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Fix uninitialized signal error #129

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Fix uninitialized signal error #129

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1 change: 1 addition & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ probe is required.
* openocd (version 0.11.0 or above)
* screen
* srecord
* verilator (version 5.024-1 or above)
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I've been using 5.024, is there a difference between that and 5.024-1?

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I believe no difference. However, I saw it being reference here as 5.024-1 unsure if this is an ubuntu thing?

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I would remove the -1 because it is not reported by Verilator itself and it doesn't exist as a tag: https://github.com/verilator/verilator/tags


## Container Guide

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2 changes: 1 addition & 1 deletion vendor/lowrisc_ibex/dv/verilator/pcount/cpp/ibex_pcounts.cc
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Expand Up @@ -53,7 +53,7 @@ static bool has_hpm_counter(int index) {

std::string ibex_pcount_string(bool csv) {
char separator = csv ? ',' : ':';
std::string::size_type longest_name_length;
std::string::size_type longest_name_length = 0;
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Interesting that this wasn't flagged before. What behavior did this cause?

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When trying to build the verilator simulation using:

fusesoc --cores-root=. run --target=sim --tool=verilator --setup --build lowrisc:ibex:demo_system

I got the following error:

ERROR: ../src/lowrisc_dv_verilator_ibex_pcounts_0/cpp/ibex_pcounts.cc: In function ‘std::string ibex_pcount_string(bool)’:
../src/lowrisc_dv_verilator_ibex_pcounts_0/cpp/ibex_pcounts.cc:80:41: warning: ‘longest_name_length’ may be used uninitialized [-Wmaybe-uninitialized]
   80 |       int padding = longest_name_length - ibex_counter_names[i].length();
      |                     ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/lowrisc_dv_verilator_ibex_pcounts_0/cpp/ibex_pcounts.cc:56:26: note: ‘longest_name_length’ was declared here
   56 |   std::string::size_type longest_name_length;
      |                          ^~~~~~~~~~~~~~~~~~~

The full error message when building with the wrong verilator version (5.020) as well is in issue #125

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This is a change to vendored code, which essentially lives in another repository. The original file lives here: https://github.com/lowRISC/ibex/blob/master/dv/verilator/pcount/cpp/ibex_pcounts.cc
Would you like to make a PR in the Ibex repo or shall I do that for you?

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I've made a PR to fix this: lowRISC/ibex#2227


if (!csv) {
longest_name_length = 0;
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