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[dfsan] Record dfsan metadata in globals 

This will allow identifying exactly how many shadow bytes were used
during compilation, for when fast8 mode is introduced.

Also, it will provide a consistent matching point for instrumentation
tests so that the exact llvm type used (i8 or i16) for the shadow can
be replaced by a pattern substitution. This is handy for tests with
multiple prefixes.

Reviewed by: stephan.yichao.zhao, morehouse

Differential Revision: https://reviews.llvm.org/D97409
This commit is contained in:
George Balatsouras 2021-02-24 11:42:30 -08:00
parent 812a906133
commit c9075a1c8e
2 changed files with 35 additions and 10 deletions
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23
llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
View File

@ -450,6 +450,7 @@ class DataFlowSanitizer {
Constant *getOrBuildTrampolineFunction(FunctionType *FT, StringRef FName);
void initializeCallbackFunctions(Module &M);
void initializeRuntimeFunctions(Module &M);
void injectMetadataGlobals(Module &M);
bool init(Module &M);
@ -1267,6 +1268,26 @@ void DataFlowSanitizer::initializeCallbackFunctions(Module &M) {
Mod->getOrInsertFunction("__dfsan_cmp_callback", DFSanCmpCallbackFnTy);
}
void DataFlowSanitizer::injectMetadataGlobals(Module &M) {
// These variables can be used:
// - by the runtime (to discover what the shadow width was, during
// compilation)
// - in testing (to avoid hardcoding the shadow width and type but instead
// extract them by pattern matching)
Type *IntTy = Type::getInt32Ty(*Ctx);
(void)Mod->getOrInsertGlobal("__dfsan_shadow_width_bits", IntTy, [&] {
return new GlobalVariable(
M, IntTy, /*isConstant=*/true, GlobalValue::WeakODRLinkage,
ConstantInt::get(IntTy, ShadowWidthBits), "__dfsan_shadow_width_bits");
});
(void)Mod->getOrInsertGlobal("__dfsan_shadow_width_bytes", IntTy, [&] {
return new GlobalVariable(M, IntTy, /*isConstant=*/true,
GlobalValue::WeakODRLinkage,
ConstantInt::get(IntTy, ShadowWidthBytes),
"__dfsan_shadow_width_bytes");
});
}
bool DataFlowSanitizer::runImpl(Module &M) {
init(M);
@ -1307,6 +1328,8 @@ bool DataFlowSanitizer::runImpl(Module &M) {
"__dfsan_track_origins");
});
injectMetadataGlobals(M);
ExternalShadowMask =
Mod->getOrInsertGlobal(kDFSanExternShadowPtrMask, IntptrTy);

22
llvm/test/Instrumentation/DataFlowSanitizer/basic.ll
View File

@ -9,34 +9,36 @@ target triple = "x86_64-unknown-linux-gnu"
; CHECK: @__dfsan_retval_origin_tls = external thread_local(initialexec) global i32
; CHECK_NO_ORIGIN: @__dfsan_track_origins = weak_odr constant i32 0
; CHECK_ORIGIN: @__dfsan_track_origins = weak_odr constant i32 1
; CHECK: @__dfsan_shadow_width_bits = weak_odr constant i32 [[#SBITS:]]
; CHECK: @__dfsan_shadow_width_bytes = weak_odr constant i32 [[#SBYTES:]]
; CHECK: @__dfsan_shadow_ptr_mask = external global i64
; CHECK: declare void @__dfsan_load_callback(i16, i8*)
; CHECK: declare void @__dfsan_store_callback(i16, i8*)
; CHECK: declare void @__dfsan_mem_transfer_callback(i16*, i64)
; CHECK: declare void @__dfsan_cmp_callback(i16)
; CHECK: declare void @__dfsan_load_callback(i[[#SBITS]], i8*)
; CHECK: declare void @__dfsan_store_callback(i[[#SBITS]], i8*)
; CHECK: declare void @__dfsan_mem_transfer_callback(i[[#SBITS]]*, i64)
; CHECK: declare void @__dfsan_cmp_callback(i[[#SBITS]])
; CHECK: ; Function Attrs: nounwind readnone
; CHECK-NEXT: declare zeroext i16 @__dfsan_union(i16 zeroext, i16 zeroext) #0
; CHECK-NEXT: declare zeroext i[[#SBITS]] @__dfsan_union(i[[#SBITS]] zeroext, i[[#SBITS]] zeroext) #0
; CHECK: ; Function Attrs: nounwind readnone
; CHECK-NEXT: declare zeroext i16 @dfsan_union(i16 zeroext, i16 zeroext) #0
; CHECK-NEXT: declare zeroext i[[#SBITS]] @dfsan_union(i[[#SBITS]] zeroext, i[[#SBITS]] zeroext) #0
; CHECK: ; Function Attrs: nounwind readonly
; CHECK-NEXT: declare zeroext i16 @__dfsan_union_load(i16*, i64) #1
; CHECK-NEXT: declare zeroext i[[#SBITS]] @__dfsan_union_load(i[[#SBITS]]*, i64) #1
; CHECK: ; Function Attrs: nounwind readonly
; CHECK-NEXT: declare zeroext i16 @__dfsan_union_load_fast16labels(i16*, i64) #1
; CHECK-NEXT: declare zeroext i[[#SBITS]] @__dfsan_union_load_fast16labels(i[[#SBITS]]*, i64) #1
; CHECK: ; Function Attrs: nounwind readonly
; CHECK-NEXT: declare zeroext i64 @__dfsan_load_label_and_origin(i8*, i64) #1
; CHECK: declare void @__dfsan_unimplemented(i8*)
; CHECK: declare void @__dfsan_set_label(i16 zeroext, i32 zeroext, i8*, i64)
; CHECK: declare void @__dfsan_set_label(i[[#SBITS]] zeroext, i32 zeroext, i8*, i64)
; CHECK: declare void @__dfsan_nonzero_label()
; CHECK: declare void @__dfsan_vararg_wrapper(i8*)
; CHECK: declare zeroext i32 @__dfsan_chain_origin(i32 zeroext)
; CHECK: declare void @__dfsan_mem_origin_transfer(i8*, i8*, i64)
; CHECK: declare void @__dfsan_maybe_store_origin(i16 zeroext, i8*, i64, i32 zeroext)
; CHECK: declare void @__dfsan_maybe_store_origin(i[[#SBITS]] zeroext, i8*, i64, i32 zeroext)
define void @foo() {
ret void