[llvm] 31be9f3 - Fix clone_constant_impl to correctly deal with null pointers

[via llvm-commits]

Author: aqjune
Date: 2019-11-05T13:53:52+09:00
New Revision: 31be9f3f7dee80c586d3beac9a65663d5628cf96

URL: https://github.com/llvm/llvm-project/commit/31be9f3f7dee80c586d3beac9a65663d5628cf96
DIFF: https://github.com/llvm/llvm-project/commit/31be9f3f7dee80c586d3beac9a65663d5628cf96.diff

LOG: Fix clone_constant_impl to correctly deal with null pointers

Summary:
This patch resolves llvm-c-test's following error

```
LLVM ERROR: LLVMGetValueKind returned incorrect type
```

which arises when the input bitcode contains a null pointer.

Reviewers: jdoerfert, CodaFi, deadalnix

Reviewed By: jdoerfert

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68928

Added: 
    

Modified: 
    llvm/test/Bindings/llvm-c/echo.ll
    llvm/tools/llvm-c-test/echo.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/test/Bindings/llvm-c/echo.ll b/llvm/test/Bindings/llvm-c/echo.ll
index c29991a12213..a244a65d91f9 100644
--- a/llvm/test/Bindings/llvm-c/echo.ll
+++ b/llvm/test/Bindings/llvm-c/echo.ll
@@ -21,6 +21,7 @@ module asm "classical GAS"
 @protected = protected global i32 23
 @section = global i32 27, section ".custom"
 @align = global i32 31, align 4
+ at nullptr = global i32* null
 
 @aliased1 = alias i32, i32* @var
 @aliased2 = internal alias i32, i32* @var

diff  --git a/llvm/tools/llvm-c-test/echo.cpp b/llvm/tools/llvm-c-test/echo.cpp
index 4d10a4bbfc05..8abbfb3fb0c0 100644
--- a/llvm/tools/llvm-c-test/echo.cpp
+++ b/llvm/tools/llvm-c-test/echo.cpp
@@ -326,6 +326,13 @@ static LLVMValueRef clone_constant_impl(LLVMValueRef Cst, LLVMModuleRef M) {
                                     EltCount, LLVMIsPackedStruct(Ty));
   }
 
+  // Try ConstantPointerNull
+  if (LLVMIsAConstantPointerNull(Cst)) {
+    check_value_kind(Cst, LLVMConstantPointerNullValueKind);
+    LLVMTypeRef Ty = TypeCloner(M).Clone(Cst);
+    return LLVMConstNull(Ty);
+  }
+
   // Try undef
   if (LLVMIsUndef(Cst)) {
     check_value_kind(Cst, LLVMUndefValueValueKind);