Implement comment filtering in LlvmIrParser (#5389)gh-8526

This is arguably a bit pointless, since most if not all of the comments
in LLVM IR are filtered out as part of directives or attributes, but it
comes up for things like `opt` on LLVM IR with debug info and for DXC
(which is DXIL, but that's LLVM 3.7-era IR).

In any case, this makes things less confusing in those cases by making
the comments filter actually do something, rather than be ignored.

5 files changed, 14 insertions, 0 deletions

diff --git a/lib/llvm-ir.ts b/lib/llvm-ir.ts
index 2dcec50ca..ca4780299 100644
--- a/lib/llvm-ir.ts
+++ b/lib/llvm-ir.ts
@@ -49,6 +49,8 @@ export class LlvmIrParser {
     private attributeDirective: RegExp;
     private moduleMetadata: RegExp;
     private functionAttrs: RegExp;
+    private commentOnly: RegExp;
+    private commentAtEOL: RegExp;
 
     constructor(
         compilerProps,
@@ -72,6 +74,8 @@ export class LlvmIrParser {
         this.attributeDirective = /^attributes #\d+ = { .+ }$/;
         this.functionAttrs = /^; Function Attrs: .+$/;
         this.moduleMetadata = /^((source_filename|target datalayout|target triple) = ".+"|; ModuleID = '.+')$/;
+        this.commentOnly = /^\s*;.*$/;
+        this.commentAtEOL = /\s*;.*$/;
     }
 
     getFileName(debugInfo, scope): string | null {
@@ -174,6 +178,10 @@ export class LlvmIrParser {
             filters.push(this.functionAttrs);
             lineFilters.push(this.attributeAnnotation);
         }
+        if (options.filterComments) {
+            filters.push(this.commentOnly);
+            lineFilters.push(this.commentAtEOL);
+        }
 
         for (const line of irLines) {
             if (line.trim().length === 0) {
@@ -253,6 +261,7 @@ export class LlvmIrParser {
                 filterDebugInfo: !!filters.debugCalls,
                 filterIRMetadata: !!filters.directives,
                 filterAttributes: false,
+                filterComments: !!filters.commentOnly,
                 demangle: !!filters.demangle,
                 // discard value names is handled earlier
             });
diff --git a/static/panes/ir-view.interfaces.ts b/static/panes/ir-view.interfaces.ts
index 640b9012a..a62045b93 100644
--- a/static/panes/ir-view.interfaces.ts
+++ b/static/panes/ir-view.interfaces.ts
@@ -31,4 +31,5 @@ export interface IrState {
     'filter-debug-info'?: boolean;
     'filter-instruction-metadata'?: boolean;
     'filter-attributes'?: boolean;
+    'filter-comments'?: boolean;
 }
diff --git a/static/panes/ir-view.ts b/static/panes/ir-view.ts
index 65996d366..575842fc6 100644
--- a/static/panes/ir-view.ts
+++ b/static/panes/ir-view.ts
@@ -57,6 +57,7 @@ export class Ir extends MonacoPane<monaco.editor.IStandaloneCodeEditor, IrState>
         filterDebugInfo: true,
         filterIRMetadata: true,
         filterAttributes: true,
+        filterComments: true,
         noDiscardValueNames: true,
         demangle: true,
     };
@@ -183,6 +184,7 @@ export class Ir extends MonacoPane<monaco.editor.IStandaloneCodeEditor, IrState>
             filterDebugInfo: filters['filter-debug-info'],
             filterIRMetadata: filters['filter-instruction-metadata'],
             filterAttributes: filters['filter-attributes'],
+            filterComments: filters['filter-comments'],
             noDiscardValueNames: options['-fno-discard-value-names'],
             demangle: options['demangle-symbols'],
         };
diff --git a/types/compilation/ir.interfaces.ts b/types/compilation/ir.interfaces.ts
index 060422ae0..c39e21f7c 100644
--- a/types/compilation/ir.interfaces.ts
+++ b/types/compilation/ir.interfaces.ts
@@ -26,6 +26,7 @@ export type LLVMIrBackendOptions = {
     filterDebugInfo: boolean;
     filterIRMetadata: boolean;
     filterAttributes: boolean;
+    filterComments: boolean;
     noDiscardValueNames?: boolean;
     demangle: boolean;
 };
diff --git a/views/templates/panes/ir.pug b/views/templates/panes/ir.pug
index 80f3342ad..ff140dca4 100644
--- a/views/templates/panes/ir.pug
+++ b/views/templates/panes/ir.pug
@@ -22,6 +22,7 @@ mixin optionButton(bind, isActive, text, title)
         +optionButton("filter-debug-info", true, "Hide Debug Info", "Filter debug info intrinsics")
         +optionButton("filter-instruction-metadata", true, "Hide Instruction Metadata", "Filter all IR metadata")
         +optionButton("filter-attributes", true, "Filter Attribute Groups", "Filter attribute groups")
+        +optionButton("filter-comments", true, "Hide Comments", "Filter comments")
         //- +optionButton("library-functions", true, "Filter Library Functions", "Filter library functions")
     .btn-group.btn-group-sm(role="group")
       button.btn.btn-sm.btn-light.cfg(title="Open Control Flow Graph")