breakage
paulkirth added a comment.
Actually fix the ARM test
Current stack size diagnostics ignore the size of the unsafe stack.
This patch attaches the size of the static portion of the unsafe stack
to the function as metadata, which can be used by the backend to emit
diagnostics regarding stack usage.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D119996
Files:
clang/test/Frontend/stack-usage-safestack.c
llvm/include/llvm/CodeGen/MachineFrameInfo.h
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/lib/CodeGen/MachineFunction.cpp
llvm/lib/CodeGen/PrologEpilogInserter.cpp
llvm/lib/CodeGen/SafeStack.cpp
llvm/test/Transforms/SafeStack/ARM/debug.ll
Index: llvm/test/Transforms/SafeStack/ARM/debug.ll
===================================================================
--- llvm/test/Transforms/SafeStack/ARM/debug.ll
+++ llvm/test/Transforms/SafeStack/ARM/debug.ll
@@ -10,8 +10,8 @@
; void Capture(char*x);
; void f() { char c[16]; Capture(c); }
-; CHECK: !35 = !DILocation(line: 3, column: 11, scope: !17, inlinedAt: !36)
-; CHECK: !36 = distinct !DILocation(line: 6, scope: !27)
+; CHECK: !36 = !DILocation(line: 3, column: 11, scope: !17, inlinedAt: !37)
+; CHECK: !37 = distinct !DILocation(line: 6, scope: !27)
@addr = common local_unnamed_addr global i8*** null, align 4, !dbg !0
Index: llvm/lib/CodeGen/SafeStack.cpp
===================================================================
--- llvm/lib/CodeGen/SafeStack.cpp
+++ llvm/lib/CodeGen/SafeStack.cpp
@@ -49,6 +49,7 @@
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
@@ -645,6 +646,13 @@
// FIXME: no need to update BasePointer in leaf functions.
unsigned FrameSize = alignTo(SSL.getFrameSize(), StackAlignment);
+ MDBuilder MDB(F.getContext());
+ SmallVector<Metadata *, 2> Data;
+ Data.push_back(MDB.createString("unsafe-stack-size"));
+ Data.push_back(MDB.createConstant(ConstantInt::get(Int32Ty, FrameSize)));
+ MDNode *MD = MDTuple::get(F.getContext(), Data);
+ F.setMetadata(LLVMContext::MD_annotation, MD);
+
// Update shadow stack pointer in the function epilogue.
IRB.SetInsertPoint(BasePointer->getNextNode());
Index: llvm/lib/CodeGen/PrologEpilogInserter.cpp
===================================================================
--- llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -285,6 +285,9 @@
assert(!Failed && "Invalid warn-stack-size fn attr value");
(void)Failed;
}
+ if (MF.getFunction().hasFnAttribute(Attribute::SafeStack)) {
+ StackSize += MFI.getUnsafeStackSize();
+ }
if (StackSize > Threshold) {
DiagnosticInfoStackSize DiagStackSize(F, StackSize, Threshold, DS_Warning);
F.getContext().diagnose(DiagStackSize);
Index: llvm/lib/CodeGen/MachineFunction.cpp
===================================================================
--- llvm/lib/CodeGen/MachineFunction.cpp
+++ llvm/lib/CodeGen/MachineFunction.cpp
@@ -109,6 +109,27 @@
llvm_unreachable("Invalid machine function property");
}
+void setUnsafeStackSize(const Function &F, MachineFrameInfo &FrameInfo) {
+ if (!F.hasFnAttribute(Attribute::SafeStack))
+ return;
+
+ auto *Existing =
+ dyn_cast_or_null<MDTuple>(F.getMetadata(LLVMContext::MD_annotation));
+
+ if (!Existing || Existing->getNumOperands() != 2)
+ return;
+
+ auto *MetadataName = "unsafe-stack-size";
+ if (auto &N = Existing->getOperand(0)) {
+ if (cast<MDString>(N.get())->getString() == MetadataName) {
+ if (auto &Op = Existing->getOperand(1)) {
+ auto Val = mdconst::extract<ConstantInt>(Op)->getZExtValue();
+ FrameInfo.setUnsafeStackSize(Val);
+ }
+ }
+ }
+}
+
// Pin the vtable to this file.
void MachineFunction::Delegate::anchor() {}
@@ -177,6 +198,8 @@
/*ForcedRealign=*/CanRealignSP &&
F.hasFnAttribute(Attribute::StackAlignment));
+ setUnsafeStackSize(F, *FrameInfo);
+
if (F.hasFnAttribute(Attribute::StackAlignment))
FrameInfo->ensureMaxAlignment(*F.getFnStackAlign());
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1208,7 +1208,8 @@
return;
const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
- uint64_t StackSize = FrameInfo.getStackSize();
+ uint64_t StackSize =
+ FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
if (StackUsageStream == nullptr) {
std::error_code EC;
Index: llvm/include/llvm/CodeGen/MachineFrameInfo.h
===================================================================
--- llvm/include/llvm/CodeGen/MachineFrameInfo.h
+++ llvm/include/llvm/CodeGen/MachineFrameInfo.h
@@ -335,6 +335,9 @@
/// Not null, if shrink-wrapping found a better place for the epilogue.
MachineBasicBlock *Restore = nullptr;
+ /// Size of the UnsafeStack Frame
+ uint64_t UnsafeStackSize = 0;
+
public:
explicit MachineFrameInfo(unsigned StackAlignment, bool StackRealignable,
bool ForcedRealign)
@@ -773,6 +776,9 @@
MachineBasicBlock *getRestorePoint() const { return Restore; }
void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; }
+ uint64_t getUnsafeStackSize() const { return UnsafeStackSize; }
+ void setUnsafeStackSize(uint64_t Size) { UnsafeStackSize = Size; }
+
/// Return a set of physical registers that are pristine.
///
/// Pristine registers hold a value that is useless to the current function,
Index: clang/test/Frontend/stack-usage-safestack.c
===================================================================
--- /dev/null
+++ clang/test/Frontend/stack-usage-safestack.c
@@ -0,0 +1,20 @@
+/// Check that stack frame size warnings behave the same when safe stack is enabled
+
+// RUN: %clang_cc1 %s -fwarn-stack-size=48 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=REGULAR %s
+// RUN: %clang_cc1 %s -fwarn-stack-size=1060 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=IGNORE %s
+
+// RUN: %clang_cc1 %s -fsanitize=safe-stack -fwarn-stack-size=48 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=SAFESTACK %s
+// RUN: %clang_cc1 %s -fsanitize=safe-stack -fwarn-stack-size=1060 -S -o - -triple=i386-apple-darwin 2>&1 | FileCheck --check-prefix=IGNORE %s
+
+extern void init(int *buf, int size);
+extern int use_buf(int *buf, int size);
+
+// REGULAR: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// SAFESTACK: warning: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+// IGNORE-NOT: stack frame size ([[#]]) exceeds limit ([[#]]) in 'stackSizeWarning'
+void stackSizeWarning() {
+ int buf[256];
+ init(buf, sizeof(buf));
+ if (buf[0] < 42)
+ use_buf(buf, sizeof(buf));
+}
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