jhenderson created this revision.
Herald added a subscriber: fhahn.
Depends on https://reviews.llvm.org/D29023, which is currently under review. In
that change, I am adding diagnostic information to LLVM for why Stack Smash
Protection has been applied to each function. This is the second stage, namely
adding a new remark to clang, which is emitted when enabled via "-Rssp-reason".
https://reviews.llvm.org/D29027
Files:
include/clang/Basic/DiagnosticFrontendKinds.td
include/clang/Basic/DiagnosticGroups.td
lib/CodeGen/CodeGenAction.cpp
test/CodeGen/stack-protector-remarks.c
Index: test/CodeGen/stack-protector-remarks.c
===================================================================
--- test/CodeGen/stack-protector-remarks.c
+++ test/CodeGen/stack-protector-remarks.c
@@ -0,0 +1,60 @@
+// RUN: %clang_cc1 -emit-obj %s -Rssp-reason -stack-protector 2 -o /dev/null 2>&1 | FileCheck %s -check-prefix=CHECK1
+// CHECK1-NOT: no_ssp
+// CHECK1: call to alloca
+// CHECK1-NEXT: alloca_ssp()
+// CHECK1: stack allocated buffer or struct
+// CHECK1-NEXT: buffer_ssp()
+// CHECK1: stack allocated buffer or struct
+// CHECK1-NEXT: struct_ssp()
+// CHECK1: address of a local variable
+// CHECK1-NEXT: address_ssp()
+// CHECK1: stack allocated buffer or struct
+// CHECK1-NEXT: multiple_ssp
+// CHECK1: stack allocated buffer or struct
+// CHECK1: address of a local variable
+// CHECK1: call to alloca
+
+// RUN: %clang_cc1 -emit-obj %s -Rssp-reason -stack-protector 3 -o /dev/null 2>&1 | FileCheck %s -check-prefix=CHECK2
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: no_ssp
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: alloca_ssp()
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: buffer_ssp()
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: struct_ssp()
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: address_ssp()
+// CHECK2: function attribute or use of -fstack-protector-all
+// CHECK2-NEXT: multiple_ssp
+
+void no_ssp() {
+}
+
+void alloca_ssp() {
+ __builtin_alloca(2);
+}
+
+void buffer_ssp() {
+ int x[64];
+}
+
+struct X {
+ int x[64];
+};
+void struct_ssp() {
+ struct X x;
+}
+
+void address_ssp() {
+ int x = 32;
+ int * y = &x;
+}
+
+void multiple_ssp() {
+ struct X x;
+ int y[64];
+ __builtin_alloca(2);
+ int a = 32;
+ int * b = &a;
+}
Index: lib/CodeGen/CodeGenAction.cpp
===================================================================
--- lib/CodeGen/CodeGenAction.cpp
+++ lib/CodeGen/CodeGenAction.cpp
@@ -307,6 +307,9 @@
const llvm::OptimizationRemarkAnalysisAliasing &D);
void OptimizationFailureHandler(
const llvm::DiagnosticInfoOptimizationFailure &D);
+
+ /// \brief Specialized handler for Stack Protector remark diagnostics.
+ void SSPRemarkHandler(const DiagnosticInfoSSP &D);
};
void BackendConsumer::anchor() {}
@@ -631,6 +634,15 @@
EmitOptimizationMessage(D, diag::warn_fe_backend_optimization_failure);
}
+void BackendConsumer::SSPRemarkHandler(const DiagnosticInfoSSP &D) {
+ StringRef Filename;
+ unsigned Line, Column;
+ bool BadDebugInfo = false;
+ FullSourceLoc Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename,
+ Line, Column);
+ Diags.Report(Loc, diag::remark_ssp_applied_reason) << D.Reason();
+}
+
/// \brief This function is invoked when the backend needs
/// to report something to the user.
void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
@@ -688,6 +700,9 @@
case llvm::DK_Unsupported:
UnsupportedDiagHandler(cast<DiagnosticInfoUnsupported>(DI));
return;
+ case llvm::DK_SSPReason:
+ SSPRemarkHandler(cast<DiagnosticInfoSSP>(DI));
+ return;
default:
// Plugin IDs are not bound to any value as they are set dynamically.
ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -905,3 +905,7 @@
// A warning group for warnings about code that clang accepts when
// compiling OpenCL C/C++ but which is not compatible with the SPIR spec.
def SpirCompat : DiagGroup<"spir-compat">;
+
+// A remark group for remarks about why stack protection was applied to a
+// function.
+def SSPReason : DiagGroup<"ssp-reason">;
Index: include/clang/Basic/DiagnosticFrontendKinds.td
===================================================================
--- include/clang/Basic/DiagnosticFrontendKinds.td
+++ include/clang/Basic/DiagnosticFrontendKinds.td
@@ -224,4 +224,11 @@
def warn_option_invalid_ocl_version : Warning<
"OpenCL version %0 does not support the option '%1'">, InGroup<Deprecated>;
+
+def remark_ssp_applied_reason
+ : Remark<"SSP applied to function due to %select{an unknown reason|a "
+ "call to alloca|a stack allocated buffer or struct containing a "
+ "buffer|the address of a local variable being taken|a function "
+ "attribute or use of -fstack-protector-all}0">,
+ InGroup<SSPReason>;
}
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