[clang][analyzer] Format macro expansions (llvm#156046)

Fixes llvm#154743

Author: ankurkraj

clang/include/clang/Analysis/MacroExpansionContext.h

@@ -96,6 +96,13 @@ class MacroExpansionContext {
   std::optional<StringRef>
   getOriginalText(SourceLocation MacroExpansionLoc) const;
 
+  /// \param MacroExpansionLoc Must be the expansion location of a macro.
+  /// \return A formatted representation of the textual representation of the
+  ///         token sequence which was substituted in place of the macro.
+  ///         If no macro was expanded at that location, returns std::nullopt.
+  std::optional<StringRef>
+  getFormattedExpandedText(SourceLocation MacroExpansionLoc) const;
+
   LLVM_DUMP_METHOD void dumpExpansionRangesToStream(raw_ostream &OS) const;
   LLVM_DUMP_METHOD void dumpExpandedTextsToStream(raw_ostream &OS) const;
   LLVM_DUMP_METHOD void dumpExpansionRanges() const;
@@ -106,6 +113,7 @@ class MacroExpansionContext {
   using MacroExpansionText = SmallString<40>;
   using ExpansionMap = llvm::DenseMap<SourceLocation, MacroExpansionText>;
   using ExpansionRangeMap = llvm::DenseMap<SourceLocation, SourceLocation>;
+  using FormattedExpansionMap = llvm::DenseMap<SourceLocation, std::string>;
 
   /// Associates the textual representation of the expanded tokens at the given
   /// macro expansion location.
@@ -115,6 +123,9 @@ class MacroExpansionContext {
   /// substitution starting from a given macro expansion location.
   ExpansionRangeMap ExpansionRanges;
 
+  /// Caches formatted macro expansions keyed by expansion location.
+  mutable FormattedExpansionMap FormattedExpandedTokens;
+
   Preprocessor *PP = nullptr;
   SourceManager *SM = nullptr;
   const LangOptions &LangOpts;

clang/lib/Analysis/CMakeLists.txt

@@ -40,6 +40,7 @@ add_clang_library(clangAnalysis
   clangAST
   clangASTMatchers
   clangBasic
+  clangFormat
   clangLex
 
   DEPENDS

clang/lib/Analysis/MacroExpansionContext.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Analysis/MacroExpansionContext.h"
+#include "clang/Format/Format.h"
 #include "llvm/Support/Debug.h"
 #include <optional>
 
@@ -132,6 +133,35 @@ MacroExpansionContext::getOriginalText(SourceLocation MacroExpansionLoc) const {
       LangOpts);
 }
 
+std::optional<StringRef> MacroExpansionContext::getFormattedExpandedText(
+    SourceLocation MacroExpansionLoc) const {
+  std::optional<StringRef> ExpandedText = getExpandedText(MacroExpansionLoc);
+  if (!ExpandedText)
+    return std::nullopt;
+
+  auto [It, Inserted] =
+      FormattedExpandedTokens.try_emplace(MacroExpansionLoc, "");
+  if (!Inserted)
+    return StringRef(It->getSecond());
+
+  clang::format::FormatStyle Style = clang::format::getLLVMStyle();
+
+  std::string MacroCodeBlock = ExpandedText->str();
+
+  std::vector<clang::tooling::Range> Ranges;
+  Ranges.emplace_back(0, MacroCodeBlock.length());
+
+  clang::tooling::Replacements Replacements = clang::format::reformat(
+      Style, MacroCodeBlock, Ranges, "<macro-expansion>");
+
+  llvm::Expected<std::string> Result =
+      clang::tooling::applyAllReplacements(MacroCodeBlock, Replacements);
+
+  It->getSecond() = Result ? std::move(*Result) : std::move(MacroCodeBlock);
+
+  return StringRef(It->getSecond());
+}
+
 void MacroExpansionContext::dumpExpansionRanges() const {
   dumpExpansionRangesToStream(llvm::dbgs());
 }

clang/lib/StaticAnalyzer/Core/PlistDiagnostics.cpp

@@ -835,7 +835,7 @@ getExpandedMacro(SourceLocation MacroExpansionLoc,
                  const SourceManager &SM) {
   if (auto CTUMacroExpCtx =
           CTU.getMacroExpansionContextForSourceLocation(MacroExpansionLoc)) {
-    return CTUMacroExpCtx->getExpandedText(MacroExpansionLoc);
+    return CTUMacroExpCtx->getFormattedExpandedText(MacroExpansionLoc);
   }
-  return MacroExpansions.getExpandedText(MacroExpansionLoc);
+  return MacroExpansions.getFormattedExpandedText(MacroExpansionLoc);
 }

clang/test/Analysis/plist-macros-with-expansion-ctu.c

@@ -66,7 +66,7 @@ void test3(void) {
 // CHECK-NEXT:    <key>file</key><integer>0</integer>
 // CHECK-NEXT:   </dict>
 // CHECK-NEXT:   <key>name</key><string>M</string>
-// CHECK-NEXT:   <key>expansion</key><string>F1 (&amp;X )</string>
+// CHECK-NEXT:   <key>expansion</key><string>F1
 // CHECK-NEXT:  </dict>
 // CHECK-NEXT: </array>
 
@@ -89,7 +89,7 @@ void test4(void) {
 // CHECK-NEXT:    <key>file</key><integer>0</integer>
 // CHECK-NEXT:   </dict>
 // CHECK-NEXT:   <key>name</key><string>M</string>
-// CHECK-NEXT:   <key>expansion</key><string>F2 (&amp;X )</string>
+// CHECK-NEXT:   <key>expansion</key><string>F2
 // CHECK-NEXT:  </dict>
 // CHECK-NEXT: </array>
 

clang/test/Analysis/plist-macros-with-expansion.c

@@ -22,7 +22,7 @@ void test_strange_macro_expansion(void) {
 // CHECK-NEXT:    <key>file</key><integer>0</integer>
 // CHECK-NEXT:   </dict>
 // CHECK-NEXT:   <key>name</key><string>STRANGE_FN(path)</string>
-// CHECK-NEXT:   <key>expansion</key><string>STRANGE_FN (path ,0)</string>
+// CHECK-NEXT:   <key>expansion</key><string>STRANGE_FN
 // CHECK-NEXT:  </dict>
 // CHECK-NEXT: </array>