Data Flow Analysis

kripashankar kripa82@yahoo.com
Fri Jul 9 16:35:00 GMT 2004


Hi all

I wrote a function "DataFlowOutput" to get the use-def
and def-use statistics of the registers.

static void DataFlowOutput(void)
{
     struct df *df;

      df = df_init ();

      df_analyse (df, 0, DF_ALL);

      df_dump (df, DF_ALL, stderr);

      df_finish (df);
}

This function is invoked before the final pass i.e
before the RTL gets converted to assembly..

but the function is not printing the statistics..
It outputs the following

Dataflow summary:
n_regs = 66, n_defs = 0, n_uses = 0, n_bbs = 17
Reaching defs:
bb 0 in
bb 0 gen
bb 0 kill
bb 0 out
bb 1 in
bb 1 gen

Use-def chains:
Reaching uses:
bb 0 in
bb 0 gen
bb 0 kill
bb 0 out
bb 1 in
bb 1 gen
bb 1 kill
bb 1 out

Def-use chains:
Live regs:
bb 0 in
bb 0 use
bb 0 def
bb 0 out
bb 1 in
bb 1 use
bb 1 def
bb 1 out

Iam trying to get the definition and use of each
register in the program and their instrn
id(INSN_UID)..
I would appreciate any kind of help.

regards
kripa



		
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