Added -ffake-address-space-map option to generate LLVM IR address spaces

Previously, shamrock was not able to get address space attributes from
LLVM's getAddressSpace() API for function (kernel) arguments, as they
didn't exist in the generated LLVM IR.

Now, we use a clang option to force address space mapping, causing
addrspace(<n>) attrs to be inserted.

See the discussion here:
https://www.mail-archive.com/cfe-commits@cs.uiuc.edu/msg76370.html

This was a necessary step to get many of the Khronos basic tests involving
local variables and parameters to not crash.

Signed-off-by: Gil Pitney <gil.pitney@linaro.org>

4 files changed, 15 insertions, 9 deletions

diff --git a/src/builtins/CMakeLists.txt b/src/builtins/CMakeLists.txt
index a83dfdf..d91c775 100644
--- a/src/builtins/CMakeLists.txt
+++ b/src/builtins/CMakeLists.txt
@@ -1,6 +1,6 @@
 if (SHAMROCK_BUILD)
 
-set(CUSTOM_COMMAND ${CLANG_EXECUTABLE} -cc1 -emit-llvm-bc -x cl -O2 -fno-builtin -nobuiltininc  -Fvisibility=protected -cl-std=CL1.2 -ffp-contract=off )
+set(CUSTOM_COMMAND ${CLANG_EXECUTABLE} -cc1 -emit-llvm-bc -x cl -O2 -fno-builtin -nobuiltininc  -Fvisibility=protected -ffake-address-space-map -cl-std=CL1.2 -ffp-contract=off )
 
 FILE(GLOB CL_SOURCES ${CLC_BUILTINS_DIR}/*.cl)
 #MESSAGE(STATUS "CL_SOURCES: ${CL_SOURCES}" )
diff --git a/src/core/compiler.cpp b/src/core/compiler.cpp
index d4d5240..eb121cb 100644
--- a/src/core/compiler.cpp
+++ b/src/core/compiler.cpp
@@ -127,6 +127,10 @@ int Compiler::compile(const std::string &options,
     if (devtype == CL_DEVICE_TYPE_CPU) {
        // Originally: target_opts.Triple = llvm::sys::getHostTriple();
        target_opts.Triple = llvm::sys::getDefaultTargetTriple();
+       // For CPU, we need OpenCL address space modifiers on our data types.
+       // This setting achieves that, and shamrock needs to know clang's address mapping.
+       // In the future, if we ever get a SPIR->ARM backend, this may be unnecessary.
+       lang_opts.FakeAddressSpaceMap = true;
     }
     else // devtype != CL_DEVICE_TYPE_CPU
     {
@@ -286,7 +290,7 @@ int Compiler::compile(const std::string &options,
     p_module = Act->takeModule();
 
     // uncomment to debug the llvm IR
-    // p_module->dump();  
+    // p_module->dump();
 
     return false;
 }
diff --git a/src/core/kernel.cpp b/src/core/kernel.cpp
index 4c53576..76c7ab8 100644
--- a/src/core/kernel.cpp
+++ b/src/core/kernel.cpp
@@ -178,7 +178,8 @@ cl_int Kernel::addFunction(DeviceInterface *device, llvm::Function *function,
             // It's a pointer, dereference it
             llvm::PointerType *p_type = llvm::cast<llvm::PointerType>(arg_type);
 
-            file = (Arg::File)p_type->getAddressSpace();
+            unsigned int space = p_type->getAddressSpace();
+            file = (Arg::File)space;
             arg_type = p_type->getElementType();
 
             // If it's a __local argument, we'll have to allocate memory at run time
diff --git a/src/core/kernel.h b/src/core/kernel.h
index 80672ea..d633aa2 100644
--- a/src/core/kernel.h
+++ b/src/core/kernel.h
@@ -90,15 +90,16 @@ class Kernel : public Object
                 enum File
                 {
                     Private = 0,  /*!< \brief __private */
-#if 1
+#ifdef SHAMROCK_BUILD
+                    /* clang -ffake-address-space-map mappings, LLVM IR */
+                    Global = 1,   /*!< \brief __global */
+                    Local = 2,    /*!< \brief __local */
+                    Constant = 3     /*!< \brief __constant */
+#else
+                    /* Mapping used by TI DSP (SPIR) */
                     Global = 1,   /*!< \brief __global */
                     Constant = 2, /*!< \brief __constant */
                     Local = 3     /*!< \brief __local */
-#else
-                    /* using clang defaults */
-                    Global   = 0xFFFF00, /*!< \brief __global */
-                    Local    = 0xFFFF01, /*!< \brief __local */
-                    Constant = 0xFFFF02  /*!< \brief __constant */
 #endif
                 };