[ubsan] Disable the object-size check at -O0

[vsk]

Summary

This is motivated by the thread:
[cfe-dev] Disabling ubsan's object size check at -O0

I think the driver is the best place to disable a sanitizer check at particular optimization levels. Doing so in the frontend is messy, and makes it really hard to test IR generation for the check. Making the change in CodeGen has the same issues.

[vsk]

Add a diagnostic for users who explicitly turn the object-size check on at -O0, and tighten up the test a bit.

lib/Driver/SanitizerArgs.cpp

SanitizerArgs::SanitizerArgs(const ToolChain &TC,
   SanitizerMask Kinds = 0;
   const SanitizerMask Supported = setGroupBits(TC.getSupportedSanitizers());
   ToolChain::RTTIMode RTTIMode = TC.getRTTIMode();
 
   const Driver &D = TC.getDriver();
   SanitizerMask TrappingKinds = parseSanitizeTrapArgs(D, Args);
   SanitizerMask InvalidTrappingKinds = TrappingKinds & NotAllowedWithTrap;
 
+  // The object-size sanitizer should not be enabled at -O0.
+  Arg *OptLevel = Args.getLastArg(options::OPT_O_Group);
+  if (!OptLevel || OptLevel->getOption().matches(options::OPT_O0))
+    AllRemove |= SanitizerKind::ObjectSize;
+
   for (ArgList::const_reverse_iterator I = Args.rbegin(), E = Args.rend();
        I != E; ++I) {
     const auto *Arg = *I;
     if (Arg->getOption().matches(options::OPT_fsanitize_EQ)) {
       Arg->claim();
       SanitizerMask Add = parseArgValues(D, Arg, true);
       AllAddedKinds |= expandSanitizerGroups(Add);
 

test/Driver/fsanitize-object-size.c

+// Check that the object size check is disabled at -O0.
+//
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size %s -O0 -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=null,object-size %s -### 2>&1 | FileCheck %s --check-prefixes=CHECK-NO-OSIZE
+
+// Check that the object size check is enabled at other optimization levels.
+//
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -O1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -O2 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -O3 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -O4 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -Ofast %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -Os %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -Oz %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=object-size -Og %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+
+// Use of trap mode shouldn't affect the object size check.
+//
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined -O1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined-trap -O1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined-trap -fsanitize-undefined-trap-on-error -O1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-HAS-OSIZE
+
+// CHECK-HAS-OSIZE: -fsanitize={{[^ ]*}}object-size
+// CHECK-NO-OSIZE-NOT: -fsanitize={{[^ ]*}}object-size

test/Driver/fsanitize.c

 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined -fno-sanitize-trap=signed-integer-overflow %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP2
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined-trap -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
 // RUN: %clang -target x86_64-linux-gnu -fsanitize-undefined-trap-on-error -fsanitize=undefined-trap %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
-// CHECK-UNDEFINED-TRAP: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute|function),?){19}"}}
-// CHECK-UNDEFINED-TRAP: "-fsanitize-trap=alignment,array-bounds,bool,enum,float-cast-overflow,float-divide-by-zero,function,integer-divide-by-zero,nonnull-attribute,null,object-size,pointer-overflow,return,returns-nonnull-attribute,shift-base,shift-exponent,signed-integer-overflow,unreachable,vla-bound"
-// CHECK-UNDEFINED-TRAP2: "-fsanitize-trap=alignment,array-bounds,bool,enum,float-cast-overflow,float-divide-by-zero,function,integer-divide-by-zero,nonnull-attribute,null,object-size,pointer-overflow,return,returns-nonnull-attribute,shift-base,shift-exponent,unreachable,vla-bound"
+// CHECK-UNDEFINED-TRAP: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute|function),?){18}"}}
+// CHECK-UNDEFINED-TRAP: "-fsanitize-trap=alignment,array-bounds,bool,enum,float-cast-overflow,float-divide-by-zero,function,integer-divide-by-zero,nonnull-attribute,null,pointer-overflow,return,returns-nonnull-attribute,shift-base,shift-exponent,signed-integer-overflow,unreachable,vla-bound"
+// CHECK-UNDEFINED-TRAP2: "-fsanitize-trap=alignment,array-bounds,bool,enum,float-cast-overflow,float-divide-by-zero,function,integer-divide-by-zero,nonnull-attribute,null,pointer-overflow,return,returns-nonnull-attribute,shift-base,shift-exponent,unreachable,vla-bound"
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED
-// CHECK-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|vptr|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){20}"}}
+// CHECK-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|vptr|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){19}"}}
 
 // RUN: %clang -target x86_64-apple-darwin10 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-DARWIN
-// CHECK-UNDEFINED-DARWIN: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){18}"}}
+// CHECK-UNDEFINED-DARWIN: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){17}"}}
 
 // RUN: %clang -target i386-unknown-openbsd -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-OPENBSD
-// CHECK-UNDEFINED-OPENBSD: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){18}"}}
+// CHECK-UNDEFINED-OPENBSD: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){17}"}}
 
 // RUN: %clang -target i386-pc-win32 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-WIN --check-prefix=CHECK-UNDEFINED-WIN32
 // RUN: %clang -target i386-pc-win32 -fsanitize=undefined -x c++ %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-WIN --check-prefix=CHECK-UNDEFINED-WIN32 --check-prefix=CHECK-UNDEFINED-WIN-CXX
 // RUN: %clang -target x86_64-pc-win32 -fsanitize=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-WIN --check-prefix=CHECK-UNDEFINED-WIN64
 // RUN: %clang -target x86_64-pc-win32 -fsanitize=undefined -x c++ %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-WIN --check-prefix=CHECK-UNDEFINED-WIN64 --check-prefix=CHECK-UNDEFINED-WIN-CXX
 // CHECK-UNDEFINED-WIN32: "--dependent-lib={{[^"]*}}ubsan_standalone-i386.lib"
 // CHECK-UNDEFINED-WIN64: "--dependent-lib={{[^"]*}}ubsan_standalone-x86_64.lib"
 // CHECK-UNDEFINED-WIN-CXX: "--dependent-lib={{[^"]*}}ubsan_standalone_cxx{{[^"]*}}.lib"
-// CHECK-UNDEFINED-WIN-SAME: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){18}"}}
+// CHECK-UNDEFINED-WIN-SAME: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){17}"}}
 
 // RUN: %clang -target i386-pc-win32 -fsanitize-coverage=bb %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COVERAGE-WIN32
 // CHECK-COVERAGE-WIN32: "--dependent-lib={{[^"]*}}ubsan_standalone-i386.lib"
 // RUN: %clang -target x86_64-pc-win32 -fsanitize-coverage=bb %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COVERAGE-WIN64
 // CHECK-COVERAGE-WIN64: "--dependent-lib={{[^"]*}}ubsan_standalone-x86_64.lib"
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=integer %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-INTEGER -implicit-check-not="-fsanitize-address-use-after-scope"
 // CHECK-INTEGER: "-fsanitize={{((signed-integer-overflow|unsigned-integer-overflow|integer-divide-by-zero|shift-base|shift-exponent),?){5}"}}
 
 // RUN: %clang -fsanitize=bounds -### -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix=CHECK-BOUNDS
 // CHECK-BOUNDS: "-fsanitize={{((array-bounds|local-bounds),?){2}"}}
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=all %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-FSANITIZE-ALL
 // CHECK-FSANITIZE-ALL: error: unsupported argument 'all' to option 'fsanitize='
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address,undefined -fno-sanitize=all -fsanitize=thread %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-FNO-SANITIZE-ALL
 // CHECK-FNO-SANITIZE-ALL: "-fsanitize=thread"
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=thread,undefined -fno-sanitize=thread -fno-sanitize=float-cast-overflow,vptr,bool,enum %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-PARTIAL-UNDEFINED
-// CHECK-PARTIAL-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|object-size|pointer-overflow|array-bounds|returns-nonnull-attribute|nonnull-attribute),?){16}"}}
+// CHECK-PARTIAL-UNDEFINED: "-fsanitize={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|unreachable|return|vla-bound|alignment|null|pointer-overflow|array-bounds|returns-nonnull-attribute|nonnull-attribute),?){15}"}}
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=shift -fno-sanitize=shift-base %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-FSANITIZE-SHIFT-PARTIAL
 // CHECK-FSANITIZE-SHIFT-PARTIAL: "-fsanitize=shift-exponent"
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fsanitize-trap=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-TRAP-UNDEF
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=vptr -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-TRAP-UNDEF
 // CHECK-VPTR-TRAP-UNDEF: error: invalid argument '-fsanitize=vptr' not allowed with '-fsanitize-trap=undefined'
 

 
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -### 2>&1 | FileCheck %s --check-prefix=CHECK-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fsanitize-recover -### 2>&1 | FileCheck %s --check-prefix=CHECK-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fsanitize-recover=all -### 2>&1 | FileCheck %s --check-prefix=CHECK-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fno-sanitize-recover -fsanitize-recover=undefined -### 2>&1 | FileCheck %s --check-prefix=CHECK-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fno-sanitize-recover=undefined -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fno-sanitize-recover=all -fsanitize-recover=thread -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-RECOVER-UBSAN
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fsanitize-recover=all -fno-sanitize-recover=undefined -### 2>&1 | FileCheck %s --check-prefix=CHECK-NO-RECOVER-UBSAN
-// CHECK-RECOVER-UBSAN: "-fsanitize-recover={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|vla-bound|alignment|null|vptr|object-size|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){18}"}}
+// CHECK-RECOVER-UBSAN: "-fsanitize-recover={{((signed-integer-overflow|integer-divide-by-zero|float-divide-by-zero|function|shift-base|shift-exponent|vla-bound|alignment|null|vptr|pointer-overflow|float-cast-overflow|array-bounds|enum|bool|returns-nonnull-attribute|nonnull-attribute),?){17}"}}
 // CHECK-NO-RECOVER-UBSAN-NOT: sanitize-recover
 
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fno-sanitize-recover=all -fsanitize-recover=object-size,shift-base -### 2>&1 | FileCheck %s --check-prefix=CHECK-PARTIAL-RECOVER
-// CHECK-PARTIAL-RECOVER: "-fsanitize-recover={{((object-size|shift-base),?){2}"}}
+// CHECK-PARTIAL-RECOVER: "-fsanitize-recover={{((shift-base),?){1}"}}
 
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=address -fsanitize-recover=all -### 2>&1 | FileCheck %s --check-prefix=CHECK-RECOVER-ASAN
 // CHECK-RECOVER-ASAN: "-fsanitize-recover=address"
 
 // RUN: %clang -target x86_64-linux-gnu %s -fsanitize=undefined -fsanitize-recover=foobar,object-size,unreachable -### 2>&1 | FileCheck %s --check-prefix=CHECK-DIAG-RECOVER
 // CHECK-DIAG-RECOVER: unsupported argument 'foobar' to option 'fsanitize-recover='
 // CHECK-DIAG-RECOVER: unsupported argument 'unreachable' to option 'fsanitize-recover='