[llvm] 2878ecc - [StackProtector] Fix crash with vararg due to not checking LocationSize validity.

[Amara Emerson via llvm-commits]

Author: Amara Emerson
Date: 2020-09-03T00:08:48-07:00
New Revision: 2878ecc90f1f22cf0b96c04a4124122db008a2a9

URL: https://github.com/llvm/llvm-project/commit/2878ecc90f1f22cf0b96c04a4124122db008a2a9
DIFF: https://github.com/llvm/llvm-project/commit/2878ecc90f1f22cf0b96c04a4124122db008a2a9.diff

LOG: [StackProtector] Fix crash with vararg due to not checking LocationSize validity.

Differential Revision: https://reviews.llvm.org/D87074

Added: 
    llvm/test/CodeGen/X86/stack-guard-memloc-vararg.ll

Modified: 
    llvm/lib/CodeGen/StackProtector.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/StackProtector.cpp b/llvm/lib/CodeGen/StackProtector.cpp
index e246c2e5f55c..3d961af8ec3e 100644
--- a/llvm/lib/CodeGen/StackProtector.cpp
+++ b/llvm/lib/CodeGen/StackProtector.cpp
@@ -170,7 +170,8 @@ bool StackProtector::HasAddressTaken(const Instruction *AI,
     // If this instruction accesses memory make sure it doesn't access beyond
     // the bounds of the allocated object.
     Optional<MemoryLocation> MemLoc = MemoryLocation::getOrNone(I);
-    if (MemLoc.hasValue() && MemLoc->Size.getValue() > AllocSize)
+    if (MemLoc.hasValue() && MemLoc->Size.hasValue() &&
+        MemLoc->Size.getValue() > AllocSize)
       return true;
     switch (I->getOpcode()) {
     case Instruction::Store:

diff  --git a/llvm/test/CodeGen/X86/stack-guard-memloc-vararg.ll b/llvm/test/CodeGen/X86/stack-guard-memloc-vararg.ll
new file mode 100644
index 000000000000..d881b6cfae3b
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stack-guard-memloc-vararg.ll
@@ -0,0 +1,17 @@
+; RUN: llc -mtriple=x86_64 -O0 < %s | FileCheck %s
+
+; Check that we don't crash on this input.
+; CHECK-LABEL: @foo
+; CHECK: __stack_chk_guard
+; CHECK: retq
+define hidden void @foo(i8** %ptr) #0 {
+entry:
+  %args.addr = alloca i8*, align 8
+  %0 = va_arg i8** %args.addr, i8*
+  store i8* %0, i8** %ptr
+  ret void
+}
+
+attributes #0 = { sspstrong }
+attributes #1 = { optsize }
+