Fix linux 32 bit unknown function error handling

The issue was that passing a string to loader_log wouldn't work, likely due
to relocation issues. Workaround is to create a bespoke function that contained
the format string embedded in it.

Additionally, CMAKE_SYSTEM_PROCESSOR is incorrect in the case of x86 builds on
x64. Checking for sizeof(void*) == 8 allows distinguishing building for 32 bit
and 64 bit, and so the correct gen_defines.asm is created while cross compiling.

Also rename the error to note that its a function which isn't supported, not
an extension.

9 files changed, 31 insertions, 11 deletions

diff --git a/loader/CMakeLists.txt b/loader/CMakeLists.txt
index eebb83a33..62f8e2c40 100644
--- a/loader/CMakeLists.txt
+++ b/loader/CMakeLists.txt
@@ -222,6 +222,15 @@ else() # i.e.: Linux
         endif()
     endif()
 
+    # When compiling for x86 on x64, we can't use CMAKE_SYSTEM_PROCESSOR to determine which architecture to use,
+    # Instead, check the size of void* and if its 4, set ASM_OFFSET_SYSTEM_PROCESSOR to x86
+    # Note - there is no 32 bit arm assembly code, so this only applies to x86 currently.
+    if("${CMAKE_SIZEOF_VOID_P}" EQUAL "8")
+        set(ASM_OFFSET_SYSTEM_PROCESSOR ${CMAKE_SYSTEM_PROCESSOR}) # x86_64 or aarch64
+    else()
+        set(ASM_OFFSET_SYSTEM_PROCESSOR "x86")
+    endif()
+
     if(ASSEMBLER_WORKS)
         add_executable(asm_offset asm_offset.c)
         target_link_libraries(asm_offset loader_specific_options)
@@ -243,14 +252,14 @@ else() # i.e.: Linux
             # Run parse_asm_values.py on asm_offset's assembly file to generate the gen_defines.asm, which the asm code depends on
             add_custom_command(TARGET asm_offset POST_BUILD
                 COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_SOURCE_DIR}/scripts/parse_asm_values.py "$<TARGET_FILE_DIR:asm_offset>/gen_defines.asm"
-                    "${ASM_OFFSET_INTERMEDIATE_LOCATION}" "GAS" "${CMAKE_CXX_COMPILER_ID}" "${CMAKE_SYSTEM_PROCESSOR}"
+                    "${ASM_OFFSET_INTERMEDIATE_LOCATION}" "GAS" "${CMAKE_CXX_COMPILER_ID}" "${ASM_OFFSET_SYSTEM_PROCESSOR}"
                 BYPRODUCTS gen_defines.asm
                 )
         endif()
         add_custom_target(loader_asm_gen_files DEPENDS gen_defines.asm)
     else()
         if(USE_GAS)
-            message(WARNING "Could not find working ${CMAKE_SYSTEM_PROCESSOR} GAS assembler\n${ASM_FAILURE_MSG}")
+            message(WARNING "Could not find working ${ASM_OFFSET_SYSTEM_PROCESSOR} GAS assembler\n${ASM_FAILURE_MSG}")
         else()
             message(WARNING "Assembly sources have been disabled\n${ASM_FAILURE_MSG}")
         endif()
diff --git a/loader/log.c b/loader/log.c
index 6b68bd0dc..ab64f6336 100644
--- a/loader/log.c
+++ b/loader/log.c
@@ -229,3 +229,8 @@ void loader_log(const struct loader_instance *inst, VkFlags msg_type, int32_t ms
         assert(false);
     }
 }
+
+void loader_log_asm_function_not_supported(const struct loader_instance *inst, VkFlags msg_type, int32_t msg_code,
+                                           const char *func_name) {
+    loader_log(inst, msg_type, msg_code, "Function %s not supported for this physical device", func_name);
+}
diff --git a/loader/log.h b/loader/log.h
index 84bf6e199..b45a26494 100644
--- a/loader/log.h
+++ b/loader/log.h
@@ -49,3 +49,8 @@ uint32_t loader_get_debug_level(void);
 // Logs a message to stderr
 // May output to DebugUtils if the instance isn't null and the extension is enabled.
 void loader_log(const struct loader_instance *inst, VkFlags msg_type, int32_t msg_code, const char *format, ...);
+
+// Used for the assembly code to emit an specific error message
+// This is a work around for linux 32 bit error handling not passing relocatable strings correctly
+void loader_log_asm_function_not_supported(const struct loader_instance *inst, VkFlags msg_type, int32_t msg_code,
+                                           const char *func_name);
diff --git a/loader/unknown_ext_chain.c b/loader/unknown_ext_chain.c
index 3ce7f3b1c..93d71bfb2 100644
--- a/loader/unknown_ext_chain.c
+++ b/loader/unknown_ext_chain.c
@@ -48,7 +48,7 @@
         struct loader_icd_term *icd_term = phys_dev_term->this_icd_term;                                           \
         struct loader_instance *inst = (struct loader_instance *)icd_term->this_instance;                          \
         if (NULL == icd_term->phys_dev_ext[num]) {                                                                 \
-            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "Extension %s not supported for this physical device",    \
+            loader_log(inst, VULKAN_LOADER_ERROR_BIT, 0, "Function %s not supported for this physical device",    \
                        inst->phys_dev_ext_disp_functions[num]);                                                    \
         }                                                                                                          \
         icd_term->phys_dev_ext[num](phys_dev_term->phys_dev);                                                      \
diff --git a/loader/unknown_ext_chain_gas_aarch64.S b/loader/unknown_ext_chain_gas_aarch64.S
index 5a7d98a07..b2c65ee77 100644
--- a/loader/unknown_ext_chain_gas_aarch64.S
+++ b/loader/unknown_ext_chain_gas_aarch64.S
@@ -76,7 +76,7 @@ vkdev_ext\num:
 .data
 
 termin_error_string:
-.string "Extension %s not supported for this physical device"
+.string "Function %s not supported for this physical device"
 
 .text
 
diff --git a/loader/unknown_ext_chain_gas_x86.S b/loader/unknown_ext_chain_gas_x86.S
index 496208ddf..759375c23 100644
--- a/loader/unknown_ext_chain_gas_x86.S
+++ b/loader/unknown_ext_chain_gas_x86.S
@@ -100,12 +100,11 @@ vkPhysDevExtTermin\num:
     jmp     [eax + (DISPATCH_OFFSET_ICD_TERM + (PTR_SIZE * \num))]              # Jump to the next function in the chain
 terminError\num:
     mov     eax, dword ptr [eax + INSTANCE_OFFSET_ICD_TERM]                       # Load the loader_instance into eax
-    push    dword ptr [eax + (FUNCTION_OFFSET_INSTANCE + (CHAR_PTR_SIZE * \num))] # Push the func name (fifth arg)
-    push    offset termin_error_string@GOT                                        # Push the error string (fourth arg)
+    push    dword ptr [eax + (FUNCTION_OFFSET_INSTANCE + (CHAR_PTR_SIZE * \num))] # Push the func name (fourth arg)
     push    0                                                                     # Push zero (third arg)
     push    VULKAN_LOADER_ERROR_BIT                                               # Push the error logging bit (second arg)
     push    eax                                                                   # Push the loader_instance (first arg)
-    call    loader_log                                                            # Log the error message before we crash
+    call    loader_log_asm_function_not_supported                                 # Log the error message before we crash
     add     esp, 20                                                               # Clean up the args
     mov     eax, 0
     jmp     eax                                                         # Crash intentionally by jumping to address zero
@@ -129,7 +128,7 @@ vkdev_ext\num:
 .data
 
 termin_error_string:
-.string "Extension %s not supported for this physical device"
+.string "Function %s not supported for this physical device"
 
 .text
 
diff --git a/loader/unknown_ext_chain_masm.asm b/loader/unknown_ext_chain_masm.asm
index e33858aeb..46d13de47 100644
--- a/loader/unknown_ext_chain_masm.asm
+++ b/loader/unknown_ext_chain_masm.asm
@@ -119,7 +119,7 @@ endm
 ENDIF
 
 .const
-    termin_error_string db 'Extension %s not supported for this physical device', 0
+    termin_error_string db 'Function %s not supported for this physical device', 0
 
 .code
 
diff --git a/scripts/parse_asm_values.py b/scripts/parse_asm_values.py
index bff263d2a..df7a0460c 100644
--- a/scripts/parse_asm_values.py
+++ b/scripts/parse_asm_values.py
@@ -35,7 +35,8 @@ source_asm_file = sys.argv[2]
 assembler_type = sys.argv[3]
 # Whether we are using gcc, clang, or msvc
 compiler = sys.argv[4]
-# taken from CMAKE_SYSTEM_PROCESSOR - x86_64 or aarch64
+# taken from CMAKE_SYSTEM_PROCESSOR - x86_64, aarch64, or x86
+# Only used with GAS - MASM doesn't need this, as it has its own way to determine x86 vs x64
 arch = sys.argv[5]
 
 if destination_file is None or source_asm_file is None or assembler_type is None or compiler is None or arch is None:
@@ -71,6 +72,7 @@ with open(destination_file, "w", encoding="utf-8") as dest:
             dest.write(".set X86_64, 1\n")
         elif arch == "aarch64":
             dest.write(".set AARCH_64, 1\n")
+        # Nothing to write in the x86 case
 
     for d in defines:
         match = None
diff --git a/tests/loader_unknown_ext_tests.cpp b/tests/loader_unknown_ext_tests.cpp
index 294251afe..bdce9b68c 100644
--- a/tests/loader_unknown_ext_tests.cpp
+++ b/tests/loader_unknown_ext_tests.cpp
@@ -445,7 +445,7 @@ TEST(UnknownFunctionDeathTests, PhysicalDeviceFunctionErrorPath) {
     decltype(custom_physical_device_functions::func_zero)* returned_func_i =
         env.vulkan_functions.load(inst.inst, function_names.at(0).c_str());
     ASSERT_NE(returned_func_i, nullptr);
-    ASSERT_DEATH(returned_func_i(phys_dev_to_use, 0), "Extension vkNotIntRealFuncTEST_0 not supported for this physical device");
+    ASSERT_DEATH(returned_func_i(phys_dev_to_use, 0), "Function vkNotIntRealFuncTEST_0 not supported for this physical device");
 }
 
 TEST(UnknownFunction, PhysicalDeviceFunctionWithImplicitLayerImplementation) {