stage2: implement function call inlining in the frontend

 * remove the -Ddump-zir thing. that's handled through --verbose-ir
 * rework Fn to have an is_inline flag without requiring any more memory
   on the heap per function.
 * implement a rough first version of dumping typed zir (tzir) which is
   a lot more helpful for debugging than what we had before. We don't
   have a way to parse it though.
 * keep track of whether the inline-ness of a function changes because
   if it does we have to go update callsites.
 * add compile error for inline and export used together.

inline function calls and comptime function calls are implemented the
same way. A block instruction is set up to capture the result, and then
a scope is set up that has a flag for is_comptime and some state if the
scope is being inlined.

when analyzing `ret` instructions, zig looks for inlining state in the
scope, and if found, treats `ret` as a `break` instruction instead, with
the target block being the one set up at the inline callsite.

Follow-up items:
 * Complete out the debug TZIR dumping code.
 * Don't redundantly generate ZIR for each inline/comptime function
   call. Instead we should add a new state enum tag to Fn.
 * comptime and inlining branch quotas.
 * Add more test cases.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/codegen.zig b/src/codegen.zig
index 6530b687e5..588c3dec4c 100644
--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -532,7 +532,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         self.code.items.len += 4;
 
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
 
                         const stack_end = self.max_end_stack;
                         if (stack_end > math.maxInt(i32))
@@ -576,7 +576,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         });
                     } else {
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
                         try self.dbgSetEpilogueBegin();
                     }
                 },
@@ -593,7 +593,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
 
                         try self.dbgSetPrologueEnd();
 
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
 
                         // Backpatch stack offset
                         const stack_end = self.max_end_stack;
@@ -638,13 +638,13 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         writeInt(u32, try self.code.addManyAsArray(4), Instruction.pop(.al, .{ .fp, .pc }).toU32());
                     } else {
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
                         try self.dbgSetEpilogueBegin();
                     }
                 },
                 else => {
                     try self.dbgSetPrologueEnd();
-                    try self.genBody(self.mod_fn.analysis.success);
+                    try self.genBody(self.mod_fn.data.body);
                     try self.dbgSetEpilogueBegin();
                 },
             }