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[Clang] Avoid crashing when generating crash diagnostics when '#pragma clang __debug [assert|crash|parser_crash|llvm_fatal_error|llvm_unreachable|overflow_stack]' are used
Previously, when the above '#pragma clang __debug' were used, Driver::generateCompilationDiagnostics() wouldn't work as expected. The 'clang -E' process created for diagnostics would crash, because it would reach again the intended crash in Pragma.cpp, PragmaDebugHandler::HandlePragma() while preprocessing. When generating crash diagnostics, we now disable the intended crashing behavior with a new cc1 flag -disable-pragma-debug-crash. Notes: - #pragma clang __debug llvm_report_fatal isn't currently tested by crash-report.c, because it needs exit() to be handled differently in -fintegrated-cc1 mode. See https://reviews.llvm.org/D73742 for an upcoming fix. - This is also needed to further validate that -MF is removed from the 'clang -E ' crash diagnostic cmd-line (currently not the case). See https://reviews.llvm.org/D74076 for an upcoming fix. Differential Revision: https://reviews.llvm.org/D74070
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‎clang/include/clang/Driver/CC1Options.td

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -866,6 +866,8 @@ def detailed_preprocessing_record : Flag<["-"], "detailed-preprocessing-record">
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HelpText<"include a detailed record of preprocessing actions">;
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def setup_static_analyzer : Flag<["-"], "setup-static-analyzer">,
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HelpText<"Set up preprocessor for static analyzer (done automatically when static analyzer is run).">;
869+
def disable_pragma_debug_crash : Flag<["-"], "disable-pragma-debug-crash">,
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HelpText<"Disable any #pragma clang __debug that can lead to crashing behavior. This is meant for testing.">;
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//===----------------------------------------------------------------------===//
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// OpenCL Options

‎clang/include/clang/Lex/PreprocessorOptions.h

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -189,6 +189,9 @@ class PreprocessorOptions {
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/// Set up preprocessor for RunAnalysis action.
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bool SetUpStaticAnalyzer = false;
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/// Prevents intended crashes when using #pragma clang __debug. For testing.
193+
bool DisablePragmaDebugCrash = false;
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public:
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PreprocessorOptions() : PrecompiledPreambleBytes(0, false) {}
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‎clang/lib/Driver/ToolChains/Clang.cpp

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4750,6 +4750,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
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: "-");
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}
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// Give the gen diagnostics more chances to succeed, by avoiding intentional
4754+
// crashes.
4755+
if (D.CCGenDiagnostics)
4756+
CmdArgs.push_back("-disable-pragma-debug-crash");
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47534758
bool UseSeparateSections = isUseSeparateSections(Triple);
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47554760
if (Args.hasFlag(options::OPT_ffunction_sections,

‎clang/lib/Frontend/CompilerInvocation.cpp

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3470,6 +3470,7 @@ static void ParsePreprocessorArgs(PreprocessorOptions &Opts, ArgList &Args,
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Opts.LexEditorPlaceholders = false;
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Opts.SetUpStaticAnalyzer = Args.hasArg(OPT_setup_static_analyzer);
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Opts.DisablePragmaDebugCrash = Args.hasArg(OPT_disable_pragma_debug_crash);
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}
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34753476
static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,

‎clang/lib/Lex/Pragma.cpp

Lines changed: 18 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -30,6 +30,7 @@
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#include "clang/Lex/PPCallbacks.h"
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#include "clang/Lex/Preprocessor.h"
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#include "clang/Lex/PreprocessorLexer.h"
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#include "clang/Lex/PreprocessorOptions.h"
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#include "clang/Lex/Token.h"
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#include "clang/Lex/TokenLexer.h"
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#include "llvm/ADT/ArrayRef.h"
@@ -1034,15 +1035,19 @@ struct PragmaDebugHandler : public PragmaHandler {
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IdentifierInfo *II = Tok.getIdentifierInfo();
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10361037
if (II->isStr("assert")) {
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llvm_unreachable("This is an assertion!");
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if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
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llvm_unreachable("This is an assertion!");
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} else if (II->isStr("crash")) {
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LLVM_BUILTIN_TRAP;
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if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
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LLVM_BUILTIN_TRAP;
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} else if (II->isStr("parser_crash")) {
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Token Crasher;
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Crasher.startToken();
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Crasher.setKind(tok::annot_pragma_parser_crash);
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Crasher.setAnnotationRange(SourceRange(Tok.getLocation()));
1045-
PP.EnterToken(Crasher, /*IsReinject*/false);
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if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash) {
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Token Crasher;
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Crasher.startToken();
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Crasher.setKind(tok::annot_pragma_parser_crash);
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Crasher.setAnnotationRange(SourceRange(Tok.getLocation()));
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PP.EnterToken(Crasher, /*IsReinject*/ false);
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}
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} else if (II->isStr("dump")) {
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Token Identifier;
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PP.LexUnexpandedToken(Identifier);
@@ -1074,9 +1079,11 @@ struct PragmaDebugHandler : public PragmaHandler {
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<< II->getName();
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}
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} else if (II->isStr("llvm_fatal_error")) {
1077-
llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");
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if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
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llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");
10781084
} else if (II->isStr("llvm_unreachable")) {
1079-
llvm_unreachable("#pragma clang __debug llvm_unreachable");
1085+
if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
1086+
llvm_unreachable("#pragma clang __debug llvm_unreachable");
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} else if (II->isStr("macro")) {
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Token MacroName;
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PP.LexUnexpandedToken(MacroName);
@@ -1103,7 +1110,8 @@ struct PragmaDebugHandler : public PragmaHandler {
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}
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M->dump();
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} else if (II->isStr("overflow_stack")) {
1106-
DebugOverflowStack();
1113+
if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
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DebugOverflowStack();
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} else if (II->isStr("captured")) {
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HandleCaptured(PP);
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} else {

‎clang/test/Driver/crash-report.c

Lines changed: 36 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,25 +1,56 @@
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// RUN: rm -rf %t
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// RUN: mkdir %t
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// RUN: env TMPDIR=%t TEMP=%t TMP=%t RC_DEBUG_OPTIONS=1 \
4-
// RUN: CC_PRINT_HEADERS=1 CC_LOG_DIAGNOSTICS=1 \
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// RUN: not %clang -fsyntax-only %s \
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// RUN: echo '-fsyntax-only \
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// RUN: -F/tmp/ -I /tmp/ -idirafter /tmp/ -iquote /tmp/ -isystem /tmp/ \
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// RUN: -iprefix /the/prefix -iwithprefix /tmp -iwithprefixbefore /tmp/ \
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// RUN: -Xclang -internal-isystem -Xclang /tmp/ \
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// RUN: -Xclang -internal-externc-isystem -Xclang /tmp/ \
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// RUN: -Xclang -main-file-name -Xclang foo.c \
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// RUN: -DFOO=BAR -DBAR="BAZ QUX" 2>&1 | FileCheck %s
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// RUN: -DFOO=BAR -DBAR="BAZ QUX"' > %t.rsp
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// RUN: env TMPDIR=%t TEMP=%t TMP=%t RC_DEBUG_OPTIONS=1 \
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// RUN: CC_PRINT_HEADERS=1 CC_LOG_DIAGNOSTICS=1 \
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// RUN: not %clang %s @%t.rsp -DPARSER 2>&1 | FileCheck %s
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// RUN: cat %t/crash-report-*.c | FileCheck --check-prefix=CHECKSRC %s
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// RUN: cat %t/crash-report-*.sh | FileCheck --check-prefix=CHECKSH %s
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// RUN: env TMPDIR=%t TEMP=%t TMP=%t RC_DEBUG_OPTIONS=1 \
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// RUN: CC_PRINT_HEADERS=1 CC_LOG_DIAGNOSTICS=1 \
20+
// RUN: not %clang %s @%t.rsp -DCRASH 2>&1 | FileCheck %s
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// RUN: cat %t/crash-report-*.c | FileCheck --check-prefix=CHECKSRC %s
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// RUN: cat %t/crash-report-*.sh | FileCheck --check-prefix=CHECKSH %s
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24+
// RUN: env TMPDIR=%t TEMP=%t TMP=%t RC_DEBUG_OPTIONS=1 \
25+
// RUN: CC_PRINT_HEADERS=1 CC_LOG_DIAGNOSTICS=1 \
26+
// RUN: not %clang %s @%t.rsp -DASSERT 2>&1 | FileCheck %s
27+
// RUN: cat %t/crash-report-*.c | FileCheck --check-prefix=CHECKSRC %s
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// RUN: cat %t/crash-report-*.sh | FileCheck --check-prefix=CHECKSH %s
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30+
// RUN: env TMPDIR=%t TEMP=%t TMP=%t RC_DEBUG_OPTIONS=1 \
31+
// RUN: CC_PRINT_HEADERS=1 CC_LOG_DIAGNOSTICS=1 \
32+
// RUN: not %clang %s @%t.rsp -DUNREACHABLE 2>&1 | FileCheck %s
33+
// RUN: cat %t/crash-report-*.c | FileCheck --check-prefix=CHECKSRC %s
34+
// RUN: cat %t/crash-report-*.sh | FileCheck --check-prefix=CHECKSH %s
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1436
// REQUIRES: crash-recovery
1537

38+
#ifdef PARSER
1639
#pragma clang __debug parser_crash
40+
#elif CRASH
41+
#pragma clang __debug crash
42+
#elif ASSERT
43+
#pragma clang __debug assert
44+
#elif UNREACHABLE
45+
#pragma clang __debug llvm_unreachable
46+
#endif
47+
1748
// CHECK: Preprocessed source(s) and associated run script(s) are located at:
1849
// CHECK-NEXT: note: diagnostic msg: {{.*}}crash-report-{{.*}}.c
1950
FOO
2051
// CHECKSRC: FOO
2152
// CHECKSH: # Crash reproducer
22-
// CHECKSH-NEXT: # Driver args: "-fsyntax-only"
53+
// CHECKSH-NEXT: # Driver args: {{.*}}"-fsyntax-only"
2354
// CHECKSH-SAME: "-D" "FOO=BAR"
2455
// CHECKSH-SAME: "-D" "BAR=BAZ QUX"
2556
// CHECKSH-NEXT: # Original command: {{.*$}}

‎clang/test/Driver/output-file-cleanup.c

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,7 @@
1+
2+
// Temporarily disable this test until the -MF flag is properly removed from the diagnostics generation.
3+
// XFAIL: *
4+
15
// RUN: rm -f "%t.d" "%t1.s" "%t2.s" "%t3.s" "%t4.s" "%t5.s"
26
//
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// RUN: touch %t.s

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