CppCon 2024 Customizing Compilation Error Messages Formatting a Compile-Time String During Substitution Failure Patrick Roberts, P.E. Principal Software Engineer 1CppCon 2024 What problem does

CPPCON / 16TH SEPTEMBER 2020 CPPCON / 16TH SEPTEMBER 2020 JUST-IN-TIME COMPILATION: JUST-IN-TIME COMPILATION: THE NEXT BIG THING? THE NEXT BIG THING? BEN DEANE & KRIS JUSIAK - BEN DEANE & KRIS JUSIAK THE COMPILER... (/LIBRARY) IS THE COMPILER... JUST-IN-TIME (JIT) IS COMPILATION AT THE POINT OF NEED JUST-IN-TIME (JIT) IS COMPILATION AT THE POINT OF NEED 3 . 2WHAT IS JITTING? WHAT IS JITTING? INSTEAD THE COMPILER... (/LIBRARY) IS THE COMPILER... JUST-IN-TIME (JIT) IS COMPILATION AT THE POINT OF NEED JUST-IN-TIME (JIT) IS COMPILATION AT THE POINT OF NEED IT'S LIKE THE APPLICATION (/LIBRARY) IS THE COMPILER

build systems ■ xmake ■ bazel 2Outline 1. What are compilation databases? 2. How do modules change the status quo? 3. Build databases 3Compilation Databases: Overview ● JSON document ● Array of JSON file (optional) ○ Arguments (list of strings) or command (single string, shell escaped) 4Today: Compilation Databases ● Specified by the Clang project ○ https://clang.llvm.org/docs/JSONCompilationDatabase IDEs to understand how a source is used (e.g., highlighting the right side of an #if block) 5Compilation Databases: Example { "directory": "/path/to/build", "command": "/usr/lib64/ccache/c++ FLAG_SOUP

Just-in-Time Compilation A lecture on the last 60 years JF Bastien Software architect @jfbastien Presented at CppCon 2020. Just-in-Time compilers... we've all heard of them! What are they really on the screen than usual, from these papers. First, some definitions.JiT JiT Just-in-Time compilation With some artistic liberty, folks usually think of JIT as: The executable code changes after On modern systems: pages mapped X at some point in time are modified.AoT AoT Ahead-of-Time compilation Is AoT the opposite of JiT? C and C++ are pretty much AoT these days: compile code to a target

float a = get_half_of(23.0F);© 2021 Apex.AI, Inc. Wrong requests cause a compilation error image: Flaticon.com Compilation error float a = get_half_of(23); ██████ █████ █████████████{ ████ █████████ Test binary GoogleTest StaticTest Fixture ✅ image: Flaticon.com Compiler 1. Generate “compilation” tests image: Flaticon.com test_halving.cpp flags image: Flaticon.com test_compile_1.cpp image: Flaticon.com test_halving.cpp flags image: Flaticon.com Compiler 3. Interpret the compilation outcome image: Flaticon.com test_compile_1.cpp image: Flaticon.com test_compile_2.cpp© 2021

return T{}. func (); } 7 8 int main () { 9 // return H.func(); // OK 10 return D.func(); // compilation error 11 // return wrap< H >(); 12 // return wrap< D >(); 13 } � � (12): error: calling wrap(){ H.func(); } 7 8 int main () { 9 // return H.func(); // OK 10 // return D.func(); // compilation error 11 return wrap< H >(); 12 // return wrap< D >(); 13 } � � nvcc 12.612/66 Motivation 8 int main () { 9 // return H.func(); // OK 10 // return D.func(); // compilation error 11 return wrap< H >(); // compilation warning 12 // return wrap< D >(); 13 } � � (8): warning #20014-D:

"global" concepts • Clarify terminology that can be confusing • Shine some light on how C++ compilation works CppCon 2020 - The Structure of a Program 3Copyright © 2020 Bob Steagall K E W B C O M P accomplished by compilation and linking • Why? • Our human-readable text files must be converted to binary machine language CppCon 2020 - The Structure of a Program 18 Compilation Executable File C++ Executable • Compilation • The process of converting human-readable source code into binary object files • From a high-level perspective, there are four stages of compilation: • Lexical analysis

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1896 105.25 Ahead of Time Compilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1913 105.26 Static analyzer annotations and good performance, achieved using type inference and just-in-time (JIT) compilation (and optional ahead-of-time compilation), implemented using LLVM. It is multi-paradigm, combining features of imperative the actual argument types passed by the caller. For example, calling fib(1) will trigger the compilation of specialized version of fib optimized specifically for Int arguments, which is then re-used

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1896 105.25 Ahead of Time Compilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1913 105.26 Static analyzer annotations and good performance, achieved using type inference and just-in-time (JIT) compilation (and optional ahead-of-time compilation), implemented using LLVM. It is multi-paradigm, combining features of imperative the actual argument types passed by the caller. For example, calling fib(1) will trigger the compilation of specialized version of fib optimized specifically for Int arguments, which is then re-used

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1896 105.25 Ahead of Time Compilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1913 105.26 Static analyzer annotations and good performance, achieved using type inference and just-in-time (JIT) compilation (and optional ahead-of-time compilation), implemented using LLVM. It is multi-paradigm, combining features of imperative the actual argument types passed by the caller. For example, calling fib(1) will trigger the compilation of specialized version of fib optimized specifically for Int arguments, which is then re-used