Align the data section correctly when loading an ELF file.

Patch by Amara Emerson.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166920 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/ExecutionEngine/MCJIT/test-data-align.ll b/test/ExecutionEngine/MCJIT/test-data-align.ll
new file mode 100644 (file)
index 0000000..0493cba
--- /dev/null
+++ b/test/ExecutionEngine/MCJIT/test-data-align.ll
@@ -0,0 +1,15 @@
+; RUN:  %lli -mtriple=%mcjit_triple -use-mcjit -O0 %s
+
+; Check that a variable is always aligned as specified.
+
+@var = global i32 0, align 32
+define i32 @main() {
+  %addr = ptrtoint i32* @var to i64
+  %mask = and i64 %addr, 31
+  %tst = icmp eq i64 %mask, 0
+  br i1 %tst, label %good, label %bad
+good:
+  ret i32 0
+bad:
+  ret i32 1
+}

diff --git a/tools/lli/lli.cpp b/tools/lli/lli.cpp
index 0ee72387b8111f3de4698a2d64f45af72c99baca..532980a8605afb980866955db354109100fda085 100644 (file)
--- a/tools/lli/lli.cpp
+++ b/tools/lli/lli.cpp
@@ -42,6 +42,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/Memory.h"
+#include "llvm/Support/MathExtras.h"
 #include <cerrno>
 
 #ifdef __linux__
@@ -303,9 +304,16 @@ uint8_t *LLIMCJITMemoryManager::allocateDataSection(uintptr_t Size,
                                                     unsigned SectionID) {
   if (!Alignment)
     Alignment = 16;
-  uint8_t *Addr = (uint8_t*)calloc((Size + Alignment - 1)/Alignment, Alignment);
-  AllocatedDataMem.push_back(sys::MemoryBlock(Addr, Size));
-  return Addr;
+  // Ensure that enough memory is requested to allow aligning.
+  size_t NumElementsAligned = 1 + (Size + Alignment - 1)/Alignment;
+  uint8_t *Addr = (uint8_t*)calloc(NumElementsAligned, Alignment);
+
+  // Honour the alignment requirement.
+  uint8_t *AlignedAddr = (uint8_t*)RoundUpToAlignment((uint64_t)Addr, Alignment);
+
+  // Store the original address from calloc so we can free it later.
+  AllocatedDataMem.push_back(sys::MemoryBlock(Addr, NumElementsAligned*Alignment));
+  return AlignedAddr;
 }
 
 uint8_t *LLIMCJITMemoryManager::allocateCodeSection(uintptr_t Size,