[clang] [llvm] [clang][ssaf] Implement JSON format for CallGraph summary (PR #189681)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-darwin` running on `doug-worker-3` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/23/builds/18953

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Analysis/Scalable/call-graph.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
rm -rf /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# executed command: rm -rf /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# note: command had no output on stdout or stderr
# RUN: at line 2
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -cc1 -internal-isystem /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/lib/clang/23/include -nostdsysteminc -fsyntax-only /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp    --ssaf-extract-summaries=CallGraph    --ssaf-tu-summary-file=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/clang -cc1 -internal-isystem /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/lib/clang/23/include -nostdsysteminc -fsyntax-only /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp --ssaf-extract-summaries=CallGraph --ssaf-tu-summary-file=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# note: command had no output on stdout or stderr
# RUN: at line 5
/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp --match-full-lines --input-file=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# executed command: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/bin/FileCheck /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp --match-full-lines --input-file=/Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# .---command stderr------------
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp:13:15: error: CHECK-DAG: expected string not found in input
# | // CHECK-DAG: "pretty_name": "caller()",
# |               ^
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json:7:21: note: scanning from here
# |  "entity_summary": {
# |                     ^
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json:14:2: note: possible intended match here
# |  "pretty_name": "polymorphic(Base &)",
# |  ^
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp:23:15: error: CHECK-DAG: expected string not found in input
# | // CHECK-DAG: "pretty_name": "polymorphic(Base &)",
# |               ^
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json:24:21: note: scanning from here
# |  "entity_summary": {
# |                     ^
# | /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json:35:2: note: possible intended match here
# |  "pretty_name": "caller()",
# |  ^
# | 
# | Input file: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/build/tools/clang/test/Analysis/Scalable/Output/call-graph.cpp.tmp.summary.json
# | Check file: /Volumes/RAMDisk/buildbot-root/x86_64-darwin/llvm-project/clang/test/Analysis/Scalable/call-graph.cpp
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1: { 
# |            2:  "data": [ 
# |            3:  { 
# |            4:  "summary_data": [ 
# |            5:  { 
# |            6:  "entity_id": 1, 
# |            7:  "entity_summary": { 
...

```

</details>

https://github.com/llvm/llvm-project/pull/189681