Merge pull request #323 from delcypher/support_objectsize_intrinsic

Implement support for lowering the ``llvm.objectsize`` intrinsic

4 files changed, 96 insertions, 1 deletions

diff --git a/lib/Module/IntrinsicCleaner.cpp b/lib/Module/IntrinsicCleaner.cpp
index da97621a..54ad7db7 100644
--- a/lib/Module/IntrinsicCleaner.cpp
+++ b/lib/Module/IntrinsicCleaner.cpp
@@ -232,7 +232,30 @@ bool IntrinsicCleanerPass::runOnBasicBlock(BasicBlock &b, Module &M) {
         dirty = true;
         break;
       }
-                    
+      case Intrinsic::objectsize: {
+        // We don't know the size of an object in general so we replace
+        // with 0 or -1 depending on the second argument to the intrinsic.
+        assert(ii->getNumArgOperands() == 2 && "wrong number of arguments");
+        Value *minArg = ii->getArgOperand(1);
+        assert(minArg && "Failed to get second argument");
+        ConstantInt *minArgAsInt = dyn_cast<ConstantInt>(minArg);
+        assert(minArgAsInt && "Second arg is not a ConstantInt");
+        assert(minArgAsInt->getBitWidth() == 1 && "Second argument is not an i1");
+        Value *replacement = NULL;
+        LLVM_TYPE_Q IntegerType *intType = dyn_cast<IntegerType>(ii->getType());
+        assert(intType && "intrinsic does not have integer return type");
+        if (minArgAsInt->isZero()) {
+          // min=false
+          replacement = ConstantInt::get(intType, -1, /*isSigned=*/true);
+        } else {
+          // min=true
+          replacement = ConstantInt::get(intType, 0, /*isSigned=*/false);
+        }
+        ii->replaceAllUsesWith(replacement);
+        ii->eraseFromParent();
+        dirty = true;
+        break;
+      }
       default:
         if (LowerIntrinsics)
           IL->LowerIntrinsicCall(ii);
diff --git a/test/Intrinsics/objectsize.ll b/test/Intrinsics/objectsize.ll
new file mode 100644
index 00000000..8b75ce8f
--- /dev/null
+++ b/test/Intrinsics/objectsize.ll
@@ -0,0 +1,36 @@
+; Unfortunately LLVM 2.9 has a different suffix for the ``llvm.objectsize`` instrinsic
+; so this LLVM IR fails to verify for that version.
+;
+; REQUIRES: not-llvm-2.9
+; RUN: %llvmas %s -o=%t.bc
+; RUN: rm -rf %t.klee-out
+; RUN: %klee -exit-on-error --output-dir=%t.klee-out -disable-opt %t.bc
+; ModuleID = 'objectsize.c'
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @main() nounwind uwtable {
+entry:
+  %a = alloca i8*, align 8
+  %0 = load i8** %a, align 8
+  %1 = call i64 @llvm.objectsize.i64.p0i8(i8* %0, i1 true)
+  %cmp = icmp ne i64 %1, 0
+  br i1 %cmp, label %abort.block, label %continue.block
+
+continue.block:
+  %2 = load i8** %a, align 8
+  %3 = call i64 @llvm.objectsize.i64.p0i8(i8* %2, i1 false)
+  %cmp1 = icmp ne i64 %3, -1
+  br i1 %cmp1, label %abort.block, label %exit.block
+
+exit.block:
+  ret i32 0
+
+abort.block:
+  call void @abort()
+  unreachable
+}
+
+declare i64 @llvm.objectsize.i64.p0i8(i8*, i1) nounwind readnone
+
+declare void @abort() noreturn nounwind
diff --git a/test/Intrinsics/objectsize.llvm29.ll b/test/Intrinsics/objectsize.llvm29.ll
new file mode 100644
index 00000000..386eaddb
--- /dev/null
+++ b/test/Intrinsics/objectsize.llvm29.ll
@@ -0,0 +1,34 @@
+; FIXME: Remove this test case when we drop LLVM 2.9 support
+; REQUIRES: llvm-2.9
+; RUN: %llvmas %s -o=%t.bc
+; RUN: rm -rf %t.klee-out
+; RUN: %klee -exit-on-error --output-dir=%t.klee-out -disable-opt %t.bc
+; ModuleID = 'objectsize.c'
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @main() nounwind {
+entry:
+  %a = alloca i8*, align 8
+  %0 = load i8** %a, align 8
+  %1 = call i64 @llvm.objectsize.i64(i8* %0, i1 true)
+  %cmp = icmp ne i64 %1, 0
+  br i1 %cmp, label %abort.block, label %continue.block
+
+continue.block:
+  %2 = load i8** %a, align 8
+  %3 = call i64 @llvm.objectsize.i64(i8* %2, i1 false)
+  %cmp1 = icmp ne i64 %3, -1
+  br i1 %cmp1, label %abort.block, label %exit.block
+
+exit.block:
+  ret i32 0
+
+abort.block:
+  call void @abort()
+  unreachable
+}
+
+declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readnone
+
+declare void @abort() noreturn nounwind
diff --git a/test/lit.cfg b/test/lit.cfg
index 06ad17aa..f1253ea6 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -85,6 +85,8 @@ for name in subs:
 
 # Add a substitution for lli.
 config.substitutions.append( ('%lli', os.path.join(llvm_tools_dir, 'lli')) )
+# Add a substitution for llvm-as
+config.substitutions.append( ('%llvmas', os.path.join(llvm_tools_dir, 'llvm-as')) )
 
 # Get KLEE and Kleaver specific parameters passed on llvm-lit cmd line
 # e.g. llvm-lit --param klee_opts=--help