Adding Fortran call graph collector by gomfol12 · Pull Request #115 · tudasc/MetaCG

gomfol12 · 2026-02-05T15:47:07Z

This adds a call graph collector for Fortran. The collector is implemented as a flang plugin and generates a call graph from source-level. See the tests for a list of language features this plugin covers.

This pull request is quite large, but it is not really possible splitting it in multiply requests without pushing broken code. The tests could be separate into a different pull request, but they are tightly coupled with the collector and would fail without it, so I think keeping it in one pull request makes sense.

What this adds:

new directory cgfcollector that includes flang plugin, tests, tools, etc.
flang plugin that generates call graph in metacg format.
two wrapper script cgfcollector_wrapper.sh and cgfcollector_comp_wrapper.sh that simplify running the plugin.
cgCompare tool: for comparing two call graphs (can be replaced with cgdiff)
another test runner

How to run: see cgfcollector/README.md

The commit history is a mess, and I don't know how strongly you value a clean git history and if I should clean this up.

pearzt

Thanks a lot for all the work, the structure looks really good. I have some initial comments, but I will try to do a more in-depth review soon.

cmake/FlangLLVM.cmake

cgfcollector/README.md

cgfcollector/CMakeLists.txt

cgfcollector/tools/cgCompare.cpp

jplehr

Thank you for working on this.

I did an initial brief pass, please go through the comments and address them.

One more question: Does this PR as-is already run CI pipelines? If not, please add it to the CI pipelines as appropriate.

cgfcollector/include/Edge.h

cgfcollector/include/edge.h

jplehr · 2026-02-13T10:15:04Z

cgfcollector/include/edge.h

+using namespace Fortran::semantics;
+using namespace Fortran::parser;
+using namespace metacg;
+


This should probably live inside the metacg namespace?
If not, it should likely live in its own namespace.

What are others' opinions here?

We don't really have a common scheme for namespaces. Headers that are used for more than one tool (e.g., public-facing headers) should use metacg::*, I guess, but that's not the case here.

Until we agree on a policy, I would leave it to @gomfol12 whether to use a namespace. If we want to use a namespace, I'd suggest metacg:: or metacg::cgfcollector.

jplehr · 2026-02-13T10:23:00Z

cgfcollector/src/Main.cpp

+    dot::DotGenerator dotGen(cg);
+    dotGen.generate();
+
+    std::unique_ptr<llvm::raw_pwrite_stream> dotfile = ::createOutputFile(getInstance(), getCurrentFile(), "dot");


This can be problematic in parallel CI runs

I think we should separate the concerns between call graph generation and visualization. cgfcollector produces the call graph. If the user want a visualization, they can use your dot export tool for this (which is a nice addition, btw).

jplehr · 2026-02-13T10:23:31Z

cgfcollector/src/Main.cpp

+
+    std::string cgString = dumpCG();
+
+    std::unique_ptr<llvm::raw_pwrite_stream> file = ::createOutputFile(getInstance(), getCurrentFile(), "");


This can be problematic in parallel CI runs

jplehr · 2026-02-13T10:28:22Z

cgfcollector/tools/visuel.cpp

Should this be named visual?

Is this limited to the Fortran support? I would assume this can be factored out into another PR and put in as a general tool.
Other people's thoughts?

I agree that this is something that should extracted into a separate PR.

cgfcollector/CMakeLists.txt

jplehr · 2026-02-13T10:30:59Z

cmake/FlangLLVM.cmake

+message(STATUS "Using MLIR version: ${MLIR_VERSION}")
+
+function(add_flang target)
+  target_compile_definitions(${target} PRIVATE FLANG_LITTLE_ENDIAN)


Is this always the case? I tend to believe that this may be platform specific?
If so, let's put a TODO / XXX / Comment here.

pearzt · 2026-02-17T10:13:49Z

Please rebase this onto the most current devel.

…ction

… for debugging graph edges

… some tests.

… not inserted into cg

… instead of node ids

…first

pearzt · 2026-02-17T16:42:08Z

cgfcollector/src/Main.cpp

+    generateCG(getParsing().parseTree(), getCurrentFile());
+
+    std::string cgString = dumpCG();
+    std::unique_ptr<llvm::raw_pwrite_stream> file = ::createOutputFile(getInstance(), getCurrentFile(), "json");


Please use the MCGWriter infrastructure for file output. For an example how to use this, have a look at tools/cgconvert/CGConvert.cpp.

pearzt · 2026-02-17T16:43:56Z

cgfcollector/src/Main.cpp

+    dot::DotGenerator dotGen(cg);
+    dotGen.generate();
+
+    std::unique_ptr<llvm::raw_pwrite_stream> dotfile = ::createOutputFile(getInstance(), getCurrentFile(), "dot");


I think we should separate the concerns between call graph generation and visualization. cgfcollector produces the call graph. If the user want a visualization, they can use your dot export tool for this (which is a nice addition, btw).

pearzt requested changes Feb 6, 2026

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jplehr reviewed Feb 13, 2026

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gomfol12 added 27 commits February 17, 2026 16:00

add/modified cmakefiles to add cgfcollector subproject

f1d3ddb

WIP: add simple function parsing and integrated graphlib

828ac1f

add wrapper and simple test script

1171889

add main function mangling for fortran to correctly identify main fun…

7a75d16

…ction

add simple test case 1

ea1f6b5

added test case using a module

dfd7789

fix typo in CMakeLists.txt and add precompiled headers

c96cab8

rework main to construct CG and set hasBody property accordingly

0a6f06a

tests now ignore _MetaCG part in json file

adbfaf6

update simple_01 test for MetaCG format version 3

7cc5b80

add some tests

8806ae2

tests ignore the origin field as this differ from machines

d29fb75

nesting test for calls with %

4067750

function calls with % are now correctly parsed and generate dot files…

c67d045

… for debugging graph edges

WIP: impl parsing for function overriding in derived types. And broke…

25cfa21

… some tests.

fix and cleanup the ProcedureDesignator parsing

b0ac1f1

add -dot option to configure .dot generation

2df288f

more tests

7d80405

WIP: impl finalizers parsing. Still overestimates

7e59c70

fix: problem with deferred keyword in abstract type where edges where…

43df1b3

… not inserted into cg

simple 05 add output.json

555a4d1

impl operator overloading parsing, WIP: defined operator parsing

55188a8

better test case for operator overloading and defined operators

8eeaab0

better test case for finalizers

7d4bcef

tests: impl dedicated CG compare tool using node names to compare CGs…

a8cd7ab

… instead of node ids

add cmake managed tests for multi file tests

208bb6d

renamed test case 6 to operator

1d91598

gomfol12 added 26 commits February 17, 2026 16:01

refactor

13d762c

add documentation

998274c

refactor and add documentation

3a48582

use function struct for currentFunctions vector

9a76262

doc and refector

56458a2

refactor in individual files

0c9782c

variableTracking doc

f269343

ParseTreeVisitor more doc

f9a31bc

edgeManager refactor

2570939

edgeManager refactor

e5ef515

rename type typeSymbol

4e7ace6

change to remove in handleTrackedVars

1130db0

removed const_cast and resolved auto for clarity

35f7387

add doc in tool scripts

9efa7ac

updated cgfcollector README

e743f97

removed duplicate comment

c092fcf

cmake uncomment/removed lines

b5503fc

README: add context and fix typo

3e8de05

migration: CGCompare to CGDiff

9c912e5

removed CGCompare

d84aef7

simplify test script and integrate in cmake

2d0dfdd

cmake add flangFrontendTool find

9602d67

Filename capitalization and license headers

2570553

removed using namespace from header files and project-local includes …

59e8b74

…first

use upper case type names

056dfe6

comment style

ed5d7ff

gomfol12 force-pushed the fortran_collector branch from 01f3d3f to ed5d7ff Compare February 17, 2026 15:16

Consistent naming for cgfcollector

a5f9ffe

pearzt requested changes Feb 17, 2026

View reviewed changes

pearzt assigned gomfol12 Feb 17, 2026


		std::string cgString = dumpCG();

		std::unique_ptr<llvm::raw_pwrite_stream> file = ::createOutputFile(getInstance(), getCurrentFile(), "");

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gomfol12 commented Feb 5, 2026

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pearzt commented Feb 17, 2026

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