xen: Support LLVM raw profile versions 5, 6, 7, 8, 9, and 10

This change enables compatibility for measuring code coverage
with Clang versions 11 through 20 by supporting their respective raw
profile formats.

1- Added support for LLVM raw profile versions 5, 6, 7, 8, 9, and 10.
2- Initialized llvm_profile_header for all versions based on llvm source
   code in compiler-rt/include/profile/InstrProfData.inc for each version.
3- We tested this patch for all Clang versions from 11 through 20
   on x86 platform.
4- Fixed linking warnings related to LLVM profile sections in x86.

Signed-off-by: Saman Dehghan <samaan.dehghan@gmail.com>
Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Tested-by: Wentao Zhang <wentaoz5@illinois.edu>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/arch/x86/xen.lds.S

@@ -186,6 +186,8 @@ SECTIONS
   } PHDR(note) PHDR(text)
 #endif
 
+  LLVM_COV_RO_DATA
+
   _erodata = .;
 
   . = ALIGN(SECTION_ALIGN);
@@ -323,6 +325,8 @@ SECTIONS
        *(.data .data.*)
   } PHDR(text)
 
+  LLVM_COV_RW_DATA
+
   DECL_SECTION(.bss) {
        __bss_start = .;
        *(.bss.page_aligned*)
@@ -357,6 +361,8 @@ SECTIONS
 
   DWARF2_DEBUG_SECTIONS
 
+  LLVM_COV_DEBUG
+
 #ifdef CONFIG_HYPERV_GUEST
   hv_hcall_page = ABSOLUTE(HV_HCALL_PAGE - XEN_VIRT_START + __XEN_VIRT_START);
 #endif

xen/common/coverage/llvm.c

@@ -44,27 +44,65 @@
     ((uint64_t)'f' << 16) | ((uint64_t)'R' << 8)  | ((uint64_t)129)
 #endif
 
-#define LLVM_PROFILE_VERSION    4
+#if __clang_major__ >= 19 && __clang_major__ <= 20
+#define LLVM_PROFILE_VERSION    10
+#define LLVM_PROFILE_NUM_KINDS  3
+#elif __clang_major__ == 18
+#define LLVM_PROFILE_VERSION    9
 #define LLVM_PROFILE_NUM_KINDS  2
+#elif __clang_major__ >= 14
+#define LLVM_PROFILE_VERSION    8
+#define LLVM_PROFILE_NUM_KINDS  2
+#elif __clang_major__ == 13
+#define LLVM_PROFILE_VERSION    7
+#define LLVM_PROFILE_NUM_KINDS  2
+#elif __clang_major__ >= 11
+#define LLVM_PROFILE_VERSION    5
+#define LLVM_PROFILE_NUM_KINDS  2
+#else
+#error "LLVM coverage selected but an unsupported clang version is used"
+#endif
 
 struct llvm_profile_data {
     uint64_t name_ref;
     uint64_t function_hash;
-    void *counter;
+    void *relative_counter;
+#if LLVM_PROFILE_VERSION >= 9
+    void *relative_bitmap;
+#endif
     void *function;
     void *values;
     uint32_t nr_counters;
     uint16_t nr_value_sites[LLVM_PROFILE_NUM_KINDS];
+#if LLVM_PROFILE_VERSION >= 9
+    uint32_t numbitmap_bytes;
+#endif
 };
 
 struct llvm_profile_header {
     uint64_t magic;
     uint64_t version;
-    uint64_t data_size;
-    uint64_t counters_size;
+#if LLVM_PROFILE_VERSION >= 7
+    uint64_t binary_ids_size;
+#endif
+    uint64_t num_data;
+    uint64_t padding_bytes_before_counters;
+    uint64_t num_counters;
+    uint64_t padding_bytes_after_counters;
+#if LLVM_PROFILE_VERSION >= 9
+    uint64_t num_bitmap_bytes;
+    uint64_t padding_bytes_after_bitmap_bytes;
+#endif
     uint64_t names_size;
     uint64_t counters_delta;
+#if LLVM_PROFILE_VERSION >= 9
+    uint64_t bitmap_delta;
+#endif
     uint64_t names_delta;
+#if LLVM_PROFILE_VERSION == 10
+    uint64_t num_vtables;
+    uint64_t vnames_size;
+#endif
     uint64_t value_kind_last;
 };
 
@@ -107,10 +145,14 @@ static int cf_check dump(
     struct llvm_profile_header header = {
         .magic = LLVM_PROFILE_MAGIC,
         .version = LLVM_PROFILE_VERSION,
-        .data_size = (END_DATA - START_DATA) / sizeof(struct llvm_profile_data),
-        .counters_size = (END_COUNTERS - START_COUNTERS) / sizeof(uint64_t),
+        .num_data = DIV_ROUND_UP(END_DATA - START_DATA, sizeof(struct llvm_profile_data)),
+        .num_counters = DIV_ROUND_UP(END_COUNTERS - START_COUNTERS, sizeof(uint64_t)),
         .names_size = END_NAMES - START_NAMES,
+#if LLVM_PROFILE_VERSION >= 8
+        .counters_delta = START_COUNTERS - START_DATA,
+#else
         .counters_delta = (uintptr_t)START_COUNTERS,
+#endif
         .names_delta = (uintptr_t)START_NAMES,
         .value_kind_last = LLVM_PROFILE_NUM_KINDS - 1,
     };

xen/include/xen/xen.lds.h

@@ -81,6 +81,19 @@
   .stab.index 0 : { *(.stab.index) }         \
   .stab.indexstr 0 : { *(.stab.indexstr) }
 
+/* Clang coverage sections. */
+#define LLVM_COV_RW_DATA                                   \
+    DECL_SECTION(__llvm_prf_cnts) { *(__llvm_prf_cnts) }   \
+    DECL_SECTION(__llvm_prf_data) { *(__llvm_prf_data) }   \
+    DECL_SECTION(__llvm_prf_bits) { *(__llvm_prf_bits) }
+
+#define LLVM_COV_RO_DATA                                   \
+    DECL_SECTION(__llvm_prf_names) { *(__llvm_prf_names) }
+
+#define LLVM_COV_DEBUG                                     \
+    DECL_DEBUG(__llvm_covfun, 8)                           \
+    DECL_DEBUG(__llvm_covmap, 8)
+
 /*
  * ELF sections.
  *