objtool: Get rid of reloc->jump_table_start

Rework the jump table logic slightly so 'jump_table_start' is no longer
needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 40.37G
- After:  peak heap memory consumption: 38.64G

Link: https://lore.kernel.org/r/e1602ed8a6171ada3cfac0bd8449892ec82bd188.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 745487dda43241cd15cb7351a99fb7e9173a9e1d..7fb6467178cb192bb86432dc9f48a5bd5d1be6a3 100644 (file)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1989,13 +1989,14 @@ out:
 }
 
 static int add_jump_table(struct objtool_file *file, struct instruction *insn,
-                           struct reloc *table)
+                         struct reloc *next_table)
 {
-       struct reloc *reloc = table;
-       struct instruction *dest_insn;
-       struct alternative *alt;
        struct symbol *pfunc = insn_func(insn)->pfunc;
+       struct reloc *table = insn_jump_table(insn);
+       struct instruction *dest_insn;
        unsigned int prev_offset = 0;
+       struct reloc *reloc = table;
+       struct alternative *alt;
 
        /*
         * Each @reloc is a switch table relocation which points to the target
@@ -2004,7 +2005,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
        for_each_reloc_from(table->sec, reloc) {
 
                /* Check for the end of the table: */
-               if (reloc != table && reloc->jump_table_start)
+               if (reloc != table && reloc == next_table)
                        break;
 
                /* Make sure the table entries are consecutive: */
@@ -2119,29 +2120,39 @@ static void mark_func_jump_tables(struct objtool_file *file,
                        continue;
 
                reloc = find_jump_table(file, func, insn);
-               if (reloc) {
-                       reloc->jump_table_start = true;
+               if (reloc)
                        insn->_jump_table = reloc;
-               }
        }
 }
 
 static int add_func_jump_tables(struct objtool_file *file,
                                  struct symbol *func)
 {
-       struct instruction *insn;
-       int ret;
+       struct instruction *insn, *insn_t1 = NULL, *insn_t2;
+       int ret = 0;
 
        func_for_each_insn(file, func, insn) {
                if (!insn_jump_table(insn))
                        continue;
 
-               ret = add_jump_table(file, insn, insn_jump_table(insn));
+               if (!insn_t1) {
+                       insn_t1 = insn;
+                       continue;
+               }
+
+               insn_t2 = insn;
+
+               ret = add_jump_table(file, insn_t1, insn_jump_table(insn_t2));
                if (ret)
                        return ret;
+
+               insn_t1 = insn_t2;
        }
 
-       return 0;
+       if (insn_t1)
+               ret = add_jump_table(file, insn_t1, NULL);
+
+       return ret;
 }
 
 /*

diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index be08b32a93ee1ace905dba8828e46b64cd410cf5..60686f746c9ec194373e89a2e44ceb05406621b0 100644 (file)
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -75,7 +75,6 @@ struct reloc {
        struct section *sec;
        struct symbol *sym;
        struct list_head sym_reloc_entry;
-       bool jump_table_start;
 };
 
 struct elf {