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-rw-r--r--tcg/tcg.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/tcg/tcg.c b/tcg/tcg.c
index ccfcd1abe1..eb595ce6fd 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -28,6 +28,9 @@
#include "config.h"
+/* Define to jump the ELF file used to communicate with GDB. */
+#undef DEBUG_JIT
+
#if !defined(CONFIG_DEBUG_TCG) && !defined(NDEBUG)
/* define it to suppress various consistency checks (faster) */
#define NDEBUG
@@ -45,6 +48,18 @@
#include "cpu.h"
#include "tcg-op.h"
+
+#if TCG_TARGET_REG_BITS == 64
+# define ELF_CLASS ELFCLASS64
+#else
+# define ELF_CLASS ELFCLASS32
+#endif
+#ifdef HOST_WORDS_BIGENDIAN
+# define ELF_DATA ELFDATA2MSB
+#else
+# define ELF_DATA ELFDATA2LSB
+#endif
+
#include "elf.h"
#if defined(CONFIG_USE_GUEST_BASE) && !defined(TCG_TARGET_HAS_GUEST_BASE)
@@ -57,6 +72,10 @@ static void tcg_target_qemu_prologue(TCGContext *s);
static void patch_reloc(uint8_t *code_ptr, int type,
tcg_target_long value, tcg_target_long addend);
+static void tcg_register_jit_int(void *buf, size_t size,
+ void *debug_frame, size_t debug_frame_size)
+ __attribute__((unused));
+
/* Forward declarations for functions declared and used in tcg-target.c. */
static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str);
static void tcg_out_ld(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
@@ -2231,3 +2250,178 @@ void tcg_dump_info(FILE *f, fprintf_function cpu_fprintf)
cpu_fprintf(f, "[TCG profiler not compiled]\n");
}
#endif
+
+#ifdef ELF_HOST_MACHINE
+/* The backend should define ELF_HOST_MACHINE to indicate both what value to
+ put into the ELF image and to indicate support for the feature. */
+
+/* Begin GDB interface. THE FOLLOWING MUST MATCH GDB DOCS. */
+typedef enum {
+ JIT_NOACTION = 0,
+ JIT_REGISTER_FN,
+ JIT_UNREGISTER_FN
+} jit_actions_t;
+
+struct jit_code_entry {
+ struct jit_code_entry *next_entry;
+ struct jit_code_entry *prev_entry;
+ const void *symfile_addr;
+ uint64_t symfile_size;
+};
+
+struct jit_descriptor {
+ uint32_t version;
+ uint32_t action_flag;
+ struct jit_code_entry *relevant_entry;
+ struct jit_code_entry *first_entry;
+};
+
+void __jit_debug_register_code(void) __attribute__((noinline));
+void __jit_debug_register_code(void)
+{
+ asm("");
+}
+
+/* Must statically initialize the version, because GDB may check
+ the version before we can set it. */
+struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
+
+/* End GDB interface. */
+
+static int find_string(const char *strtab, const char *str)
+{
+ const char *p = strtab + 1;
+
+ while (1) {
+ if (strcmp(p, str) == 0) {
+ return p - strtab;
+ }
+ p += strlen(p) + 1;
+ }
+}
+
+static void tcg_register_jit_int(void *buf, size_t buf_size,
+ void *debug_frame, size_t debug_frame_size)
+{
+ static const char strings[64] =
+ "\0"
+ ".text\0"
+ ".debug_frame\0"
+ ".symtab\0"
+ ".strtab\0"
+ "code_gen_buffer";
+
+ struct ElfImage {
+ ElfW(Ehdr) ehdr;
+ ElfW(Phdr) phdr;
+ ElfW(Shdr) shdr[5];
+ ElfW(Sym) sym[1];
+ char str[64];
+ };
+
+ /* We only need a single jit entry; statically allocate it. */
+ static struct jit_code_entry one_entry;
+
+ size_t img_size = sizeof(struct ElfImage) + debug_frame_size;
+ struct ElfImage *img = g_malloc0(img_size);
+
+ img->ehdr.e_ident[EI_MAG0] = ELFMAG0;
+ img->ehdr.e_ident[EI_MAG1] = ELFMAG1;
+ img->ehdr.e_ident[EI_MAG2] = ELFMAG2;
+ img->ehdr.e_ident[EI_MAG3] = ELFMAG3;
+ img->ehdr.e_ident[EI_CLASS] = ELF_CLASS;
+ img->ehdr.e_ident[EI_DATA] = ELF_DATA;
+ img->ehdr.e_ident[EI_VERSION] = EV_CURRENT;
+ img->ehdr.e_type = ET_EXEC;
+ img->ehdr.e_machine = ELF_HOST_MACHINE;
+ img->ehdr.e_version = EV_CURRENT;
+ img->ehdr.e_phoff = offsetof(struct ElfImage, phdr);
+ img->ehdr.e_shoff = offsetof(struct ElfImage, shdr);
+ img->ehdr.e_ehsize = sizeof(ElfW(Shdr));
+ img->ehdr.e_phentsize = sizeof(ElfW(Phdr));
+ img->ehdr.e_phnum = 1;
+ img->ehdr.e_shentsize = sizeof(img->shdr[0]);
+ img->ehdr.e_shnum = ARRAY_SIZE(img->shdr);
+ img->ehdr.e_shstrndx = ARRAY_SIZE(img->shdr) - 1;
+
+ img->phdr.p_type = PT_LOAD;
+ img->phdr.p_offset = (char *)buf - (char *)img;
+ img->phdr.p_vaddr = (ElfW(Addr))buf;
+ img->phdr.p_paddr = img->phdr.p_vaddr;
+ img->phdr.p_filesz = 0;
+ img->phdr.p_memsz = buf_size;
+ img->phdr.p_flags = PF_X;
+
+ memcpy(img->str, strings, sizeof(img->str));
+
+ img->shdr[0].sh_type = SHT_NULL;
+
+ /* Trick: The contents of code_gen_buffer are not present in this fake
+ ELF file; that got allocated elsewhere, discontiguously. Therefore
+ we mark .text as SHT_NOBITS (similar to .bss) so that readers will
+ not look for contents. We can record any address at will. */
+ img->shdr[1].sh_name = find_string(img->str, ".text");
+ img->shdr[1].sh_type = SHT_NOBITS;
+ img->shdr[1].sh_flags = SHF_EXECINSTR | SHF_ALLOC;
+ img->shdr[1].sh_addr = (ElfW(Addr))buf;
+ img->shdr[1].sh_size = buf_size;
+
+ img->shdr[2].sh_name = find_string(img->str, ".debug_frame");
+ img->shdr[2].sh_type = SHT_PROGBITS;
+ img->shdr[2].sh_offset = sizeof(*img);
+ img->shdr[2].sh_size = debug_frame_size;
+ memcpy(img + 1, debug_frame, debug_frame_size);
+
+ img->shdr[3].sh_name = find_string(img->str, ".symtab");
+ img->shdr[3].sh_type = SHT_SYMTAB;
+ img->shdr[3].sh_offset = offsetof(struct ElfImage, sym);
+ img->shdr[3].sh_size = sizeof(img->sym);
+ img->shdr[3].sh_info = ARRAY_SIZE(img->sym);
+ img->shdr[3].sh_link = img->ehdr.e_shstrndx;
+ img->shdr[3].sh_entsize = sizeof(ElfW(Sym));
+
+ img->shdr[4].sh_name = find_string(img->str, ".strtab");
+ img->shdr[4].sh_type = SHT_STRTAB;
+ img->shdr[4].sh_offset = offsetof(struct ElfImage, str);
+ img->shdr[4].sh_size = sizeof(img->str);
+
+ img->sym[0].st_name = find_string(img->str, "code_gen_buffer");
+ img->sym[0].st_info = ELF_ST_INFO(STB_GLOBAL, STT_FUNC);
+ img->sym[0].st_shndx = 1;
+ img->sym[0].st_value = (ElfW(Addr))buf;
+ img->sym[0].st_size = buf_size;
+
+#ifdef DEBUG_JIT
+ /* Enable this block to be able to debug the ELF image file creation.
+ One can use readelf, objdump, or other inspection utilities. */
+ {
+ FILE *f = fopen("/tmp/qemu.jit", "w+b");
+ if (f) {
+ if (fwrite(img, img_size, 1, f) != buf_size) {
+ /* Avoid stupid unused return value warning for fwrite. */
+ }
+ fclose(f);
+ }
+ }
+#endif
+
+ one_entry.symfile_addr = img;
+ one_entry.symfile_size = img_size;
+
+ __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
+ __jit_debug_descriptor.relevant_entry = &one_entry;
+ __jit_debug_descriptor.first_entry = &one_entry;
+ __jit_debug_register_code();
+}
+#else
+/* No support for the feature. Provide the entry point expected by exec.c. */
+
+static void tcg_register_jit_int(void *buf, size_t size,
+ void *debug_frame, size_t debug_frame_size)
+{
+}
+
+void tcg_register_jit(void *buf, size_t buf_size)
+{
+}
+#endif /* ELF_HOST_MACHINE */
generated by cgit v1.2.1 (git 2.18.0) at 2024-07-06 11:32:08 +0000