Commit bef16ab4 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg: Diagnose referenced labels that have not been emitted 



Currently, a jump to a label that is not defined anywhere will
be emitted not be relocated.  This results in a jump to a random
jump target.  With tcg debugging, print a diagnostic to the -d op
file and abort.

This could help debug or detect errors like
c2d9644e ("target/arm: Fix crash on conditional instruction in an IT block")

Reported-by: default avatarRoman Kapl <code@rkapl.cz>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent a044e3de

tcg/tcg-op.h

+1 −0
Original line number Diff line number Diff line
@@ -255,6 +255,7 @@ static inline void tcg_gen_op6ii_i64(TCGOpcode opc, TCGv_i64 a1, TCGv_i64 a2, 


static inline void gen_set_label(TCGLabel *l)

{

    l->present = 1;

    tcg_gen_op1(INDEX_op_set_label, label_arg(l));

}

tcg/tcg.c

+23 −0
Original line number Diff line number Diff line
@@ -305,6 +305,9 @@ TCGLabel *gen_new_label(void) 
    *l = (TCGLabel){

        .id = s->nb_labels++

    };

#ifdef CONFIG_DEBUG_TCG

    QSIMPLEQ_INSERT_TAIL(&s->labels, l, next);

#endif



    return l;

}
@@ -1092,6 +1095,9 @@ void tcg_func_start(TCGContext *s) 


    QTAILQ_INIT(&s->ops);

    QTAILQ_INIT(&s->free_ops);

#ifdef CONFIG_DEBUG_TCG

    QSIMPLEQ_INIT(&s->labels);

#endif

}



static inline TCGTemp *tcg_temp_alloc(TCGContext *s)
@@ -3841,6 +3847,23 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb) 
    }

#endif



#ifdef CONFIG_DEBUG_TCG

    /* Ensure all labels referenced have been emitted.  */

    {

        TCGLabel *l;

        bool error = false;



        QSIMPLEQ_FOREACH(l, &s->labels, next) {

            if (unlikely(!l->present) && l->refs) {

                qemu_log_mask(CPU_LOG_TB_OP,

                              "$L%d referenced but not present.\n", l->id);

                error = true;

            }

        }

        assert(!error);

    }

#endif



#ifdef CONFIG_PROFILER

    atomic_set(&prof->opt_time, prof->opt_time - profile_getclock());

#endif

tcg/tcg.h

+9 −3
Original line number Diff line number Diff line
@@ -244,16 +244,21 @@ typedef struct TCGRelocation { 
    intptr_t addend;

} TCGRelocation; 



typedef struct TCGLabel {

typedef struct TCGLabel TCGLabel;

struct TCGLabel {

    unsigned present : 1;

    unsigned has_value : 1;

    unsigned id : 15;

    unsigned id : 14;

    unsigned refs : 16;

    union {

        uintptr_t value;

        tcg_insn_unit *value_ptr;

        TCGRelocation *first_reloc;

    } u;

} TCGLabel;

#ifdef CONFIG_DEBUG_TCG

    QSIMPLEQ_ENTRY(TCGLabel) next;

#endif

};



typedef struct TCGPool {

    struct TCGPool *next;
@@ -685,6 +690,7 @@ struct TCGContext { 
#endif



#ifdef CONFIG_DEBUG_TCG

    QSIMPLEQ_HEAD(, TCGLabel) labels;

    int temps_in_use;

    int goto_tb_issue_mask;

#endif