[clang-tools-extra] Add flags to dump IR to a file before and after LLVM passes (PR #65179)

[Min-Yih Hsu via cfe-commits]

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@@ -830,6 +831,182 @@ void PrintIRInstrumentation::registerCallbacks(
   }
 }
 
+void DumpIRInstrumentation::registerCallbacks(
+    PassInstrumentationCallbacks &PIC) {
+
+  if (!(shouldDumpBeforeSomePass() || shouldDumpAfterSomePass()))
+    return;
+
+  this->PIC = &PIC;
+
+  PIC.registerBeforeNonSkippedPassCallback(
+      [this](StringRef P, Any IR) { this->pushPass(P, IR); });
+
+  if (shouldDumpBeforeSomePass())
+    PIC.registerBeforeNonSkippedPassCallback(
+        [this](StringRef P, Any IR) { this->dumpBeforePass(P, IR); });
+
+  if (shouldDumpAfterSomePass()) {
+    PIC.registerAfterPassCallback(
+        [this](StringRef P, Any IR, const PreservedAnalyses &) {
+          this->dumpAfterPass(P, IR);
+        });
+  }
+
+  // It is important the the "popPass" callback fires after the dumpAfterPass
+  // callback
+  PIC.registerAfterPassCallback(
+      [this](StringRef P, Any IR, const PreservedAnalyses &) {
+        this->popPass(P);
+      });
+}
+
+void DumpIRInstrumentation::dumpBeforePass(StringRef PassID, Any IR) {
+  if (isIgnored(PassID))
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mshockwave wrote:

somehow I thought the brace on line 870 marks the end of this function, my bad. It's all good now

https://github.com/llvm/llvm-project/pull/65179