Stop printing macro backtraces that don't help diagnostics.

When displaying the macro backtrace, ignore some of the backtraces that do not
provide extra information to the diagnostic.  Typically, if the problem is
entirely contained within a macro argument, the macro expansion is often not
needed.  Also take into account SourceRange's attached to the diagnostic when
selecting which backtraces to ignore.  Two previous test cases have also been
updated.

Patch by Zhengkai Wu, with minor formatting fixes.

Differential Revision: http://reviews.llvm.org/D11778

llvm-svn: 244788

diff --git a/clang/lib/Frontend/DiagnosticRenderer.cpp b/clang/lib/Frontend/DiagnosticRenderer.cpp
index 46bef19..393d379 100644 (file)
--- a/clang/lib/Frontend/DiagnosticRenderer.cpp
+++ b/clang/lib/Frontend/DiagnosticRenderer.cpp
@@ -423,6 +423,38 @@ void DiagnosticRenderer::emitSingleMacroExpansion(
                  SpellingRanges, None, &SM);
 }
 
+static bool checkRangeForMacroArgExpansion(CharSourceRange Range,
+                                           const SourceManager &SM) {
+  SourceLocation BegLoc = Range.getBegin(), EndLoc = Range.getEnd();
+  while (BegLoc != EndLoc) {
+    if (!SM.isMacroArgExpansion(BegLoc))
+      return false;
+    BegLoc.getLocWithOffset(1);
+  }
+
+  return SM.isMacroArgExpansion(BegLoc);
+}
+
+/// A helper function to check if the current ranges are all inside
+/// the macro expansions.
+static bool checkRangesForMacroArgExpansion(SourceLocation Loc,
+                                            ArrayRef<CharSourceRange> Ranges,
+                                            const SourceManager &SM) {
+  assert(Loc.isMacroID() && "Must be a macro expansion!");
+
+  SmallVector<CharSourceRange, 4> SpellingRanges;
+  mapDiagnosticRanges(Loc, Ranges, SpellingRanges, &SM);
+
+  if (!SM.isMacroArgExpansion(Loc))
+    return false;
+
+  for (auto I = SpellingRanges.begin(), E = SpellingRanges.end(); I != E; ++I)
+    if (!checkRangeForMacroArgExpansion(*I, SM))
+      return false;
+
+  return true;
+}
+
 /// \brief Recursively emit notes for each macro expansion and caret
 /// diagnostics where appropriate.
 ///
@@ -443,12 +475,19 @@ void DiagnosticRenderer::emitMacroExpansions(SourceLocation Loc,
 
   // Produce a stack of macro backtraces.
   SmallVector<SourceLocation, 8> LocationStack;
+  unsigned IgnoredEnd = 0;
   while (Loc.isMacroID()) {
     LocationStack.push_back(Loc);
+    if (checkRangesForMacroArgExpansion(Loc, Ranges, SM))
+      IgnoredEnd = LocationStack.size();
+
     Loc = SM.getImmediateMacroCallerLoc(Loc);
     assert(!Loc.isInvalid() && "must have a valid source location here");
   }
 
+  LocationStack.erase(LocationStack.begin(),
+                      LocationStack.begin() + IgnoredEnd);
+
   unsigned MacroDepth = LocationStack.size();
   unsigned MacroLimit = DiagOpts->MacroBacktraceLimit;
   if (MacroDepth <= MacroLimit || MacroLimit == 0) {

diff --git a/clang/test/Misc/diag-presumed.c b/clang/test/Misc/diag-presumed.c
index 70f2f24..2f05069 100644 (file)
--- a/clang/test/Misc/diag-presumed.c
+++ b/clang/test/Misc/diag-presumed.c
@@ -6,13 +6,11 @@
 X(int n = error);
 
 // PRESUMED: diag-presumed.c:101:11: error: use of undeclared identifier 'error'
-// PRESUMED: diag-presumed.c:100:14: note: expanded from
 // SPELLING: diag-presumed.c:6:11: error: use of undeclared identifier 'error'
-// SPELLING: diag-presumed.c:5:14: note: expanded from
 
 ;
-// PRESUMED: diag-presumed.c:108:1: error: extra ';' outside of a functio
-// SPELLING: diag-presumed.c:13:1: error: extra ';' outside of a functio
+// PRESUMED: diag-presumed.c:106:1: error: extra ';' outside of a functio
+// SPELLING: diag-presumed.c:11:1: error: extra ';' outside of a functio
 
 # 1 "thing1.cc" 1
 # 1 "thing1.h" 1
@@ -24,13 +22,13 @@ X(int n = error);
 // SPELLING-NOT: extra ';'
 
 another error;
-// PRESUMED: included from {{.*}}diag-presumed.c:112:
+// PRESUMED: included from {{.*}}diag-presumed.c:110:
 // PRESUMED: from thing1.cc:1:
 // PRESUMED: from thing1.h:1:
 // PRESUMED: systemheader.h:7:1: error: unknown type name 'another'
 
 // SPELLING-NOT: included from
-// SPELLING: diag-presumed.c:26:1: error: unknown type name 'another'
+// SPELLING: diag-presumed.c:24:1: error: unknown type name 'another'
 
 # 1 "thing1.h" 2
 # 1 "thing1.cc" 2

diff --git a/clang/test/Misc/reduced-diags-macros-backtrace.cpp b/clang/test/Misc/reduced-diags-macros-backtrace.cpp
new file mode 100644 (file)
index 0000000..70c4122
--- /dev/null
+++ b/clang/test/Misc/reduced-diags-macros-backtrace.cpp
@@ -0,0 +1,47 @@
+// RUN: not %clang_cc1 -fsyntax-only -fmacro-backtrace-limit 0 %s 2>&1 | FileCheck %s --check-prefix=ALL
+// RUN: not %clang_cc1 -fsyntax-only -fmacro-backtrace-limit 2 %s 2>&1 | FileCheck %s --check-prefix=SKIP
+
+#define F(x) x + 1
+#define G(x) F(x) + 2
+#define ADD(x,y) G(x) + y
+#define LEVEL4(x) ADD(p,x)
+#define LEVEL3(x) LEVEL4(x)
+#define LEVEL2(x) LEVEL3(x)
+#define LEVEL1(x) LEVEL2(x)
+
+int a = LEVEL1(b);
+
+// ALL: {{.*}}:12:9: error: use of undeclared identifier 'p'
+// ALL-NEXT: int a = LEVEL1(b);
+// ALL-NEXT:         ^
+// ALL-NEXT: {{.*}}:10:19: note: expanded from macro 'LEVEL1'
+// ALL-NEXT: #define LEVEL1(x) LEVEL2(x)
+// ALL-NEXT:                   ^
+// ALL-NEXT: {{.*}}:9:19: note: expanded from macro 'LEVEL2'
+// ALL-NEXT: #define LEVEL2(x) LEVEL3(x)
+// ALL-NEXT:                   ^
+// ALL-NEXT: {{.*}}:8:19: note: expanded from macro 'LEVEL3'
+// ALL-NEXT: #define LEVEL3(x) LEVEL4(x)
+// ALL-NEXT:                   ^
+// ALL-NEXT: {{.*}}:7:23: note: expanded from macro 'LEVEL4'
+// ALL-NEXT: #define LEVEL4(x) ADD(p,x)
+// ALL-NEXT:                       ^
+// ALL-NEXT: {{.*}}:12:16: error: use of undeclared identifier 'b'
+// ALL-NEXT: int a = LEVEL1(b);
+// ALL-NEXT:                ^
+// ALL-NEXT: 2 errors generated.
+
+// SKIP: {{.*}}:12:9: error: use of undeclared identifier 'p'
+// SKIP-NEXT: int a = LEVEL1(b);
+// SKIP-NEXT:         ^
+// SKIP-NEXT: {{.*}}:10:19: note: expanded from macro 'LEVEL1'
+// SKIP-NEXT: #define LEVEL1(x) LEVEL2(x)
+// SKIP-NEXT:                   ^
+// SKIP-NEXT: note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
+// SKIP-NEXT: {{.*}}:7:23: note: expanded from macro 'LEVEL4'
+// SKIP-NEXT: #define LEVEL4(x) ADD(p,x)
+// SKIP-NEXT:                       ^
+// SKIP-NEXT: {{.*}}:12:16: error: use of undeclared identifier 'b'
+// SKIP-NEXT: int a = LEVEL1(b);
+// SKIP-NEXT:                ^
+// SKIP-NEXT: 2 errors generated.

diff --git a/clang/test/Misc/reduced-diags-macros.cpp b/clang/test/Misc/reduced-diags-macros.cpp
new file mode 100644 (file)
index 0000000..d64c267
--- /dev/null
+++ b/clang/test/Misc/reduced-diags-macros.cpp
@@ -0,0 +1,29 @@
+// RUN: not %clang_cc1 -fsyntax-only %s 2>&1 | FileCheck %s -strict-whitespace
+
+#define NO_INITIATION(x) int a = x * 2
+#define NO_DEFINITION(x) int c = x * 2
+
+NO_INITIATION(a);
+NO_DEFINITION(b);
+
+// CHECK: {{.*}}:6:15: warning: variable 'a' is uninitialized when used within its own initialization
+// CHECK-NEXT: NO_INITIATION(a);
+// CHECK-NEXT: ~~~~~~~~~~~~~~^~
+// CHECK-NEXT: {{.*}}:3:34: note: expanded from macro 'NO_INITIATION'
+// CHECK-NEXT: #define NO_INITIATION(x) int a = x * 2
+// CHECK-NEXT:                                  ^
+
+// CHECK: {{.*}}:7:15: error: use of undeclared identifier 'b'
+// CHECK-NEXT: NO_DEFINITION(b);
+// CHECK-NEXT:               ^
+
+
+#define F(x) x + 1
+#define ADD(x,y) y + F(x)
+#define SWAP_ARGU(x,y) ADD(y,x)
+
+int  p = SWAP_ARGU(3, x);
+
+// CHECK: {{.*}}:25:23: error: use of undeclared identifier 'x'
+// CHECK-NEXT: int  p = SWAP_ARGU(3, x);
+// CHECK-NEXT:                       ^

diff --git a/clang/test/Preprocessor/macro_arg_slocentry_merge.c b/clang/test/Preprocessor/macro_arg_slocentry_merge.c
index 9ab385f..27a2a01 100644 (file)
--- a/clang/test/Preprocessor/macro_arg_slocentry_merge.c
+++ b/clang/test/Preprocessor/macro_arg_slocentry_merge.c
@@ -3,5 +3,3 @@
 #include "macro_arg_slocentry_merge.h"
 
 // CHECK: macro_arg_slocentry_merge.h:7:19: error: unknown type name 'win'
-// CHECK: macro_arg_slocentry_merge.h:5:16: note: expanded from macro 'WINDOW'
-// CHECK: macro_arg_slocentry_merge.h:6:18: note: expanded from macro 'P_'