MemoryBuiltins: add support to determine the size of strdup'ed non-constant strings

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160742 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 7 deletions

diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index 4833b5212b..21417781bd 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/BuildLibCalls.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
@@ -448,11 +449,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
   return std::make_pair(Size, Zero);
 
   // TODO: handle more standard functions (+ wchar cousins):
-  // - strdup / strndup
   // - strcpy / strncpy
   // - strcat / strncat
   // - memcpy / memmove
-  // - strcat / strncat
   // - memset
 }
 
@@ -524,8 +523,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
 
 
 ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const TargetData *TD,
+                                                     const TargetLibraryInfo *TLI,
                                                      LLVMContext &Context)
-: TD(TD), Context(Context), Builder(Context, TargetFolder(TD)),
+: TD(TD), TLI(TLI), Context(Context), Builder(Context, TargetFolder(TD)),
 Visitor(TD, Context) {
   IntTy = TD->getIntPtrType(Context);
   Zero = ConstantInt::get(IntTy, 0);
@@ -619,8 +619,21 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
 
   // handle strdup-like functions separately
   if (FnData->AllocTy == StrDupLike) {
-    // TODO
-    return unknown();
+    IRBuilder<> StdBuilder(Builder.GetInsertPoint());
+    Value *Size;
+
+    // strdup(str): size =  strlen(str)+1
+    if (FnData->FstParam < 0)
+      Size = EmitStrLen(CS.getArgument(0), StdBuilder, TD, TLI);
+    else
+      // strndup(str, maxlen): size = strnlen(str, maxlen)+1
+      Size = EmitStrNLen(CS.getArgument(0), CS.getArgument(FnData->FstParam),
+                         StdBuilder, TD, TLI);
+    if (!Size)
+      return unknown();
+    Builder.SetInsertPoint(StdBuilder.GetInsertPoint());
+    Size = Builder.CreateNUWAdd(Size, ConstantInt::get(IntTy, 1));
+    return std::make_pair(Size, Zero);
   }
 
   Value *FirstArg = CS.getArgument(FnData->FstParam);
@@ -634,11 +647,9 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
   return std::make_pair(Size, Zero);
 
   // TODO: handle more standard functions (+ wchar cousins):
-  // - strdup / strndup
   // - strcpy / strncpy
   // - strcat / strncat
   // - memcpy / memmove
-  // - strcat / strncat
   // - memset
 }