runtime_loader: Add support for DT_GNU_HASH.

This is an alternative to DT_HASH (SystemV/SVR4 hash tables.) Notably,
it uses a Bloom filter to allow an entire image to be skipped
at once rather than searching the actual symbol hash.

We don't currently build anything with DT_GNU_HASH support.
You can test this by adding -Wl,--hash-style=both to HAIKU_LINKFLAGS.
(It seems to increase image sizes by not too much: libroot goes
from 1347139 to 1367691 bytes (20.55 KB) in my build.)

Change-Id: I4a91276490fcd136db175833ee48b36e06ceed47
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7855
Reviewed-by: waddlesplash <[email protected]>

headers/os/kernel/elf.h

@@ -544,6 +544,8 @@ typedef struct {
 #define DT_PREINIT_ARRAY	32	/* preinitialization array */
 #define DT_PREINIT_ARRAYSZ	33	/* preinitialization array size */
 
+#define	DT_GNU_HASH		0x6ffffef5	/* GNU-style hash table */
+
 #define DT_VERSYM       0x6ffffff0	/* symbol version table */
 #define DT_VERDEF		0x6ffffffc	/* version definition table */
 #define DT_VERDEFNUM	0x6ffffffd	/* number of version definitions */

headers/private/runtime_loader/runtime_loader.h

@@ -107,16 +107,32 @@ typedef struct image_t {
 	addr_t				term_routine;
 	addr_t 				dynamic_ptr; 	// pointer to the dynamic section
 
-	// pointer to symbol participation data structures
+	// needed images
+	uint32				num_needed;
+	struct image_t		**needed;
+
+	// symbol participation data structures
 	uint32				*symhash;
 	elf_sym				*syms;
 	char				*strtab;
+	struct {
+		uint32			mask_words_count_mask;
+		uint32			shift2;
+		uint32			bucket_count;
+		elf_addr		*bloom;
+		uint32			*buckets;
+		uint32			*chain0;
+	} gnuhash;
+
+	// relocation information
 	elf_rel				*rel;
 	int					rel_len;
 	elf_rela			*rela;
 	int					rela_len;
 	elf_rel				*pltrel;
 	int					pltrel_len;
+
+	// init/term functions
 	addr_t				*init_array;
 	int					init_array_len;
 	addr_t				*preinit_array;
@@ -124,11 +140,6 @@ typedef struct image_t {
 	addr_t				*term_array;
 	int					term_array_len;
 
-	unsigned			dso_tls_id;
-
-	uint32				num_needed;
-	struct image_t		**needed;
-
 	// versioning related structures
 	uint32				num_version_definitions;
 	elf_verdef			*version_definitions;
@@ -138,6 +149,9 @@ typedef struct image_t {
 	elf_version_info	*versions;
 	uint32				num_versions;
 
+	// thread-local storage
+	unsigned			dso_tls_id;
+
 #ifdef __cplusplus
 	elf_sym*			(*find_undefined_symbol)(struct image_t* rootImage,
 							struct image_t* image,