When substituting sunkaddrs into indirect arguments an asm, we were

walking the asm arguments once and stashing their Values.  This is
wrong because the same memory location can be in the list twice, and
if the first one has a sunkaddr substituted, the stashed value for the
second one will be wrong (use-after-free).  PR 8154.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114104 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 60 insertions, 2 deletions

diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 02282820fc..437de38131 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -738,6 +738,7 @@ bool CodeGenPrepare::OptimizeInlineAsmInst(Instruction *I, CallSite CS,
   bool MadeChange = false;
 
   std::vector<TargetLowering::AsmOperandInfo> TargetConstraints = TLI->ParseConstraints(CS);
+  unsigned ArgNo = 0;
   for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
     TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
     
@@ -746,9 +747,10 @@ bool CodeGenPrepare::OptimizeInlineAsmInst(Instruction *I, CallSite CS,
 
     if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
         OpInfo.isIndirect) {
-      Value *OpVal = OpInfo.CallOperandVal;
+      Value *OpVal = const_cast<Value *>(CS.getArgument(ArgNo++));
       MadeChange |= OptimizeMemoryInst(I, OpVal, OpVal->getType(), SunkAddrs);
-    }
+    } else if (OpInfo.Type == InlineAsm::isInput)
+      ArgNo++;
   }
 
   return MadeChange;
diff --git a/test/CodeGen/X86/2010-09-16-asmcrash.ll b/test/CodeGen/X86/2010-09-16-asmcrash.ll
new file mode 100644
index 0000000000..9bbd691942
--- /dev/null
+++ b/test/CodeGen/X86/2010-09-16-asmcrash.ll
@@ -0,0 +1,56 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-freebsd8.1 -o /dev/null
+; This formerly crashed, PR 8154.
+
+module asm ".weak sem_close"
+module asm ".equ sem_close, _sem_close"
+module asm ".weak sem_destroy"
+module asm ".equ sem_destroy, _sem_destroy"
+module asm ".weak sem_getvalue"
+module asm ".equ sem_getvalue, _sem_getvalue"
+module asm ".weak sem_init"
+module asm ".equ sem_init, _sem_init"
+module asm ".weak sem_open"
+module asm ".equ sem_open, _sem_open"
+module asm ".weak sem_post"
+module asm ".equ sem_post, _sem_post"
+module asm ".weak sem_timedwait"
+module asm ".equ sem_timedwait, _sem_timedwait"
+module asm ".weak sem_trywait"
+module asm ".equ sem_trywait, _sem_trywait"
+module asm ".weak sem_unlink"
+module asm ".equ sem_unlink, _sem_unlink"
+module asm ".weak sem_wait"
+module asm ".equ sem_wait, _sem_wait"
+
+%struct._sem = type { i32, %struct._usem }
+%struct._usem = type { i32, i32, i32 }
+
+define void @_sem_timedwait(%struct._sem* noalias %sem) nounwind ssp {
+entry:
+  br i1 undef, label %while.cond.preheader, label %sem_check_validity.exit
+
+while.cond.preheader:                             ; preds = %entry
+  %tmp4 = getelementptr inbounds %struct._sem* %sem, i64 0, i32 1, i32 1
+  br label %while.cond
+
+sem_check_validity.exit:                          ; preds = %entry
+  ret void
+
+while.cond:                                       ; preds = %while.body, %while.cond.preheader
+  br i1 undef, label %while.body, label %while.end
+
+while.body:                                       ; preds = %while.cond
+  %0 = call i8 asm sideeffect "\09lock ; \09\09\09cmpxchgl $2,$1 ;\09       sete\09$0 ;\09\091:\09\09\09\09# atomic_cmpset_int", "={ax},=*m,r,{ax},*m,~{memory},~{dirflag},~{fpsr},~{flags}"(i32* %tmp4, i32 undef, i32 undef, i32* %tmp4) nounwind, !srcloc !0
+  br i1 undef, label %while.cond, label %return
+
+while.end:                                        ; preds = %while.cond
+  br i1 undef, label %if.end18, label %return
+
+if.end18:                                         ; preds = %while.end
+  unreachable
+
+return:                                           ; preds = %while.end, %while.body
+  ret void
+}
+
+!0 = metadata !{i32 158484}