Now that macro expansion notes are real notes and go through the same

formatting as any other diagnostic, they will be properly line wrapped and
otherwise pretty printed. Let's take advantage of that and the new factoring to
add some helpful information to them (much like template backtrace notes and
other notes): the name of the macro whose expansion is being noted. This makes
a world of difference if caret diagnostics are disabled, making the expansion
notes actually useful in this case. It also helps ensure that in edge cases the
information the user needs is present. Consider:

% nl -ba t5.cc
     1  #define M(x, y, z) \
     2    y
     3
     4  M(
     5    1,
     6    2,
     7    3);

We now produce:
% ./bin/clang -fsyntax-only t5.cc
t5.cc:6:3: error: expected unqualified-id
  2,
  ^
t5.cc:2:3: note: expanded from macro: M
  y
  ^
1 error generated.

Without the added information in the note, the name of the macro being expanded
would never be shown.

This also deletes a FIXME to use the diagnostic formatting. It's not yet clear
to me that we *can* do this reasonably, and the production of this message was
my primary goal here anyways.

I'd love any comments or suggestions on improving these notes, their wording,
etc. Currently, I need to make them provide more helpful information in the
presence of a token-pasting buffer, and I'm pondering adding something along
the lines of "expanded from argument N of macro: ...".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142127 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Frontend/TextDiagnostic.cpp b/lib/Frontend/TextDiagnostic.cpp
index 7b3ebc4cd645f7bed465980b91fcb1575de45df1..8dab0afcac3c7dc2eb943b1a5811c3907d4ed719 100644 (file)
--- a/lib/Frontend/TextDiagnostic.cpp
+++ b/lib/Frontend/TextDiagnostic.cpp
@@ -689,6 +689,9 @@ void TextDiagnostic::emitMacroExpansionsAndCarets(
   emitMacroExpansionsAndCarets(OneLevelUp, Level, Ranges, Hints, MacroDepth,
                                OnMacroInst + 1);
 
+  // Save the original location so we can find the spelling of the macro call.
+  SourceLocation MacroLoc = Loc;
+
   // Map the location.
   Loc = getImmediateMacroCalleeLoc(SM, Loc);
 
@@ -726,9 +729,27 @@ void TextDiagnostic::emitMacroExpansionsAndCarets(
     return;
   }
 
-  // FIXME: Format an actual diagnostic rather than a hard coded string.
+  // Walk past macro argument expanions.
+  while (SM.isMacroArgExpansion(MacroLoc))
+    MacroLoc = SM.getImmediateExpansionRange(MacroLoc).first;
+
+  // Find the spelling location of the start of the non-argument expansion
+  // range. This is where the macro name was spelled in order to begin
+  // expanding this macro.
+  MacroLoc = SM.getSpellingLoc(SM.getImmediateExpansionRange(MacroLoc).first);
+
+  // Dig out the buffer where the macro name was spelled and the extents of the
+  // name so that we can render it into the expansion note.
+  std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(MacroLoc);
+  unsigned MacroTokenLength = Lexer::MeasureTokenLength(MacroLoc, SM, LangOpts);
+  StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
+
+  llvm::SmallString<100> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  Message << "expanded from macro: "
+          << ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
   emitDiagnostic(SM.getSpellingLoc(Loc), DiagnosticsEngine::Note,
-                 "expanded from:",
+                 Message.str(),
                  Ranges, ArrayRef<FixItHint>());
 }
 

diff --git a/test/Misc/caret-diags-macros.c b/test/Misc/caret-diags-macros.c
index 3d2e576d64144f1baf96e92f020fa727d37f58a1..38a1e9946b07c400339586c61d778b98127be7ee 100644 (file)
--- a/test/Misc/caret-diags-macros.c
+++ b/test/Misc/caret-diags-macros.c
@@ -6,8 +6,8 @@ void foo() {
   M1(
     M2);
   // CHECK: :7:{{[0-9]+}}: warning: expression result unused
-  // CHECK: :4:{{[0-9]+}}: note: expanded from:
-  // CHECK: :3:{{[0-9]+}}: note: expanded from:
+  // CHECK: :4:{{[0-9]+}}: note: expanded from macro: M2
+  // CHECK: :3:{{[0-9]+}}: note: expanded from macro: M1
 }
 
 #define A 1
@@ -16,9 +16,9 @@ void foo() {
 void bar() {
   C;
   // CHECK: :17:3: warning: expression result unused
-  // CHECK: :15:11: note: expanded from:
-  // CHECK: :14:11: note: expanded from:
-  // CHECK: :13:11: note: expanded from:
+  // CHECK: :15:11: note: expanded from macro: C
+  // CHECK: :14:11: note: expanded from macro: B
+  // CHECK: :13:11: note: expanded from macro: A
 }
 
 // rdar://7597492
@@ -46,28 +46,28 @@ void test() {
   // its easy to FileCheck.
   // CHECK-NEXT: macro_args3(1);
   // CHECK-NEXT: ~~~~~~~~~~~~^~
-  // CHECK: {{.*}}:36:36: note: expanded from:
-  // CHECK: {{.*}}:35:36: note: expanded from:
-  // CHECK: {{.*}}:34:24: note: expanded from:
+  // CHECK: {{.*}}:36:36: note: expanded from macro: macro_args3
+  // CHECK: {{.*}}:35:36: note: expanded from macro: macro_args2
+  // CHECK: {{.*}}:34:24: note: expanded from macro: macro_args1
 
   macro_many_args3(
     1,
     2,
     3);
   // CHECK: {{.*}}:55:5: warning: expression result unused
-  // CHECK: {{.*}}:40:55: note: expanded from:
-  // CHECK: {{.*}}:39:55: note: expanded from:
-  // CHECK: {{.*}}:38:35: note: expanded from:
+  // CHECK: {{.*}}:40:55: note: expanded from macro: macro_many_args3
+  // CHECK: {{.*}}:39:55: note: expanded from macro: macro_many_args2
+  // CHECK: {{.*}}:38:35: note: expanded from macro: macro_many_args1
 
   macro_many_args3(
     1,
     M2,
     3);
   // CHECK: {{.*}}:64:5: warning: expression result unused
-  // CHECK: {{.*}}:4:12: note: expanded from:
-  // CHECK: {{.*}}:40:55: note: expanded from:
-  // CHECK: {{.*}}:39:55: note: expanded from:
-  // CHECK: {{.*}}:38:35: note: expanded from:
+  // CHECK: {{.*}}:4:12: note: expanded from macro: M2
+  // CHECK: {{.*}}:40:55: note: expanded from macro: macro_many_args3
+  // CHECK: {{.*}}:39:55: note: expanded from macro: macro_many_args2
+  // CHECK: {{.*}}:38:35: note: expanded from macro: macro_many_args1
 
   macro_many_args3(
     1,
@@ -78,11 +78,11 @@ void test() {
   // arguments.
   // CHECK-NEXT: macro_args2(2),
   // CHECK-NEXT: ~~~~~~~~~~~~^~~
-  // CHECK: {{.*}}:35:36: note: expanded from:
-  // CHECK: {{.*}}:34:24: note: expanded from:
-  // CHECK: {{.*}}:40:55: note: expanded from:
-  // CHECK: {{.*}}:39:55: note: expanded from:
-  // CHECK: {{.*}}:38:35: note: expanded from:
+  // CHECK: {{.*}}:35:36: note: expanded from macro: macro_args2
+  // CHECK: {{.*}}:34:24: note: expanded from macro: macro_args1
+  // CHECK: {{.*}}:40:55: note: expanded from macro: macro_many_args3
+  // CHECK: {{.*}}:39:55: note: expanded from macro: macro_many_args2
+  // CHECK: {{.*}}:38:35: note: expanded from macro: macro_many_args1
 }
 
 #define variadic_args1(x, y, ...) y
@@ -94,9 +94,9 @@ void test2() {
   // CHECK: {{.*}}:93:21: warning: expression result unused
   // CHECK-NEXT: variadic_args3(1, 2, 3, 4);
   // CHECK-NEXT: ~~~~~~~~~~~~~~~~~~^~~~~~~~
-  // CHECK: {{.*}}:90:53: note: expanded from:
-  // CHECK: {{.*}}:89:50: note: expanded from:
-  // CHECK: {{.*}}:88:35: note: expanded from:
+  // CHECK: {{.*}}:90:53: note: expanded from macro: variadic_args3
+  // CHECK: {{.*}}:89:50: note: expanded from macro: variadic_args2
+  // CHECK: {{.*}}:88:35: note: expanded from macro: variadic_args1
 }
 
 #define variadic_pasting_args1(x, y, z) y
@@ -108,13 +108,13 @@ void test2() {
 void test3() {
   variadic_pasting_args3(1, 2, 3, 4);
   // CHECK: {{.*}}:109:32: warning: expression result unused
-  // CHECK: {{.*}}:105:72: note: expanded from:
-  // CHECK: {{.*}}:103:68: note: expanded from:
-  // CHECK: {{.*}}:102:41: note: expanded from:
+  // CHECK: {{.*}}:105:72: note: expanded from macro: variadic_pasting_args3
+  // CHECK: {{.*}}:103:68: note: expanded from macro: variadic_pasting_args2
+  // CHECK: {{.*}}:102:41: note: expanded from macro: variadic_pasting_args1
 
   variadic_pasting_args3a(1, 2, 3, 4);
   // CHECK: {{.*}}:115:30: warning: expression result unused
-  // CHECK: {{.*}}:106:71: note: expanded from:
-  // CHECK: {{.*}}:104:70: note: expanded from:
-  // CHECK: {{.*}}:102:41: note: expanded from:
+  // CHECK: {{.*}}:106:71: note: expanded from macro: variadic_pasting_args3a
+  // CHECK: {{.*}}:104:70: note: expanded from macro: variadic_pasting_args2a
+  // CHECK: {{.*}}:102:41: note: expanded from macro: variadic_pasting_args1
 }

diff --git a/test/Misc/include-stack-for-note-flag.cpp b/test/Misc/include-stack-for-note-flag.cpp
index cfec5066a05f7c4afb91703dc99e4cb0a07d97bf..7058cb0774f9f5bb74730acb6d2f935f7adba066 100644 (file)
--- a/test/Misc/include-stack-for-note-flag.cpp
+++ b/test/Misc/include-stack-for-note-flag.cpp
@@ -18,11 +18,11 @@ bool macro(int x, int y) {
 // STACK: note: candidate function not viable
 // STACK: error: comparison between pointer and integer
 // STACK:  In file included from
-// STACK: note: expanded from:
+// STACK: note: expanded from macro:
 
 // STACKLESS: error: no matching function for call to 'foo'
 // STACKLESS-NOT:  In file included from
 // STACKLESS: note: candidate function not viable
 // STACKLESS: error: comparison between pointer and integer
 // STACKLESS-NOT:  In file included from
-// STACKLESS: note: expanded from:
+// STACKLESS: note: expanded from macro:

diff --git a/test/Misc/macro-backtrace.c b/test/Misc/macro-backtrace.c
index a76d4d22e381da72396d53acad418fb3fd8f0fac..f292519e33eccec9ff7cbcb329d7897e942453cb 100644 (file)
--- a/test/Misc/macro-backtrace.c
+++ b/test/Misc/macro-backtrace.c
@@ -20,16 +20,16 @@ void f(int *ip, float *fp) {
   // RUN:   | FileCheck %s -check-prefix=CHECK-LIMIT
   // CHECK-LIMIT: macro-backtrace.c:18:7: warning: comparison of distinct pointer types ('int *' and 'float *')
   // CHECK-LIMIT: if (M12(ip, fp)) { }
-  // CHECK-LIMIT: macro-backtrace.c:15:19: note: expanded from:
+  // CHECK-LIMIT: macro-backtrace.c:15:19: note: expanded from macro: M12
   // CHECK-LIMIT: #define M12(A, B) M11(A, B)
-  // CHECK-LIMIT: macro-backtrace.c:14:19: note: expanded from:
+  // CHECK-LIMIT: macro-backtrace.c:14:19: note: expanded from macro: M11
   // CHECK-LIMIT: #define M11(A, B) M10(A, B)
   // CHECK-LIMIT: note: (skipping 7 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
-  // CHECK-LIMIT: macro-backtrace.c:6:18: note: expanded from:
+  // CHECK-LIMIT: macro-backtrace.c:6:18: note: expanded from macro: M3
   // CHECK-LIMIT: #define M3(A, B) M2(A, B)
-  // CHECK-LIMIT: macro-backtrace.c:5:18: note: expanded from:
+  // CHECK-LIMIT: macro-backtrace.c:5:18: note: expanded from macro: M2
   // CHECK-LIMIT: #define M2(A, B) M1(A, B)
-  // CHECK-LIMIT: macro-backtrace.c:4:23: note: expanded from:
+  // CHECK-LIMIT: macro-backtrace.c:4:23: note: expanded from macro: M1
   // CHECK-LIMIT: #define M1(A, B) ((A) < (B))
 
   // FIXME: We should have higher quality messages, especially when caret
@@ -37,11 +37,11 @@ void f(int *ip, float *fp) {
   // RUN: %clang_cc1 -fsyntax-only -fno-caret-diagnostics %s 2>&1 \
   // RUN:   | FileCheck %s -check-prefix=CHECK-NO-CARETS
   // CHECK-NO-CARETS: macro-backtrace.c:18:7: warning: comparison of distinct pointer types ('int *' and 'float *')
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:15:19: note: expanded from:
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:14:19: note: expanded from:
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:13:19: note: expanded from:
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:15:19: note: expanded from macro: M12
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:14:19: note: expanded from macro: M11
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:13:19: note: expanded from macro: M10
   // CHECK-NO-CARETS-NEXT: note: (skipping 6 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:6:18: note: expanded from:
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:5:18: note: expanded from:
-  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:4:23: note: expanded from:
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:6:18: note: expanded from macro: M3
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:5:18: note: expanded from macro: M2
+  // CHECK-NO-CARETS-NEXT: macro-backtrace.c:4:23: note: expanded from macro: M1
 }