Debug log

To check whether the Sigasi extension started successfully, you should navigate to Sigasi’s output view. This can be done through the Command Palette (Ctrl+Shift+P) and select Sigasi: Open log. Note that this option is only available once an HDL file was opened.

The output for Sigasi should say Language client connected from ...

The logs in the Sigasi output view contain possible errors from client and server. If errors are present you’re advised to copy them and include them in your email to support+vscode@sigasi.com.

SLF4J errors

The following error messages in the Output View can be safely ignored.

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

OutOfMemoryError: Java heap space

If the Java heap space goes out of memory you will see a java.lang.OutOfMemoryError: Java heap space in the log.

To avoid this, go to the settings (Ctrl+Shift+P > Preferences: Open Settings (UI) > Sigasi). Here you can set the Sigasi > Server: Arguments. Increase the value for Xmx to more than the default 3g.

The heap space setting is identical to the one used in Sigasi Studio.


Project configuration

On some occasions, we might ask for you to share the project configuration. This configuration can be obtained through the Command Palette (Ctrl+Shift+P) where you run the command Sigasi: Get the current project description and select the project you’re working on.

This generates two JSON files project.server.json and project.client.json that contain information sent to the server.

Note: these JSON files contain file names from your project so only send them to us if you’re allowed to do so.

Server logs

On some occasions we might ask you to share the server logs.

Before obtaining the server logs it’s best to enable debug logging. For more detailed logging, open the settings and change Sigasi > Server > Log: Level to debug.

The server logs are in ~/.config/Code/logs/[datetime]/exthost1/output_logging_[datetime]/[N]-Sigasi.log.

  • For each occurrence of [datetime], choose the most recent directory available
  • N depends on the number of extensions present

Note: these logs contain file names from your project so only send them to us if you’re allowed to do so.

Heap dump

For debugging purposes, a heap dump might be useful. A command is available to capture a heap dump from within the Command Palette: Sigasi: capture heap dump.


On some occasions, we might ask you to share a profile of the extension. To do so, you can use the command Sigasi: Start profiling.

Performance monitoring

On some occasions, we might ask you to share a performance trace.

To start the performance trace capture, use the command Sigasi: Start performance logging.

After going through the activities on which to check performance, use the command Sigasi: Stop performance logging. This will open a file browser allowing to save a Trace-YYYY-MM-DD-HH-MM-SS.json file. This file contains the performance log and should be sent to our support.

Semantic Coloring

The Sigasi extension supports semantic coloring, however, some VS Code themes might not support it yet.

  • In a theme that supports semantic coloring, you’ll see that e.g. port, signal and type names have a color that is different from the language keywords.
  • In a theme that does not support semantic coloring, names like those of a port, signal or type will have the default text color.

User defined code snippets

VS Code supports user defined code snippets as explained here. To add snippets yourself, follow the steps below.

The Sigasi extension currently contains only two snippets: one for entity and one for module.

  • Open the Command Palette (Ctrl+Shift+P) and type Snippets
  • Select Preferences: Configure User Snippets
  • Type vhdl or systemverilog to open the corresponding JSON file where you can add your snippet like the examples below.

VHDL snippet example

    // Place your snippets for vhdl here.
    "package declaration": {
        "prefix": "package",
        "body": [
            "package ${1:name} is",
            "end package $1;"
        "description": "Insert package declaration"

SystemVerilog snippet example

    // Place your snippets for systemverilog here.
    "always posedge clk": {
        "prefix": "always",
        "body": [
            "always @(posedge ${1:clk}) begin",
        "description": "Insert an always block with posedge clock"