Index: bolt/CMakeLists.txt
===================================================================
--- bolt/CMakeLists.txt
+++ bolt/CMakeLists.txt
@@ -44,6 +44,8 @@
   endif()
 endif()
 
+option(BOLT_RT_MAX_MEM "Maximum memory for runtime allocations." 0xa00000)
+
 if (BOLT_ENABLE_RUNTIME)
   message(STATUS "Building BOLT runtime libraries for X86")
   ExternalProject_Add(bolt_rt
@@ -55,7 +57,8 @@
                -DCMAKE_BUILD_TYPE=Release
                -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
                -DCMAKE_INSTALL_PREFIX=${LLVM_BINARY_DIR}
-    BUILD_ALWAYS True
+               -DBOLT_RT_MAX_MEM=${BOLT_RT_MAX_MEM}
+          BUILD_ALWAYS True
     )
   install(CODE "execute_process\(COMMAND \${CMAKE_COMMAND} -DCMAKE_INSTALL_PREFIX=\${CMAKE_INSTALL_PREFIX} -P ${CMAKE_CURRENT_BINARY_DIR}/bolt_rt-bins/cmake_install.cmake \)"
     COMPONENT bolt)
Index: bolt/runtime/CMakeLists.txt
===================================================================
--- bolt/runtime/CMakeLists.txt
+++ bolt/runtime/CMakeLists.txt
@@ -14,6 +14,9 @@
   instr.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/config.h
   )
+option(BOLT_RT_MAX_MEM "Maximum memory for runtime allocations.")
+target_compile_definitions(bolt_rt_instr PRIVATE RUNTIME_MAX_MEMORY=${BOLT_RT_MAX_MEM})
+
 add_library(bolt_rt_hugify STATIC
   hugify.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/config.h
Index: bolt/runtime/instr.cpp
===================================================================
--- bolt/runtime/instr.cpp
+++ bolt/runtime/instr.cpp
@@ -206,7 +206,7 @@
 
 private:
   static constexpr uint64_t Magic = 0x1122334455667788ull;
-  uint64_t MaxSize = 0xa00000;
+  uint64_t MaxSize = RUNTIME_MAX_MEMORY;
   uint8_t *StackBase{nullptr};
   uint64_t StackSize{0};
   bool Shared{false};