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Disallow pointer arithmetic and C-arrays in a new mode called SAM ? #7

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mulle-nat opened this issue Nov 28, 2016 · 0 comments
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@mulle-nat
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Personally I don't need this, but it could be a kind of a marketing feature to compete with "safe" languages:

AAM could be expanded into SAM (safe AAM) to just allow "safe" Objective-C code and restrict "dangerous" C features.

The runtime can already check if class code is compiled with AAM or not and a Foundation may restrict loading such code if so desired. If the user assumes that "Foundation" code, written necessarily in regular ObjC mode is trustworthy, then any App code on top written in SAM would be able to guarantee being free of stack clobberings:

Brainstorm:

No C-arrays. No C pointers except id for passing stuff around. No calls to C functions.

char    foo[ 2];  // fails
id p;    // ok


*p // fails
p[ 1]  // fails
p = malloc( 20)   // fails
codeon-nat pushed a commit that referenced this issue Mar 28, 2020
…the branch where it's used

The existing code is not defined, you are not allowed
to produce non-null pointer from null pointer (F->FileSortedDecls here).
That being said, i'm not really confident this is fix-enough, but we'll see.

FAIL: Clang :: Modules/no-module-map.cpp (6879 of 16079)
******************** TEST 'Clang :: Modules/no-module-map.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -fmodules-ts -fmodule-name=ab -x c++-header /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map/a.h /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map/b.h -emit-header-module -o /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm
: 'RUN: at line 2';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -fmodules-ts -fmodule-file=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp -I/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map -verify
: 'RUN: at line 3';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -fmodules-ts -fmodule-file=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp -I/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map -verify -DA
: 'RUN: at line 4';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -fmodules-ts -fmodule-file=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp -I/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map -verify -DB
: 'RUN: at line 5';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -fmodules-ts -fmodule-file=/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp -I/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/Inputs/no-module-map -verify -DA -DB
: 'RUN: at line 7';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -E /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm -o - | /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/FileCheck /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp
: 'RUN: at line 8';   /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/lib/clang/10.0.0/include -nostdsysteminc -frewrite-imports -E /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/tools/clang/test/Modules/Output/no-module-map.cpp.tmp.pcm -o - | /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/FileCheck /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/test/Modules/no-module-map.cpp
--
Exit Code: 2

Command Output (stderr):
--
/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Serialization/ASTReader.cpp:1526:50: runtime error: applying non-zero offset 8 to null pointer
    #0 0x3a9bd0c in clang::ASTReader::ReadSLocEntry(int) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Serialization/ASTReader.cpp:1526:50
    #1 0x328b6f8 in clang::SourceManager::loadSLocEntry(unsigned int, bool*) const /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Basic/SourceManager.cpp:461:28
    #2 0x328b351 in clang::SourceManager::initializeForReplay(clang::SourceManager const&) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Basic/SourceManager.cpp:399:11
    #3 0x3996c71 in clang::FrontendAction::BeginSourceFile(clang::CompilerInstance&, clang::FrontendInputFile const&) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Frontend/FrontendAction.cpp:581:27
    #4 0x394f341 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:956:13
    #5 0x3a8a92b in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:290:25
    #6 0xaf8d62 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/tools/driver/cc1_main.cpp:250:15
    #7 0xaf1602 in ExecuteCC1Tool /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/tools/driver/driver.cpp:309:12
    #8 0xaf1602 in main /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/tools/driver/driver.cpp:382:12
    #9 0x7f2c1eecc2e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
    #10 0xad57f9 in _start (/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/bin/clang-10+0xad57f9)

SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/clang/lib/Serialization/ASTReader.cpp:1526:50 in

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374328 91177308-0d34-0410-b5e6-96231b3b80d8
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