[OpenMP] Fix redefining stdint.h types (llvm#108607)

Summary:
We can include `stdint.h` just fine as long as we don't allow it to find
system headers, passing `-nostdlibinc` and `-nogpuinc` suppresses these
extra paths so we will just use the clang resource headers for
`stdint.h` and `stddef.h`.

offload/DeviceRTL/CMakeLists.txt

@@ -125,7 +125,7 @@ list(TRANSFORM LIBOMPTARGET_LLVM_INCLUDE_DIRS_DEVICERTL PREPEND "-I")
 # Set flags for LLVM Bitcode compilation.
 set(bc_flags -c -foffload-lto -std=c++17 -fvisibility=hidden
               ${clang_opt_flags} --offload-device-only
-             -nocudalib -nogpulib -nostdinc
+             -nocudalib -nogpulib -nogpuinc -nostdlibinc
              -fopenmp -fopenmp-cuda-mode
              -Wno-unknown-cuda-version
              -DOMPTARGET_DEVICE_RUNTIME
@@ -270,7 +270,7 @@ function(compileDeviceRTLLibrary target_cpu target_name target_triple)
       -fopenmp --offload-arch=${target_cpu} -fopenmp-cuda-mode
       -mllvm -openmp-opt-disable
       -foffload-lto -fvisibility=hidden --offload-device-only
-      -nocudalib -nogpulib -nostdinc -Wno-unknown-cuda-version
+      -nocudalib -nogpulib -nogpuinc -nostdlibinc -Wno-unknown-cuda-version
     )
     target_compile_definitions(${ide_target_name} PRIVATE SHARED_SCRATCHPAD_SIZE=512)
     target_include_directories(${ide_target_name} PRIVATE

offload/DeviceRTL/include/DeviceTypes.h

@@ -12,6 +12,9 @@
 #ifndef OMPTARGET_TYPES_H
 #define OMPTARGET_TYPES_H
 
+#include <stddef.h>
+#include <stdint.h>
+
 // Tell the compiler that we do not have any "call-like" inline assembly in the
 // device rutime. That means we cannot have inline assembly which will call
 // another function but only inline assembly that performs some operation or
@@ -21,32 +24,6 @@
 // TODO: Find a good place for this
 #pragma omp assumes ext_no_call_asm
 
-/// Base type declarations for freestanding mode
-///
-///{
-using int8_t = char;
-using uint8_t = unsigned char;
-using int16_t = short;
-using uint16_t = unsigned short;
-using int32_t = int;
-using uint32_t = unsigned int;
-using int64_t = long;
-using uint64_t = unsigned long;
-using size_t = decltype(sizeof(char));
-// TODO: Properly implement this
-using intptr_t = int64_t;
-using uintptr_t = uint64_t;
-
-static_assert(sizeof(int8_t) == 1, "type size mismatch");
-static_assert(sizeof(uint8_t) == 1, "type size mismatch");
-static_assert(sizeof(int16_t) == 2, "type size mismatch");
-static_assert(sizeof(uint16_t) == 2, "type size mismatch");
-static_assert(sizeof(int32_t) == 4, "type size mismatch");
-static_assert(sizeof(uint32_t) == 4, "type size mismatch");
-static_assert(sizeof(int64_t) == 8, "type size mismatch");
-static_assert(sizeof(uint64_t) == 8, "type size mismatch");
-///}
-
 enum omp_proc_bind_t {
   omp_proc_bind_false = 0,
   omp_proc_bind_true = 1,

offload/include/Shared/Environment.h

@@ -13,13 +13,13 @@
 #ifndef OMPTARGET_SHARED_ENVIRONMENT_H
 #define OMPTARGET_SHARED_ENVIRONMENT_H
 
+#include <stdint.h>
+
 #ifdef OMPTARGET_DEVICE_RUNTIME
-#include "Types.h"
+#include "DeviceTypes.h"
 #else
 #include "SourceInfo.h"
 
-#include <cstdint>
-
 using IdentTy = ident_t;
 #endif
 

offload/include/Shared/Utils.h

@@ -14,7 +14,7 @@
 #ifndef OMPTARGET_SHARED_UTILS_H
 #define OMPTARGET_SHARED_UTILS_H
 
-#include "Types.h"
+#include <stdint.h>
 
 namespace utils {