+ The C code generated by GHC doesn't use higher-level features of C to be + able to control as precisely as possible what code is generated. + Moreover, it uses special features of gcc (such as, first class labels) + to produce more efficient code. +
+ STG C makes ample use of C's macro language to define idioms, which also
+ reduces the size of the generated C code (thus, reducing I/O times).
+ These macros are defined in the C headers located in GHC's includes
+ directory.
+
+
TailCalls.h
+ TailCalls.h
+ defines how tail calls are implemented - and in particular - optimised
+ in GHC generated code. The default case, for an architecture for which
+ GHC is not optimised, is to use the mini interpreter described in the STG paper.
+
+ For supported architectures, various tricks are used to generate
+ assembler implementing proper tail calls. On i386, gcc's first class
+ labels are used to directly jump to a function pointer. Furthermore,
+ markers of the form --- BEGIN --- and --- END
+ --- are added to the assembly right after the function prologue
+ and before the epilogue. These markers are used by the Evil Mangler.
+
+
+ +Last modified: Wed Aug 8 19:28:29 EST 2001 + + + +